Information
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Patent Grant
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6757220
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Patent Number
6,757,220
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Date Filed
Friday, July 28, 200023 years ago
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Date Issued
Tuesday, June 29, 200420 years ago
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Inventors
-
Original Assignees
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Examiners
- Miska; Vit
- Goodwin; Jeanne-Marguerite
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CPC
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US Classifications
Field of Search
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International Classifications
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Abstract
An electronically controlled timepiece includes an analog circuit (160) driven by a power source (22), a logic circuit (170) driven by a constant voltage regulator circuit (161) forming part of the analog circuit, an oscillator circuit (51) driven by the constant voltage regulator, a power source switch (162) for cutting off the supply of power to the analog circuit other than the constant voltage regulator circuit from the power source during a time correction operation, and a clock cutoff gate (171) for cutting off a clock input from the oscillator circuit to the logic circuit. During the time correction operation, power consumption is reduced because only the oscillator circuit and the constant voltage regulator circuit are operative. The oscillator circuit is not suspended, and an error in time display is eliminated.
Description
TECHNICAL FIELD
The present invention relates to an electronically controlled timepiece that controls timepiece hand driving in response to a signal, as a reference, from an oscillator circuit that employs a time standard source such as a crystal oscillator, a power supply control method for the electronically controlled timepiece and a time correction method for the electronically controlled timepiece.
BACKGROUND ART
In one of known electronically controlled mechanical timepieces that are controlled by making use of an IC or a crystal oscillator, a generator converts, into electrical energy, mechanical energy released by a mainspring, the electrical energy drives a rotation controller, which controls a current flowing through a coil of the generator, and hands secured to train wheels that transmit the mechanical energy from the mainspring to the generator are accurately driven to indicate accurate time.
Electrical energy from the generator is once stored in a smoothing capacitor, and the power from the capacitor drives the rotation controller. Since the capacitor is supplied with an alternating-current electromotive force in synchronization with the rotation period of the generator, it is not necessary to store power for a long period of time to enable the rotation controller having an IC or a crystal oscillator to operate. Conventionally, a relatively small capacitance capacitor enabling the IC or the crystal oscillator to operate for several seconds, i.e., a capacitor of 10 μF or so is employed.
The electronically controlled mechanical timepiece needs no motor because the mainspring is a power source for driving timepiece hands, and is low cost with a small component count. It is sufficient if a small amount of electrical energy needed to drive an electrical circuit is generated. A small input energy is enough to drive the timepiece.
The electronically controlled mechanical timepiece has the following drawback. When a time correction operation (a timepiece hand setting operation) is performed with the crown pulled out, each of an hour hand, a minute hand, and a second hand is stopped to set an accurate time. The stop of the hands stops train wheels, and thus the generator as well.
The input of the electromotive force to the smoothing capacitor from the generator is suspended, while the IC is continuously driven. The charge stored in the capacitor is discharged to the IC side, and a voltage across terminals of the IC gradually drops. The voltage applied to the IC thus drops below an oscillation stop voltage (Vstop, for instance, 0.6 V), leading to the stop of the rotation controller.
When the oscillation of the IC stops, the power consumption is reduced, and the voltage drop rate in the capacitor also becomes slow. When the time correction operation takes time long enough to cause the voltage of the capacitor to drop below the oscillation stop voltage, the capacitor typically falls to a voltage of 0.3 to 0.4 V slightly lower than the oscillation stop voltage. When the time correction operation (hand setting time) becomes excessively long, to several minutes, for instance, the capacitor is fully discharged with the voltage thereof dropped to zero V.
Even if the generator starts rotating with the crown pushed into after the hand setting, the capacitor, the voltage of which has once dropped below the oscillation stop voltage as a result of discharge, takes time before the capacitor is charged again to be high enough to reach a drive start voltage (voltage capable of driving the IC) for the rotation controller. The IC (an oscillator circuit) remains inoperative throughout, and no accurate time control is performed.
Specifically, when the crown is pulled out to a second step (for a hand setting mode) from a zero step (for a normal hand driving mode) or from a first step (for a calendar correction mode) at time point A as shown in
FIG. 26
, the rotor of the generator stops, stopping charging a capacitor C
1
. On the other hand, the capacitor C
1
continuously feeds electrical energy to the rotation controller (including a “drive IC” in a drive circuit for driving the crystal oscillator as a time standard source), thereby allowing the crystal oscillator to continuously oscillate.
The voltage of the power source capacitor C
1
gradually drops. At time point B
1
(within three minutes from time A, for instance), the hand setting operation ends, and the crown is pushed in, moving from the second step to the first step or zero step (for the normal operation). The generator becomes operative again, restarting the charging of the power source capacitor C
1
, and raising the voltage of the power source capacitor C
1
. In this case, the oscillation of the crystal oscillator continuously oscillates, the drive circuit (the rotation controller) quickly resumes rotation control of the rotor (brake control), and an indication error subsequent to the hand setting becomes zero.
When the hand setting operation is prolonged to be longer than three minutes, for instance, the voltage of the capacitor C
1
drops below the oscillation stop voltage (Vstop, 0.6 V, for instance) of the drive circuit, and the oscillation stops at time B
2
at the moment the hand setting operation ends. Even if the crown is moved to the first step at point B
2
, the rotation controller takes the sum of time T
1
and time T
2
before it resumes rotation control of the rotor, leading to an indication error.
The time T
1
is a duration of time, during which the power source capacitor C
1
is charged to a voltage (Vstart) on which the drive circuit and the oscillator circuit in the rotation controller normally operate. The voltage Vstart is typically higher than the voltage Vstop, and is 0.7 V, for instance.
The time T
2
is a duration of time from the application of the oscillation start voltage (Vstart) until the oscillator circuit starts oscillating. The time T
2
becomes longer as the voltage of the power source capacitor C
1
is lower, and ranges from several seconds to several minutes, as shown in FIG.
27
. For instance, when the oscillation start voltage (Vstart=0.7 V) is reached with the power source capacitor C
1
gradually charged, the time T
2
is approximately
20
seconds with the voltage (0.7 V) applied thereto.
When the hand setting operation takes time, the voltage of the power source capacitor C
1
drops, thereby stopping the oscillation. Subsequent to the end of the hand setting operation, the oscillator circuit takes time T
1
+T
2
before the start of the oscillation. Because of a lower voltage applied thereto, the oscillator circuit takes several seconds to several minutes for T
2
alone. Before the start of the oscillation, the rotation of the rotor is not controlled. The hands gain or lose time, suffering from a substantial indication error.
The use of a large capacitance capacitor C
1
to permit a longer hand setting time is contemplated. The oscillator circuit is thus prevented from stopping even if the hand setting takes three minutes or longer.
The use of a large capacitance capacitor slows the rise rate of the power source voltage. When the mainspring is released and stopped, it takes a long time to increase the voltage across the capacitor from the state in which no charge is stored in the power source capacitor. For a long time from the start of tightening of the mainspring to the rise of the power source voltage, the hands remain unable to present accurate time. In this case, there is a possibility that the user may mistake the state for a timepiece failure. Increasing the capacitance of the capacitor is thus not practical.
Increasing the power generation capacity of the generator to complete charging in a short time is contemplated. This arrangement increases the size of the generator, and also needs to increase the size of the mainspring as the torque to be transferred from the mainspring for feeding mechanical energy to the generator increases. This arrangement cannot be adopted for use in wristwatches, which are subject to the limitation of area and thickness dimensions.
In some of a variety of electronically controlled timepieces, such as a self-winding generator timepiece, a solar-cell charging timepiece, a battery driven timepiece, other than the electronically controlled mechanical timepiece, an oscillator circuit or an IC is stopped during a time correction operation to reduce power consumption and to prolong operation time. In this case, it takes several seconds to several minutes for the oscillator circuit to stably operate. A time error is also introduced.
It is an object of the present invention to provide an electronically controlled timepiece, a power supply control method for the electronically controlled timepiece, and a time correction method for the electronically controlled timepiece.
DISCLOSURE OF THE INVENTION
An electronically controlled timepiece of the present invention which includes a power source, an analog circuit driven by the power source, a power supply circuit for a logic circuit arranged in the analog circuit, the logic circuit driven by the output of the power supply circuit therefor, and an oscillator circuit driven by the output of the power supply circuit for the logic circuit. The electronically controlled timepiece further includes a power source switch for suspending the supply of electrical energy to the analog circuit other than the power supply circuit for the logic circuit from the power source during a time correction operation of the electronically controlled timepiece, and clock input limiting means for suspending a clock input from the oscillator circuit to the logic circuit during the time correction operation.
In accordance with the present invention, the power source switch suspends the supply of electrical energy from the power source, such as a capacitor or a battery, to the analog circuit other than the power supply circuit for the logic circuit during the time correction operation (hand setting operation), and the clock limiting means suspends the clock input from the oscillator circuit to the logic circuit. During the hand setting operation, only both the oscillator circuit and the power supply circuit for the logic circuit required to drive the oscillator circuit are driven with the remaining circuits all inoperative. With this arrangement, power consumption during the hand setting operation is reduced. When the capacitance of the capacitor is small, the voltage drop in the power source capacitor is limited during a typical hand setting operation (for instance, 3 to 5 minutes), and the driving of the oscillator circuit is continuously performed. With the oscillator circuit continuously operating during the hand setting operation, a normal control operation is quickly resumed after the hand setting operation, and the indication error at the shifting back from the hand setting operation is eliminated. With the power consumption reduced, there is no need for a large-sized generator, and the present invention is implemented in a wristwatch, which is typically subject to the limitation of area and thickness dimensions.
The power supply circuit for the logic circuit employs a constant voltage regulator.
The electronically controlled timepiece preferably includes logic circuit initializing means for initializing the internal status of the logic circuit during the time correction operation (hand setting operation).
If control information prior to the hand setting operation remains in the logic circuit, governing control of a rotor is not smoothly performed at the shifting back from the hand setting operation, and the time taken before the start of the governing control may be included as an error. In contrast, if the internal status of the logic circuit is initialized when the clock input to the logic circuit is cut off at the hand setting operation, the governing control of the rotor at the shifting back from the hand setting operation is smoothly performed, and the time indication error is reliably eliminated.
An electronically controlled timepiece preferably includes an external control member for setting two-step statuses of a normal mode and a time correction mode, and an external control member detector circuit for detecting the status of the external control member, wherein the external control member detector circuit includes first and second inverters, a first signal line for connecting the output of the first inverter to the input of the second inverter, a second signal line for connecting the output of the second inverter to the input of the first inverter, and a selection switch for connecting a signal input line to one of the first and second signal lines with the external control member in the time correction mode, and for connecting the signal input line to the other of the first and second signal lines with the external control member in the other mode.
A crown detector circuit
100
shown in
FIG. 28
has typically been used to detect the pulled status of the external control member such as a crown or a button. For instance, the pulled statuses of the crown of the electronically controlled mechanical timepiece include a normal zero step (in which the mainspring is tightened by turning the crown with the hands turning and the generator generating), a first step (in which a calendar is corrected by turning the crown with the hands turning and the generator generating), and a second step (in which time correction is performed by turning the crown with the rotor stopping moving, the hands motionless, and the generator not generating).
The crown detector circuit
100
includes a switch
101
which is turned on and off depending on the pulled status of the crown, two pull-down resistors
102
and
103
, and an inverter
104
. The gate of the pull-down resistor
102
is at a voltage VDD (high level), and the pull-down resistor
102
is normally turned on. The gate of the pull-down resistor
103
is connected to the pull-down resistor
102
through the inverter
104
. The switch
101
is turned off (open) with the crown in the zero step or the first step, and is turned on with the crown in the second step (closed). When the switch
101
is turned off with the crown in the zero step or the first step, the pull-down resistor
102
is turned on, a voltage VSS, namely, a low-level signal is input to the inverter
104
, and the output signal of the inverter
104
is transitioned to a high-level signal. The pull-down resistor
103
receives, at the gate thereof, the high-level signal, thereby turning itself on.
When the switch
101
is turned on with the crown in the second step, the voltage VDD, namely, a high-level signal is input to the inverter
104
, and the output of the inverter
104
is transitioned to a low-level signal. As described above, depending on the pulled status of the crown, the crown detector circuit
100
alternates between a “high-level”, signal and a “low-level” signal.in the output thereof, thereby detecting the position of the crown.
In the conventional crown detector circuit
100
, the pull-down resistor
102
is turned on with the crown in the second step, and the pull-down resistor
102
consumes energy. Instead of the crown, a dedicated button is occasionally employed to set the hands. When the hands are set using the external control member, such as the crown or the button, an external control member detector circuit for detecting the status of the external control member has the same construction as that of the crown detector circuit
100
, and thus suffers from the same problem.
In contrast, the electronically controlled timepiece having the above-described external control member detector circuit employing the logic circuit almost eliminates energy consumption by the external control member, and therefore substantially reduces power consumption during the hand setting operation.
An electronically controlled timepiece of the present invention preferably includes a mechanical energy source, a generator which is driven by the mechanical energy source, and generates an electromotive force, thereby supplying electrical energy, and a rotation controller, driven by the electrical energy, for controlling the rotation period of the generator.
In the electronically controlled timepiece, the capacitance of the capacitor as the power source is small. The power consumption for the hand setting operation is reduced with the present invention implemented, the time required for the hand setting operation is assured, and the ease of use is attained.
A power supply control method for an electronically controlled timepiece of the present invention, which includes a power source, an analog circuit driven by the power source, a power supply circuit for a logic circuit arranged in the analog circuit, the logic circuit driven by the output of the power supply circuit therefor, and an oscillator circuit driven by the output of the power supply circuit for the logic circuit, includes the step of suspending the supply of electrical energy to the analog circuit other than the power supply circuit for the logic circuit from the power source during a time correction operation of the electronically controlled timepiece, and the step of suspending a clock input from the oscillator circuit to the logic circuit during the time correction operation.
In accordance with the present invention, during the time correction operation of the electronically controlled timepiece, the supply of electrical energy to the analog circuit other than the power supply circuit for the logic circuit from the power source such as a capacitor or a battery is suspended, and the clock input from the oscillator circuit to the logic circuit is suspended. The power consumption during the hand setting operation is reduced. Even with a small capacitance capacitor, the voltage drop in the power source capacitor is limited during a typical hand setting operation (for instance, 3 to 5 minutes), and the driving of the oscillator circuit is continuously performed. At the shifting back from the hand setting operation, a normal control operation is quickly resumed after the hand setting operation, and the time indication error at the shifting back from the hand setting operation is eliminated.
During the hand setting operation of the electronically controlled timepiece, the internal status of the logic circuit is preferably initialized. If the internal status of the logic circuit is initialized when the clock input to the logic circuit is cut off at the hand setting operation, the governing control of the rotor at the shifting back from the hand setting operation is smoothly performed, and the time indication error is reliably eliminated.
An electronically controlled timepiece of the present invention, which includes a mechanical energy source, a generator, driven by the mechanical energy source, for outputting electrical energy, a storage unit for storing electrical energy output by the generator, and a rotation controller, driven by electrical energy supplied by the storage unit, for controlling the rotation period of the generator, includes a power supply control unit for suspending the supply of electrical energy from the storage unit to the rotation controller while the generator stops the operation thereof in response to the time correction operation, and an indication error corrector unit for correcting an error in time indication until the rotation controller resumes a normal operation, when the power supply control unit restarts the supply of electrical energy from the storage unit to the rotation controller in response to the operation of the generator.
In accordance with the present invention, the power supply control unit suspends the supply of electrical energy from the storage unit to the rotation controller when the generator stops the operation thereof during the time correction operation (hand setting operation). Although the oscillator circuit of the rotation controller stops operating, the storage unit is maintained in a charged state during the suspension of the operation of the generator.
Even before the generator fully reaches the operation thereof at the shifting back from the hand setting operation, the storage unit feeds electrical energy to the rotation controller to cause the rotation controller to be fully operative. A time lag prior to the operation of the rotation controller is eliminated, and an error in the time control at the hand setting operation is thus minimized. Since the voltage of the storage unit is maintained at a relatively high level, the time prior to the start of the oscillator circuit of the rotation controller is shortened, and the rotation controller is quickly set to be operative.
With the indication error corrector unit incorporated, the indication error of the hand before the normal operation of the rotation controller is corrected to the extent that the indication error is eliminated or minimized.
The indication error corrector unit may be designed to perform a constant quantity correction corresponding to a predetermined value, or may set a correction value in accordance with a voltage of the storage unit.
The indication error corrector unit may adjust a correction value by detecting temperature.
Specifically, the indication error corrector unit may include a temperature sensor, a voltage detector for measuring a voltage of the storage unit, and a correction value setter for setting a correction value based on values detected by the temperature sensor and the voltage detector.
Since the voltage of the storage unit is maintained at a certain magnitude, the time, which the oscillator circuit, with a certain voltage applied thereto, takes to start oscillation, is substantially constant. By performing a constant quantity correction corresponding to a certain value, the indication error is sufficiently reduced. When a correction value is adjusted by detecting the actual voltage of the storage unit, a highly precise correction is performed to minimize the indication error.
The time prior to the start of the oscillation with the voltage applied to the oscillator circuit varies with temperature as shown in FIG.
16
. For this reason, the temperature sensor included in the electronically controlled timepiece measures temperature in the vicinity of the oscillator circuit, and the correction value is adjusted in accordance with the measured temperature. A more precise correction is thus performed. The indication error, under high temperature conditions or low temperature conditions, is thus further minimized.
The power supply control unit preferably includes a switch which is connected in series with the storage unit and is closed while the generator is running, and is opened while the generator is not running.
An electrical switch is acceptable as the switch, but a mechanically driven switch is preferable. When the electrical switch is used, the supply of power may be occasionally not completely blocked. In such a case, as well, a mere leakage current (1 nA) of a silicon diode constituting the electrical switch is discharged. The switch cutoff effect of the switch is almost identical to that of the mechanically driven switch. The use of the mechanically driven switch is preferable from the standpoint of the fully cutting off the supply of power.
The switch is preferably a mechanically driven switch that is opened when a crown remains pulled out to a time correction (hand setting) mode, and is closed when the crown is pushed into to a normal mode. With the switch opened and closed in response to the operation of the crown, the switch is interlocked with the hand setting operation.
A second storage unit (a second capacitor) is preferably connected in parallel with the storage unit. With the second storage unit arranged, power is continuously fed by the second storage even if the timepiece suffers from a mechanical shock, with the switch chattering. This arrangement prevents the rotation controller from being shut down by the chattering.
A time correction method for an electronically controlled timepiece, which includes a mechanical energy source, a generator, driven by the mechanical energy source, for outputting electrical energy, a storage unit for storing electrical energy output by the generator, and a rotation controller, driven by electrical energy supplied by the storage unit, for controlling the rotation period of the generator, includes the step of suspending the supply of electrical energy from the storage unit to the rotation controller during a time correction operation of the electronically controlled timepiece, and the step of correcting an error in time indication until the rotation controller resumes a normal operation when the supply of electrical energy from the storage unit to the rotation controller is restarted at the end of the time correction operation.
At the end of the time correction operation, the indication error may be corrected by a constant quantity correction corresponding to a predetermined value or may be corrected by a correction value set in response to the voltage of the storage unit. At the end of the time correction operation, temperature may be detected, and the correction value may be adjusted in accordance with the detected temperature.
In accordance with the present invention, the power supply control unit suspends the supply of electrical energy from the storage unit to the rotation controller when the generator stops the operation thereof during the time correction operation. The storage unit is maintained in a charged state during the suspension of the operation of the generator. Immediately subsequent to the shifting back from the time correction operation, the storage unit feeds electrical energy to the rotation controller to cause the rotation controller to be operative. Since the applied voltage is maintained at a relatively high level, the rotation controller is quickly set to be operative, and the indication error subsequent, to the time correction operation is reduced.
Furthermore, since the indication error is corrected in accordance with the voltage value of the storage unit and temperature, the indication error of the hands prior to the normal operation of the rotation controller is corrected. The indication error is thus eliminated.
An electronically controlled timepiece of the present invention, which includes a mechanical energy source, a generator, driven by the mechanical energy source, for outputting electrical energy, and a rotation controller, driven by electrical energy, for controlling the rotation period of the generator, includes a main storage unit for storing electrical energy supplied by the generator to drive the rotation controller, an auxiliary storage unit connected in parallel with the main storage unit through a mechanically driven switch that is interlocked with a time correction operation, and a charge control circuit, arranged between the main storage unit and the auxiliary storage unit, for adjusting charging currents to the main storage unit and the auxiliary storage unit, and a direction and a magnitude of a current flowing between the main storage unit and the auxiliary storage unit.
The charge control circuit preferably makes the charging current (charge quantity) to the auxiliary storage unit smaller than the charging current (charge quantity) to the main storage unit when the mechanically driven switch is closed to charge the main storage unit and the auxiliary storage unit with electrical energy from the generator, and allows the auxiliary storage unit to charge the main storage unit when the voltage of the auxiliary storage unit is higher than the voltage of the main storage unit.
Since the present invention includes the auxiliary storage unit that is disconnected from the main storage unit and the generator by the mechanically driven switch, the auxiliary storage unit is maintained in a charged state even when the generator stops the operation thereof during the time correction operation (hand setting operation) in the middle of the normal hand driving. Even if the terminal voltage across the main storage unit drops below the voltage capable of driving the rotation controller at the shifting back from the hand setting operation, a current flows from the auxiliary storage unit to the main storage unit with the mechanically controlled switch closed. With its voltage increased, the main storage unit drives the rotation controller, and a time lag prior to the operation of the rotation controller is eliminated, and an error in the time control at the hand setting operation (an error in the time indication subsequent to the time correction operation) is thus minimized.
When the hand setting operation takes time, when the timepiece has been left unattended for a long period of time to the degree that the terminal voltage across the auxiliary storage unit drops as a result of a self-discharge, the mechanically driven switch is closed to allow a current to flow from the generator to each storage unit. In this case, the charge control circuit for adjusting the direction and the magnitude of the current makes the charging current to the main storage unit larger than the charging current to the auxiliary storage unit, and the main storage unit is charged to be high enough to quickly drive the rotation control circuit. Even after the timepiece has been left unattended for a long period of time, the rotation controller is quickly driven. An error due to a time lag prior to the start of the driving of the rotation controller is reduced, and an error in the time control during the hand setting operation is minimized.
The present invention thus assures both the startup capability subsequent to the hand setting and the accuracy of the hand setting at the same time.
Preferably, the charge control circuit composed of a passive element only is used to control the charging and discharging between the main storage unit and the auxiliary storage unit. The use of the charge control circuit composed of the passive element reduces power consumption and the generation capacity of the generator, compared to the arrangement in which a comparator, i.e., an active element, is used.
When the charging and discharging are controlled between the two storage units (such as capacitors), i.e., the main storage unit and the auxiliary storage unit, the control of the charging and discharging of the capacitor is typically performed by detecting the voltage of each capacitor using a comparator, and by using the output of the comparator to cause a switch circuit, composed of transistors, to operate. In such a timepiece, the comparator is an active element, and the comparator needs power to detect the voltage. The power consumption thus increases.
In a system, such as this timepiece, in which the generation capacity is extremely small, the generation capacity of the generator needs to be increased from a current level to supply power to the comparator. To increase the generation capacity of the generator, means for increasing torque or increasing the size of the generator itself may be contemplated.
In the former means, increasing the energy supply from the mainspring allows the mainspring to fast release. The duration of time of the releasing of the mainspring from the fully tightened position thereof is shortened. In the latter means, the size of the generator becomes large, presenting difficulty in the layout of components in a timepiece that has a limited space available. As a result, the size of the timepiece itself is increased.
Since the present invention includes the charge control circuit having the passive element, the power consumption thereof is small, compared to the arrangement in which the comparator, as an active element, is employed. A generator having a small generation capacity thus works.
The capacitance of the main storage unit is preferably set to be equal to or lower than the capacitance of the auxiliary storage unit. With this arrangement, the voltage of the main storage unit is rapidly increased by allowing the current to f low from the auxiliary storage unit when the main storage unit is discharged. The drive circuit, driven by the main storage unit, is also rapidly driven.
Preferably, the mechanically driven switch is opened during the time correction operation, and is closed at the end of the time correction.
With this arrangement, the auxiliary storage unit is reliably cut off from the rotation controller with the generator stopped during the time correction operation (hand setting operation), and the auxiliary storage unit keeps the charged state thereof for a long period of time, and a long hand setting time is thus permitted.
The charge control circuit preferably includes a resistor and a diode connected in parallel with the resistor, wherein the diode is configured with the reverse direction thereof aligned with the direction of a current charging the auxiliary storage unit from the generator and the forward direction thereof aligned with the direction of a current of the auxiliary storage unit charging the main storage unit.
When the generator charges each storage unit in this arrangement, a current flows through the auxiliary storage unit via the resistor connected in parallel with the diode. The charge quantity to the main storage unit and to the auxiliary storage unit is controlled by the resistance of the resistor. For instance, the use of a resistor having a high resistance as large as 100 MΩ allows less current to flow to the auxiliary storage unit and more current to flow to the main storage unit, thereby rapidly charging the main storage unit. By setting an appropriate resistance to the resistor, the charge quantity to the main storage unit is controlled.
At the time of the shifting back from the hand setting operation, the charging of the main storage unit by the auxiliary storage unit is performed through the diode with a small charging loss involved therein, compared to the charging performed through the resistor.
The charge control circuit may include a diode only having a reverse leakage current, and wherein the diode is configured with the reverse direction thereof aligned with the direction of a current charging the auxiliary storage unit from the generator and the forward direction thereof aligned with the direction of a current of the auxiliary storage unit charging the main storage unit.
With this arrangement, a small reverse leakage current of the diode is fed to the auxiliary storage unit when each storage unit is charged with the generator. For this reason, less current flows to the auxiliary storage unit, while more,current flows to the main storage unit.
At the time of shifting back from the hand setting operation, the charging current from the auxiliary storage unit to the main storage unit is aligned with the forward direction of the diode, and the voltage drop and charging loss therethrough are thus reduced.
Furthermore, if the charging control circuit is constructed of a diode only, the component count of the charging control circuit, and thus of the timepiece, becomes smaller, leading reduced manufacturing costs.
The charge control circuit may include a resistor and a one-way element connected in parallel with the resistor, wherein the one-way element is configured to cut off a current flowing in a direction to charge the auxiliary storage unit from the generator and to conduct a current of the auxiliary storage unit flowing in a direction to charge the main storage unit. In this case, the one-way element may be a diode having no reverse leakage current.
As in the charge control circuit constructed of the diode and the resistor in parallel connection, the generator charges each of the storage units, and the auxiliary storage unit is charged through the resistor so that the charge quantity to the main storage unit is large for rapid charging. When the auxiliary storage unit charges the main storage unit, the charging is performed through the one-way element, and a charging loss to the main storage unit is minimized.
When the one-way element, such as a diode having no reverse leakage current, allowing currents flowing therethrough in one direction only, is used, an error in the charge quantity due to the reverse leakage current is not created. The charging current is thus precisely controlled.
An electronically controlled timepiece preferably includes an indication error corrector unit for correcting an error in time indication until the rotation controller resumes a normal operation when the supply of electrical energy of the main storage unit to the rotation controller is restarted with the mechanically driven switch closed.
With the indication error corrector unit incorporated, the time indication error until the rotation controller resumes the normal operation is corrected, and the indication error is eliminated or minimized.
In this case, again, the indication error corrector unit may be designed to perform a constant quantity correction corresponding to a predetermined value, or may set a correction value in accordance with a voltage of the storage unit. Furthermore, the indication error corrector unit may adjust a correction value by detecting temperature. More specifically, the indication error corrector unit may includes a temperature sensor, a voltage detector for measuring a voltage of the storage unit, a correction value setter for setting a correction value based on values detected by the temperature sensor and the voltage detector.
A power supply control method for an electronically controlled timepiece of the present invention which includes a mechanical energy source, a generator, driven by the mechanical energy source, for outputting electrical energy, and a rotation controller, driven by electrical energy, for controlling the rotation period of the generator, includes the step of arranging a main storage unit which stores electrical energy supplied by the generator to drive the rotation controller and connecting an auxiliary storage unit in parallel with the main storage unit through a mechanically driven switch, the step of opening the mechanically controlled switch during a time correction operation of the electronically controlled timepiece, and the step of flowing a current from the auxiliary storage unit to the main storage unit to charge the main storage when the voltage of the auxiliary storage unit is higher than the voltage of the main storage unit with the mechanically driven switch closed at the end of a time correction operation, and the step of making a charging current supplied from the generator to the main storage unit greater than a charging current supplied from the generator to the auxiliary storage unit when the voltage of the auxiliary storage unit is not higher than the voltage of the main storage unit.
In this arrangement as well, the main storage unit is charged to be high enough to quickly drive the rotation control circuit at the shifting back from the hand setting operation and an error due to a time lag before the start of the driving of the rotation controller is reduced, and an error in the time control during the hand setting operation (an error in the time indication subsequent to the time correction operation) is minimized.
Even after the timepiece has been left unattended for a long period of time, the rotation controller is quickly driven. An error due to a time lag before the start of the driving of the rotation controller is reduced, and an error in the time control during the hand setting operation is minimized. The present invention thus assures both the startup capability subsequent to the hand setting and the accuracy of the hand setting at the same time.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a block diagram showing the construction of an electronically controlled timepiece of a first embodiment of the present invention.
FIG. 2
is a circuit diagram showing the construction of a control circuit of the first embodiment.
FIG. 3
is a circuit diagram of a rotation controller of the first embodiment.
FIG. 4
is a timing chart of the circuit of the first embodiment.
FIG. 5
is a timing chart of the circuit of the first embodiment.
FIG. 6
is a waveform diagram showing an alternating-current output signal of a generator in the circuit of the first embodiment.
FIG. 7
is a flow chart showing a control method of the first embodiment.
FIG. 8
is a flow chart showing a power supply control method of the first embodiment.
FIG. 9
is a flow chart showing a crown position detection process in the power supply control method of the first embodiment.
FIG. 10
is a block diagram showing the construction of an electronically controlled timepiece of a second embodiment of the present invention.
FIG. 11
is a circuit diagram showing the construction of a control circuit of the second embodiment.
FIG. 12
is a block diagram showing a power supply control unit of the second embodiment.
FIG. 13
is a block diagram showing an indication error corrector unit of the second embodiment.
FIG. 14
shows an initial value setting table in the indication error corrector unit.
FIG. 15
is a diagram showing variations in the voltage of a capacitor and the voltage applied to a drive circuit in the second embodiment.
FIG. 16
is a graph showing applied voltage versus oscillation start time characteristics of an oscillator circuit with temperature as a parameter.
FIG. 17
is a table listing inputs and outputs of an AID converter in the indication error corrector unit.
FIG. 18
is a block diagram showing the construction of an electronically controlled timepiece of a third embodiment of the present invention.
FIG. 19
is a circuit diagram showing the construction of a power supply circuit of the third embodiment of the present invention.
FIG. 20
is a diagram showing variations in the voltage of a capacitor and the voltage applied to a drive circuit in the third embodiment.
FIG. 21
is a diagram showing variations in the voltage of a capacitor and the voltage applied to a drive circuit in the third embodiment.
FIG. 22
is a circuit diagram showing the construction of a power supply circuit of a fourth embodiment of the present invention.
FIG. 23
is a block diagram showing the construction of an electronically controlled timepiece of a fifth embodiment of the present invention.
FIG. 24
is a circuit diagram showing the construction of a power supply circuit of the fifth embodiment.
FIG. 25
is a circuit diagram showing an modification of the second embodiment.
FIG. 26
is a diagram showing variations in the voltage of a capacitor and the voltage applied to a drive circuit a conventional art.
FIG. 27
is a graph showing applied voltage versus oscillation start time characteristics of an oscillator circuit.
FIG. 28
is a circuit diagram showing a conventional crown detector circuit.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to the drawings, the embodiments of the present invention are now discussed.
FIG. 1
is a block diagram showing the construction of an electronically controlled mechanical timepiece that is an electronically controlled timepiece of a first embodiment of the present invention.
The electronically controlled mechanical timepiece includes a mainspring
1
a
as a mechanical energy source, accelerating train wheels
7
as mechanical energy transmission means for transmitting torque of the mainspring la to a generator
20
, and a hand
13
, as a time display unit for indicating time, connected to the accelerating train wheels
7
.
The generator
20
is driven by the mainspring
1
a
via the accelerating train wheels
7
, and generates an electromotive force to supply electrical energy. The alternating-current output from the generator
20
is rectified by a rectifier circuit
21
, which has at least one of the functions of stepup and rectification, full-wave rectification, half-wave rectification, and transistor rectification, and is stepped up as required. The alternating-current voltage is then fed to a power supply circuit
22
as a power source such as a capacitor to charge it.
Referring to
FIG. 2
, a brake circuit
120
is added to the generator
20
in this embodiment. Specifically, the brake circuit
120
includes a switch
121
which applies a brake by making a closed loop by shorting a first alternating-current output terminal MG
1
to which the alternating-current signal (alternating current) generated by the generator
20
is output, and a second alternating-current output terminal MG
2
. The brake circuit
120
is assembled into the generator
20
which also works as a governor as shown in FIG.
1
. The switch
121
includes an analog switch or a semiconductor switch (bilateral switch), etc, which may be opened and closed in response to a chopping signal (chopping pulse) CH
3
The stepup and rectifier circuit
21
(the rectifier circuit
21
in
FIG. 1
) includes a capacitor
123
for voltage stepup connected to the generator
20
, diodes
124
and
125
, and the switch
121
. The diodes
124
and
125
may be of any one-way element that allows a current to flow in one way, and the type thereof is not important. Since the electronically controlled mechanical timepiece, in particular, has a small electromotive-force generator
20
, a Schottky barrier diode having a small forward voltage Vf is preferred as the diode
125
. A silicon diode with a reverse leakage current thereof is preferred as the diode
124
.
A direct-current signal, rectified by the rectifier circuit
21
, charges a capacitor (power supply circuit)
22
.
The brake circuit
120
is controlled by a rotation controller
50
, which is an electronic circuit, driven by power supplied from the capacitor
22
. The rotation controller
50
includes an oscillator circuit
51
, a rotor rotation detector circuit
53
, and a brake control circuit
56
as shown in FIG.
1
and FIG.
2
.
The oscillator circuit
51
generates an oscillation signal (32768 Hz) using a crystal oscillator
51
A, i.e., a time standard source, and the oscillation signal is divided into a constant period through a frequency divider
52
having twelve stages of flipflops. An output Q
12
at a twelfth stage of the frequency divider
52
is output as an 8-Hz reference signal.
The rotation detector circuit
53
includes a wave shaping circuit
61
and a monostable multivibrator
62
, each connected to the generator
20
. The wave shaping circuit
61
is composed of an amplifier and a comparator, and converts a sine wave into a rectangular wave. The monostable multivibrator
62
functions as a bandpass filter that passes pulses having a predetermined period or shorter, and outputs a rotation detection signal FG
1
with noise removed therefrom.
The control circuit
56
includes an up/down counter
54
as brake control means, a synchronization circuit
70
, and a chopping signal generator
80
.
The up/down counter
54
respectively receives, at an up count input and a down count input thereof, the rotation detection signal FG
1
of the rotation detector circuit
53
and the reference signal fs from the frequency divider
52
, via the synchronization circuit
70
.
The synchronization circuit
70
is composed of four flipflops
71
and an AND gate
72
, and causes the rotation detection signal FG
1
to synchronize with the reference signal fs (8 Hz) using a fifth-stage output (1024 Hz) and a sixth-stage output (512 Qz) of the frequency divider
52
. The synchronization circuit
70
outputs these signal pulses in a manner such that they are not concurrently output.
The up/down counter
54
is composed of a 4-bit counter. The up/down counter
54
receives, at the up count input thereof, a signal based on the rotation signal FG
1
from the synchronization circuit
70
, and receives, at the down count input thereof, a signal based on the reference signal fs from the synchronization circuit
70
. With this arrangement, the up/down counter
54
concurrently counts the reference signal fs, the rotation signal FG
1
and the difference between the two counts.
The up/down counter
54
is provided with four data input terminals (preset terminals) A through D. Terminals A, B and Dare supplied with a high-level signal, setting the initial value (preset value) of the up/down counter
54
to count “11”.
Connected to the load input of the up/down counter
54
is an initializing circuit
91
, which is connected to the capacitor
22
, for outputting a system reset signal SR when power is initially fed to the capacitor
22
. The initializing circuit
91
outputs a high-level signal until the charged voltage of the capacitor
22
reaches a predetermined voltage, and then outputs a low-level signal when the predetermined voltage is reached.
The up/down counter
54
does not accept the up and down inputs until the load input, i.e., the system reset signal SR is transitioned to a low level, and the up/down counter
54
is maintained at a count of “11”.
The up/down counter
54
is provided with 4-bit outputs QA-QD. The third and fourth bits QC and QD output a high-level signal when the count is “12” or higher, and at least one of the third and fourth bits QC and QD necessarily outputs a low-level signal when the count is “11” or lower.
The output LBS of an AND gate
110
, to which outputs QC and QD are input, is a high-level signal when the up/down counter
54
gives the count of “12” or higher, and is a low-level signal when the up/down counter
54
gives the count of “11” or lower. The output LBS is connected to the chopping signal generator
80
.
The outputs of a NAND gate
111
and an OR gate
112
, each receiving the outputs QA-QD, are input to each of the NAND gates
113
, to which the outputs of the synchronization circuit
70
are also input. When the up count input signal is repeatedly input causing the count to reach “15”, the NAND gate
111
outputs a low-level signal. Then, if a further up count input signal is input to the NAND gate
113
, the input is canceled, and no further up count input signal afterward is input to the up/down counter
54
. Similarly, when the count reaches “0”, the OR gate
112
outputs a low-level signal, and a further down count input signal is canceled. In this way, the count is prevented from shifting “15” to “0”, or shifting from “0” to “15”.
The chopping signal generator
80
includes first chopping signal generating means
81
, constructed of three AND gates
82
-
84
, for outputting a first chopping signal CH
1
based on the outputs Q
5
-Q
8
of the frequency divider
52
, second chopping signal generating means
85
, constructed of two OR gates
86
and
87
, for outputting a second chopping signal CH
2
based on the outputs Q
5
-Q
8
of the frequency divider
52
, an AND gate
88
for receiving the output LBS of the up/down counter
54
and the output CH
2
of the second chopping signal generating means
85
, and a NOR gate
89
for receiving the output of the AND gate
88
and the output CH
1
of the first chopping signal generating means
81
.
The output CH
3
of the NOR gate
89
in the chopping signal generator
80
is input to the gate of the switch
121
constructed of a P-channel transistor. When the CH
3
is a low-level signal, the switch
121
is kept turned on, shorting the generator
20
for braking.
When the CH
3
is a high-level signal, the switch
121
is kept turned off, applying no brake on the generator
20
. The chopping signal from the output CH
3
thus controls the generator
20
in chopping control. The rotation controller
50
, including the chopping signal generator
80
outputting the chopping signal, opens or closes the switch
121
for chopping.
The rotation controller
50
is divided into an analog circuit
160
and a logic circuit
170
according to types as shown in FIG.
3
. The analog circuit
160
is driven by a power source VSS, and specifically includes part of the rotation detector circuit
53
that acquires information about the rotational status of the rotor from the generator
20
and the rectifier circuit
21
, and a circuit for controlling the rectifier circuit
21
. The information about the rotational status of the rotor, acquired by the rotation detector circuit
53
, is transferred to the logic circuit
170
.
The analog circuit
160
includes a constant voltage regulator
161
which is a power supply circuit for the logic circuit. The constant voltage regulator
161
is driven by the power source VSS, and outputs a constant voltage Vreg that is lower than the power source VSS. The constant voltage regulator
161
works as a power source for driving all circuits (the oscillator circuit
51
and the logic circuit
170
) other than the rectifier circuit
21
and the analog circuit
160
.
The logic circuit
170
includes a frequency divider and a variety of control circuits, and also includes the control circuit
56
that acquires information about the rotational status of the rotor, chiefly, from the analog circuit
160
to govern and control the generator
20
to rotate the rotor at a constant speed.
Each of the rotation detector circuit
53
and the control circuit
56
includes the analog circuit
160
and the logic circuit
170
.
The electronically controlled timepiece further includes an crown detector circuit
180
, which is an external control member detector circuit for detecting the pulled position of the crown, which is an external control member for switching between the normal mode and the hand setting mode. In the electronically controlled timepiece, the mainspring is ready to be tightened when the crown is turned. The crown is pulled in three steps, i.e., a zero step, a first step, and a second step. With the crown in the zero step, the timepiece is in a normal generating and hand driving state. With the crown in the first step, the timepiece is in a normal generating and hand driving state with the calendar ready to be corrected. With the crown in the third step, the rotor stops rotation with neither hand driving nor power generation carried out.
The crown detector circuit
180
includes a first signal line
183
for connecting the output of a first inverter
181
to the input of a second inverter
182
, a second signal line
184
for connecting the output of the second inverter
182
to the input of the first inverter
181
, and a selection switch
186
which connects the second signal line
184
to a signal input line
185
of the crown that is connected to the power source VDD when the crown is in the hand setting mode (in the second step), and which connects the first signal line
183
to the signal input line
185
when the crown is at another mode (in the zero step or the first step) other than the hand setting mode .
The first signal line
183
of the crown detector circuit
180
is connected to a power cutoff switch
162
, which is a switch for cutting off the supply of electrical energy to the analog circuit
160
, and a clock cutoff gate
171
, which is clock input limiting means for cutting off the clock input to the logic circuit
170
from the oscillator circuit
51
. The first signal line
183
is further connected to a reset terminal of the logic circuit
170
. With a low-level signal input at the reset terminal, the internal status of the logic circuit
170
is reset to the initial state thereof.
The power cutoff switch
162
remains on while the crown detector circuit
180
provides a high-level output, and remains off while the crown detector circuit
180
provides a low-level output. The clock cutoff gate
171
is composed of an AND gate, and directly feeds a clock signal from the oscillator circuit
51
to the logic circuit
170
when the crown detector circuit
180
provides a high-level output, and blocks the signal from the oscillator circuit
51
when the crown detector circuit
180
provides a low-level signal.
The operation of the present embodiment in the hand driving mode is discussed, referring to timing charts shown in FIG.
4
through
FIG. 6
, and a flow chart shown in FIG.
7
.
When the generator
20
starts operating, causing the initializing circuit
91
to output a low-level system reset signal SR to the load input of the up/down counter
54
(Step
31
, hereinafter simply referred to S rather than Step), the up count input signal based on the rotation signal FG
1
and the down count input signal based on the reference signal fs are counted by the up/down counter
54
as shown in
FIG. 4
(S
32
). These signals are adjusted through the synchronization circuit
70
so that they are not concurrently input to the up/down counter
54
.
When the up count input signal is input with the initial count of “11”, the count is shifted to “12”. The output LBS is driven high, and is output to the AND gate
88
in the chopping signal generator
80
.
When the down count input signal is input, causing the count to return to “11”, the output LBS is driven low.
In the chopping signal generator
80
, the first chopping signal generating means
81
gives the output CH
1
and the second chopping signal generating means
85
gives the output CH
2
, based on the outputs Q
5
-Q
8
of the frequency divider
52
, as shown in FIG.
5
.
When the up/down counter
54
outputs a low-level output LBS (with the count at “11” or lower), the output of the AND gate
88
is also at a low level. The output CH
3
of the NOR gate
89
is a chopping signal, which is an inverted CH
1
, having a duty factor (the ratio of turn on time of the switch
121
) of a long high-level duration (brake off time) and a short low-level duration (brake on time). The brake on time of the reference period becomes short, and practically, no brake is applied to the generator
20
. Specifically, the weak brake control with a priority placed on power generation is performed (S
33
and S
35
).
When the up/down counter
54
outputs a high-level output LBS (with the count at “12” or higher), the output of the AND gate
88
is also at a high level. The output CH
3
of the NOR gate
89
is a chopping signal, which is an inverted CH
2
, having a duty factor of a long low-level duration (brake on time) and a short high-level duration (brake off time). The brake on time of the reference period becomes long, and strong brake control is performed to the generator
20
. However, the brake off is repeated at regular intervals, permitting the chopper control, in which a reduction in generated power is controlled while braking torque is increased (S
33
and S
34
).
The stepup and rectifier circuit
21
stores charge generated by the generator
20
into the capacitor
22
. Specifically, the polarity of a first alternating-current terminal MG
1
is “−” while the polarity of a second alternating-current terminal MG
2
is “+”, and the voltage induced at the generator
20
charges a capacitor
123
having a capacitance of 0.1 μF, for instance.
On the other hand, the polarity of the first alternating-current terminal MG
1
becomes “+” while the polarity of the second alternating-current terminal MG
2
becomes “−”, and the sum of the voltage induced at the generator
20
and the charge voltage at the capacitor
123
charges the capacitor
22
.
At each of the above states, the generator
20
are shorted and then opened between the terminals thereof by the chopping pulse, inducing a high voltage across the terminals of the coil as shown in FIG.
6
. This high charge current charges the power supply circuit (capacitor)
22
, thereby increasing the charging efficiency.
When the torque of the mainspring
1
a
is large enough to rotate the generator
20
at a high rotational speed, a further up count input signal may be fed even after the up count signal raised the count to “12”. In such a case, the count rises to “13”, and the output LBS remains at a high level. The strong brake control is thus performed in which a brake is applied while being turned off at regular intervals by the chopping signal CH
3
. With a brake applied, the rotational speed of the generator
20
drops. If the reference signal fs (the down count input signal) is input twice before the entry of the rotation signal FG
1
, the count drops to “12”, and to “11”. At the moment the count drops to “11”, weak brake control is selected.
In such a brake control, the generator
20
reaches a set rotational speed, and the up count input signal and the down count input signal are alternately input to the up/down counter
54
, causing the count to alternate between “12” and “11” in a locked state as shown in FIG.
4
. In response to the count, the strong brake control and weak brake control alternate. Specifically, in one reference period during which the rotor makes one revolution, the chopping signal having a large duty factor and the chopping signal having a small duty factor are fed to the switch
121
to perform the chopping control.
The mainspring
1
a
is unwound, outputting a smaller torque, and the brake on time is gradually shortened. The rotational speed of the generator
20
becomes close to the reference speed even with no brake applied.
With no brake applied at all, the down count input signal is more frequently input. The count drops to a value of “10” or smaller, and the torque of the mainspring
1
a
is regarded as lowered. The hand is thus motionless or left moving at a very slow speed. A buzzer may be sounded, or a light may be lit to urge the user to tighten the mainspring
1
a.
While the up/down counter
54
outputs a high-level LBS signal, the strong brake control is performed using the chopping signal having a large duty factor. While the up/down counter
54
outputs a low-level LBS signal, the weak brake control is performed using the chopping signal having a small duty factor. Specifically, the up/down counter
54
as the brake control means switches between the strong brake control and the weak brake control.
In the embodiment, during the low-level LBS signal, the duty factor of the CH
3
chopping signal is 15:1 (high-level duration:low-level duration), namely, {fraction (1/16)}=0.0625. During the high-level LBS signal, the duty factor of the CH
3
chopping signal is 1:15 (high-level duration:low-level duration), namely, {fraction (15/16)}=0.9375.
Referring to
FIG. 6
, the generator
20
outputs, across MG
1
and MG
2
, an alternating current in response to the change in magnetic flux. Depending on the output LBS signal, the chopping signals CH
3
at a constant frequency but different duty factors are fed to the switch
121
. When the high-level LBS signal is output, namely, during the strong brake control, the short-circuit braking time in each chopper cycle is lengthened. The amount of braking increases, reducing the rotational speed of the generator
20
. As the amount of breaking increases, generated power is reduced, accordingly. However, energy accumulated during the short-circuit braking is output when the chopping signal turns off the switch
121
, and is used to step up the output voltage of the generator
20
. In this way, a reduction in generated power during the short-circuit braking is compensated for. The braking torque is thus increased while the reduction in generated power is restricted.
When the low-level LBS signal is output, namely, during the weak brake control, the braking time in the chopping cycle is shortened, increasing the rotational speed of the generator
20
. In this case, also, the chopping signal turns the switch
121
from on to off, and chopper voltage stepup results. The generated power is large compared with the generated power with no brake applied at all.
The alternating-current output of the generator
20
is stepped up and rectified through the voltage stepup and rectifier
21
, and charges the power supply circuit (capacitor)
22
, which in turn drives the rotation controller
50
.
The output LBS of the up/down counter
54
and the chopping signal CH
3
are commonly based on the outputs Q
5
-Q
8
and Q
12
of the frequency divider
52
. More specifically, the frequency of the chopping signal CH
3
is an integer multiple of the frequency of the output LBS, and the change in signal level of the output LBS, namely, a switch timing between the strong brake control and the weak brake control, takes place in synchronization with the chopping signal CH
3
.
Control of the time correction operation (hand setting operation) is performed in this embodiment as discussed below.
When the crown is pulled out from the normal hand driving position for the hand setting position, the control flow shown in
FIG. 8
is performed. Specifically, a storage register “pre_RYZ” for storing preceding crown position data is initialized (the value 3 is substituted) (S
1
). The value input at the initialization is any value other than the values set for representing the positions of the crown. For instance, when the crown positions are represented by two values “0” and “1”, 2 or larger number is acceptable. When three values “0”, “1”, and “2” are used, “3” or larger number may be used.
The crown position is detected (S
2
). The detection of the crown position is performed by the crown detector circuit
180
as described in the control flow shown in FIG.
9
.
When the crown is placed in the zero step or the first step, the switch
186
is connected to the first signal line
183
. Since the crown, namely, the switch
186
is connected to the power source VDD, a high-level signal is fed to the first signal line
183
. This signal is inverted through the second inverter
182
and the first inverter
181
as in “high low-Thigh”, and the output of the crown detector circuit
180
remains high. The status of the first signal line
183
is detected (S
21
), and a determination is made of whether the status is a high-level signal (S
22
). A high-level signal determines that the crown is placed in the zero step or in the first step, and the value “1” is entered into the storage register “now_RYZ” storing current crown position data (S
23
).
When the crown is placed in the second step, the switch
186
is connected to the second signal line
184
. The high-level signal from the power source VDD is inverted by the first inverter
181
into a low-level signal, which becomes the output of the crown detector circuit
180
. Since the low-level signal is inverted into a high-level signal by the second inverter
182
, the output signal of the crown detector circuit
180
remains low. The state of the first signal line
183
is detected (S
21
), and a determination is made of whether the state of the first signal line
183
is a high-level signal (S
22
). When the signal is found to be not high, namely, low, it is determined that the crown is placed in the second step, and the value “0” is entered to the storage register “now_RYZ” for the current crown position (S
24
).
Since the second signal line
184
is at a low level when the switch
186
is turned, the high-level signal and the low-level signal are shorted, allowing a short-circuit current to flow and consuming energy in vain. In this embodiment, the resistances of the inverters
181
and
182
are set to be large, making the current flowing therethrough to be small, and the short-circuit current taking place as a result of the short is minimized.
When the position of the crown is detected, a determination is made of whether pre_RYZ is larger than 1 (S
3
). When it is found that pre_RYZ is equal to or smaller than 1 (i.e., “0” or “1” as will be discussed later), a determination is made of whether pre_RYZ is equal to now_RYZ, in other words, whether the preceding position of the crown and the current position of the crown are the same (S
4
). If it is found that the preceding position and the current position are the same, a power supply control process to be discussed later is not necessary, and the control flow returns to the detection process of the crown (S
2
).
When it is found that pre_RYZ is not equal to now_RYZ (S
4
), or when it is found that pre_RYZ is larger than 1, in other words, the crown is pulled out from the normal hand driving mode and remains initialized (S
3
), the current crown position data now_RYZ overwrites the preceding crown position data pre_RYZ (S
5
).
A determination is made of whether new_RYZ is larger than “0” (S
6
) to determine the current crown position.
When it is found that now_RYZ is larger than “0”, namely, is “1”, with the crown placed in the zero step or the first step, the power cutoff switch
162
is turned on, causing power from the power source VSS to be supplied to the analog circuit
160
(S
7
). The clock signal from the oscillator circuit
51
is directly fed to the logic circuit
170
(S
8
). The normal hand driving control is thus performed, and the power generation is maintained. If the logic circuit
170
remains initialized, that state is released (S
9
).
On the other hand, when it is found that now_RYZ is “0”, i.e., the crown position is in the second step, the power cutoff switch
162
is turned off, cutting off power from the power source VSS to the analog circuit
160
(S
10
). The input of the clock signal from the oscillator circuit
51
to the logic circuit
170
is also cut off (S
11
). When the output of the crown detector circuit
180
is transitioned to an low-level signal, the internal status of the logic circuit
170
is reset, and the logic circuit
170
is initialized (S
12
).
However, the power supplying to the constant voltage regulator
161
is maintained, and the oscillator circuit
51
driven by the constant voltage regulator
161
remains operative.
The control flow returns to the crown position detection step (S
2
), and the above-discussed steps (S
2
through S
12
) are repeated.
During the hand setting operation, a mechanical mechanism stops the rotation of the rotor, the hands are not driven and power is not generated.
When the crown is pushed to the zero step or the first step subsequent to the hand setting operation, the crown detector circuit
180
outputs a high-level signal, closing the power cutoff switch
162
, and thereby driving the analog circuit
160
. Furthermore, the clock cutoff gate
171
conveys the clock signal from the oscillator circuit
51
. The initialized logic circuit
170
performs governing control on the rotor.
This embodiment provides the following advantages.
1) During the hand setting operation with the rotor suspended and no power generated, the power cutoff switch
162
, as a power source switch, suspends the supply of power to the analog circuit
160
. The clock cutoff gate
171
, as clock limiting means, cuts off the clock input to the logic circuit
170
, completely stopping the operation of the timepiece. The power consumption of the timepiece is thus reduced.
With this arrangement, the voltage drop across the power supply circuit (capacitor)
22
is restricted, and for a duration of time for the hand setting operation (3 to 5 minutes, for instance), the oscillator circuit
51
is continuously driven. When the crown is pushed in to resume power generation subsequent to the hand setting, the rotation controller
50
becomes operative immediately after the generator
20
starts generating in succession to the finish of the hand setting, because the oscillator circuit
51
has been continuously operated without any interruption. Unlike the conventional art, no time lag takes place before the oscillator circuit
51
becomes operative. No time indication error is caused from the hand setting operation to the resumption of time measurement. An accurate hand setting operation is thus carried out.
2) Since the crown detector circuit
180
, namely, an external control member detector circuit, is a logic circuit composed of the inverters
181
and
182
, the power consumption therethrough is reduced. The overall power consumption is made even smaller. Time before a voltage reduction takes place across the power supply circuit (capacitor)
22
is prolonged. The duration of time allowed for the hand setting operation is thus accordingly prolonged.
3) Since the resistances of the inverters
181
and
182
are set to be large to limit a short-circuit current, the power consumption through the crown detector circuit
180
is reduced more.
4) Since the logic circuit
170
is reset for initialization during the hand setting operation, control is usually started with the initial state when the generator
20
resumes the operation thereof subsequent to the finish of the hand setting operation. The governing control of the rotor is smoothly performed, correct control state is quickly resumed, and the creation of a time indication error is reliably prevented.
5) The rectifier circuit
21
steps up voltage through chopping, in addition to the voltage stepup through the use of the capacitor
123
, the direct-current output voltage of the rectifier circuit
21
, namely, the charge voltage of the capacitor
22
is thus increased.
A second embodiment of the present invention is now discussed, referring to FIG.
10
through FIG.
17
. In this embodiment, components identical to those described in connection with the preceding embodiment are designated with the same reference numerals and the discussion thereabout is omitted or briefly made.
Referring to
FIG. 10
, the electronically controlled mechanical timepiece, which is the electronically controlled timepiece of this invention, includes a mainspring
1
a
as a mechanical energy source, accelerating train wheels (series of wheels)
7
as mechanical energy transmission means for transmitting torque of the mainspring
1
a
to a generator
20
, and a hand
13
, as a time display unit for indicating time, connected to the accelerating train wheels
7
.
The generator
20
is driven by the mainspring
1
a
via the accelerating train wheels
7
, and generates an electromotive force to supply electrical energy. The alternating-current output from the generator
20
is rectified by a rectifier circuit
21
, which has at least one of the functions of stepup and rectification, full-wave rectification, half-wave rectification, and transistor rectification, and is stepped up as required. The alternating-current voltage is then fed to a power supply circuit
22
as a power source such as a capacitor to charge it.
The generator
20
is governed and controlled by the rotation controller
50
. The rotation controller
50
includes an oscillator circuit
51
, a rotor rotation detector circuit
53
, and a brake control circuit
56
, and the construction thereof remains unchanged from that of the first embodiment as shown in FIG.
11
.
The oscillator circuit
51
generates an oscillation signal (32768 Hz) using a crystal oscillator
51
A, a time standard source, and the oscillation signal is divided into a constant period through a frequency divider and is output as a reference signal fs.
The rotation detector circuit
53
is composed of a wave shaping circuit connected to the generator
20
, and converts the alternating-current output from the generator
20
into a rectangular wave, and outputs as a rotation detection signal FG
1
with noise removed therefrom.
The control circuit
56
compares the rotation detection signal FG
1
with the reference signal fs, thereby setting the amount of braking, and applying a brake on the generator
20
to govern it.
Specifically, the rotation controller
50
includes a drive circuit
57
composed of a drive IC for driving the oscillator circuit
51
as shown in FIG.
12
. Like the constant voltage regulator
161
in the first embodiment shown in
FIG. 3
, the drive circuit
57
drives the oscillator circuit
51
and the logic circuit. The drive circuit
57
is driven by power (power source VSS) from the power source capacitor
22
as the power supply circuit, and outputs a constant level voltage Vreg lower than the power source VSS. A switch
261
, which is a power supply control unit, controls the supply of power from the power source capacitor
22
to the drive circuit
57
.
In the electronically controlled timepiece of this embodiment, the crown can be pulled out in three steps, wherein in a zero step, the mainspring is tightened by turning the crown with the hands turning and the generator generating, and in a first step, a calendar is corrected by turning the crown with the hands turning and the generator generating, and in a second step, time correction is performed by turning the crown with the rotor stopping moving, the hands motionless, and the generator not generating. The switch
261
is closed with the crown placed in the first or zero step, and is opened with the crown placed in the second step. In other words, the switch
261
is a mechanically driven switch that operates in interlock with the time correction operation.
A switch
262
is connected to the drive circuit
57
. The switch
262
is a mechanically driven switch which operates in interlock with the switch
261
, and is used to input a crown position signal to the drive circuit
57
. Specifically, the switch
261
is closed with the crown placed in the zero or first position, and the switch
262
is connected to a zero and first step circuit in interlock with the switch
261
. With the crown placed in the second step, the switch
261
is opened, and the switch
262
is connected to a second step circuit. Recognizing the signal from these circuits, the drive circuit
57
performs timepiece control, for instance, performing normal hand driving control with the crown in the zero or first step, and setting or resetting a counter and system initialization with the crown in the second step.
A second capacitor
25
, connected in parallel with the capacitor
22
, is arranged between the capacitor
22
and the drive circuit
57
. The second capacitor
25
is smaller in capacitance than the capacitor
22
. The capacitance of the capacitor
22
falls within a range from 1 to 15 μF, and is typically 10 μF or so. The capacitance of the second capacitor
25
falls within a range from 0.05 to 0.5 μF, and is typically 0.1 μF. With the second capacitor
25
included, the supply of power to the IC (the drive circuit
57
) is continuously made to prevent the IC from being shut down even if the switch
261
is momentarily disengaged due to vibrations or shocks, thereby disconnecting the first capacitor
22
from the IC.
The brake control circuit
56
includes an indication error corrector unit
200
. Referring to
FIG. 13
, the indication error corrector unit
200
includes a temperature sensor
201
, such as a water-temperature sensor or an infrared temperature sensor, a voltage detector
202
, such as a comparator for detecting a voltage across the capacitor
22
, A/D (analog-to-digital) converters
203
and
204
for converting measurement values provided by the temperature sensor
201
and the voltage detector
202
, initial value setting means
205
, which is a correction value setter for setting, for the up/down counter
54
, an initial value that accounts for the output values of the converters
203
and
204
, and a latch
207
that latches the data output by the initial value setting means
205
.
Referring to
FIG. 14
, the initial value setting means
205
includes an initial value setting table
206
which sets the correspondence between the output values of the temperature sensor
201
and the voltage detector
202
(specifically, the output values of the A/D converters
203
and
204
) and the initial value of the up/down counter
54
. Each of the A/D-converters
203
and
204
gives a 5-bit output, namely an output graduated at 32 steps within a range from zero to 32. The initial value setting table
206
divides the outputs of the A/D converters
203
and
204
at six gradations, and sets, in the up/down counter
54
, an initial value corresponding to the output.
The initial value setting means
205
is connected to four data input terminals (preset terminals) A-D of the up/down counter
54
via the latch
207
. The up/down counter
54
is supplied with the initial value by inputting a high-level signal or a low-level signal thereto in accordance with the initial value set by the initial value setting table
206
.
The A/D converters
203
and
204
, the initial value setting means
205
, and the latch
207
are designed to respond to a variation in the crown position that takes place when the crown is pulled out or pushed in, namely, to a variation in a system reset signal (SR or a trigger signal).
In this embodiment, the generator
20
is controlled by the rotation controller
50
during the normal hand driving mode in the same way as in the first embodiment. Furthermore, during the normal hand driving mode, i.e., with the crown placed in the zero step or the first step, the current generated by the generator
20
charges the capacitor
22
through the rectifier circuit
21
.
The voltage applied to the drive circuit
57
is equal to the voltage of the capacitor
22
, namely, about 1.0 V as shown in FIG.
15
.
Control during the time correction operation (hand setting operation) is performed as discussed below.
When the crown is pulled out to the second step from the normal hand driving position for the hand setting operation, the switch
261
is opened in interlock with the pull of the crown (point A in FIG.
15
). At the same time, the generator
20
stops. Since the second capacitor
25
is used in this embodiment, power is supplied by the second capacitor
25
immediately subsequent to the stop of the generator
20
. Because the capacitance of the second capacitor
25
is small, the voltage thereacross is rapidly reduced by the load of the drive circuit
57
. When the voltage across the second capacitor
25
, namely, the voltage applied to the drive circuit
57
, drops below the voltage Vstop (approximately 0.6 V), the drive circuit
57
, namely, the oscillator circuit
51
stops.
With the switch
261
opened, almost no power of the capacitor
22
is consumed, and the voltage of the capacitor
22
is maintained at a voltage of about 1.0 V.
When the crown is pushed in to the first step with the hand setting operation completed, the switch
261
is closed (point B in FIG.
15
). Electrical energy is then fed to the drive circuit
57
from the capacitor
22
, which has been maintained at a voltage of about 1.0 V, and the oscillator circuit
51
restarts operating.
Since the oscillator circuit
51
is supplied with a voltage as high as 1.0 V as shown
FIG. 16
, time Tstart prior to the start of oscillation (corresponding to time T
2
in the-conventional art shown in
FIG. 26
) is substantially shortened to about 0.8 second (at an ambient temperature of 25° C.). Since the time T
1
needed prior to the voltage rise of the capacitor
22
in the conventional art is eliminated, the time to the operation of the oscillator circuit
51
subsequent to the hand setting operation is substantially shortened.
When the oscillator circuit
51
operates, the control circuit
56
brake controls the generator
20
. The initial value of the up/down counter
54
in the control circuit
56
is set by the indication error corrector unit
200
.
Upon detecting the push of the crown, the A/D converters
203
and
204
in the indication error corrector unit
200
outputs, to the initial value setting means
205
, values corresponding to the measurement values provided by the temperature sensor
201
and the voltage detector
202
. For instance, as shown in
FIG. 17
, when the temperature measured by the temperature sensor
201
falls within a range equal to or higher than 0° C. and lower than 4° C., the A/D converter
203
outputs a value “10”. When the temperature measured by the temperature sensor
201
falls within a range equal to or higher than 4° C. and lower than 8° C., the A/D converter
203
outputs a value “11”. In this way, the output of the A/D converter
203
changes in a stepwise fashion by temperature steps of4° C. Similarly, when the voltage measured by the voltage detector
202
falls within a range equal to or higher than 0.8 V and lower than 0.82 V, the A/D converter
204
outputs a value “10”. When the voltage measured by the voltage detector
202
falls within a range equal to or higher than 0.82 V and lower than 0.82 V, the A/D converter
204
outputs a value “11”. In this way, the output of the A/D converter
204
changes in a stepwise fashion by voltage steps of 0.02 V.
The initial value setting table
206
sets the initial value in accordance with the oscillation start time Tstart, namely, the output values of the converters
203
and
204
. When the oscillation start time is short, the control circuit
56
is driven quickly subsequent to the time correction operation, and a correction value of “0” may be acceptable. A standard initial value (“11” ) may be set as the initial value of the up/down counter
54
. Specifically, as shown in
FIG. 16
, as the voltage of the capacitor
22
is higher, and as temperature is higher, the oscillation start time becomes shorter. When the values from the converters
203
and
204
are large, an initial value of “11” is set.
When the oscillation start time is longer, more time is needed before the control circuit
56
is driven, and the time with no brake control performed on the generator
20
is prolonged. In this embodiment, the mainspring
1
a
outputs torque sufficient enough to allow the generator
20
to rotate at a speed higher than the reference period of the generator
20
. With a brake applied, the generator
20
is governed to the reference period. If the time with no brake control performed is prolonged, the rotation period of the generator
20
becomes shorter than the reference period. For this reason, the longer the time to the start of the oscillation, the stronger braking is applied to reduce the rotational speed.
As in the first embodiment, strong brake control is performed with the output of the up/down counter
54
at “12” or larger, and weak brake control is performed with the output of the up/down counter
54
at “11” or smaller. By setting a large initial value to the up/down counter
54
(“15” at maximum), the time of the strong brake control is prolonged. As the voltage of the capacitor
22
is lower and as temperature is lower, the oscillation start time becomes longer. Therefore, as the output values of the converters
203
and
204
become smaller, the initial values set become larger to “11”, “12”, “13”, “14”, and then to “15”.
Correction responsive to the time to the start of the oscillation of the oscillator circuit
51
is performed during the brake control by the control circuit
56
. As a result, the position of the hand is corrected to no slow nor fast time state (with zero indication error), and the indication error is eliminated.
When the generator
20
starts, reverting back to the normal operation, power from the generator
20
is fed to the drive circuit
57
through the capacitor
22
, and the generator
20
is continuously subjected to rotation control.
This embodiment provides the following advantages.
(2-1) Since the timepiece includes the power supply control unit which is composed of the switch
261
and is opened and closed in response to the push and pull of the crown, namely, the time correction operation, no power is supplied to the rotation controller
50
from the capacitor (power supply circuit)
22
during the suspension of the generator
20
with the crown pulled out, and the capacitor
22
maintains the terminal voltage thereacross.
The capacitor
22
thus supplies power to the rotation controller
50
immediately subsequent to the start of the generator
20
after the time correction operation. There occurs no time lag (time T
1
) until the voltage of the power source for the drive circuit (drive IC)
57
rises to be high enough to start oscillating, and the duration of time during which the rotation control of the rotor is not performed is shortened, and the hand indication error is thus minimized.
(2-2) Since the switch
261
disconnects the capacitor
22
from the drive circuit
57
, the voltage across the capacitor
22
is maintained at a relatively high level (about 1.0 V, for instance) With this arrangement, the drive circuit
57
is supplied with a high voltage when the switch
261
is closed. The time (Tstart) until the oscillation of the oscillator circuit
51
in the rotation controller
50
is thus shortened. The rotation controller
50
becomes operative more rapidly, reducing the indication error.
(2-3) Since the timepiece includes the control circuit
56
having the indication error corrector unit
200
, an indication error, if any, is corrected, and the indication error is reduced more, or almost removed.
(2-4) The indication error corrector unit
200
detects the voltage applied to the capacitor
22
, namely, the oscillator circuit
51
, and the temperature of the oscillator circuit
51
, both affecting the oscillation start time of the oscillator circuit
51
, to set the correction value (the initial value at the up/down counter
54
). The correction is thus precisely performed, and the indication error is substantially minimized. Since the indication error is corrected by detecting not only the voltage applied to the oscillator circuit
51
but also temperature thereof to adjust the correction values, the accuracy level of the correction values is improved, and the indication error is further corrected. The indication error is minimized, particularly when the timepiece is used in cold areas with the temperature of the oscillator circuit
51
low, or when the timepiece is exposed to sunlight or is used in hot areas with the temperature of the oscillator circuit
51
high.
(2-5) The indication error corrector unit
200
corrects the indication error by simply changing the initial value at the up/down counter
54
. Compared with the arrangement in which the correction is made by adding a correction value to the output value of the up/down counter
54
, the indication error is corrected using a simple arrangement, and costs involved are reduced.
(2-6) The switch
261
, namely, the power supply control unit, is a mechanically driven switch that operates in interlock with the pull operation of the crown. The switch
261
thus has a simple construction, and the electronically controlled mechanical timepiece is manufactured at low costs. It is sufficient if the switch
261
is merely added. An increase in the manufacturing cost is minimal, and the timepiece is supplied for a relatively low cost, compared with the conventional art.
(2-7) The second low-capacitance capacitor
25
is arranged, besides the capacitor
22
. Even when the switch
261
suffers from chattering, the capacitor
25
feeds power to the drive circuit
57
, and the drive circuit
57
is prevented from being shut down as a result of chattering.
(2-8) Since an excessively large capacitance is not required of the capacitor
22
, the capacitor
22
is charged with the voltage thereof rapidly increasing from a state of no charge stored, within a short time.
Since a large generation capacity is not required of the generator
20
, the sizes of the generator
20
and the mainspring la are made compact. This arrangement finds application in wristwatches, which are subject to the limitation of area and thickness dimensions.
Next, a third embodiment of the present invention is now discussed, referring to FIG.
18
through FIG.
21
. In this embodiment, components identical or similar to those described in connection with the preceding embodiments are designated with the same reference numerals and the discussion thereabout is omitted here.
FIG. 18
is a block diagram showing an electronically controlled mechanical timepiece, which is the electronically controlled timepiece of this invention.
The electronically controlled mechanical timepiece includes a mainspring
1
a
as a mechanical energy source, accelerating train wheels (series of wheels)
7
as mechanical energy transmission means for transmitting torque of the mainspring
1
a
to a generator
20
, and a hand
13
, as a time display unit for indicating time, connected to the accelerating train wheels
7
.
The generator
20
is driven by the mainspring
1
a
via the accelerating train wheels
7
, and generates an electromotive force to supply electrical energy. The alternating-current output from the generator
20
is rectified by a rectifier circuit
21
, which has at least one of the functions of stepup and rectification, full-wave rectification, half-wave rectification, and transistor rectification, and is stepped up as required. The alternating-current voltage is then fed to a power supply circuit
30
as a power source such as a capacitor to charge it.
The generator
20
is governed and controlled by the rotation controller
50
. The rotation controller
50
includes an oscillator circuit
51
, a rotor rotation detector circuit
53
, and a brake control circuit
56
, and the construction thereof remains unchanged from that of the first embodiment.
The oscillator circuit
51
generates an oscillation signal (32768 Hz) using a crystal oscillator
51
A, i.e., a time standard source, and the oscillation signal is divided into a constant period through a frequency divider and is output as a reference signal fs.
The rotation detector circuit
53
is composed of a wave shaping circuit connected to the generator
20
, and converts the alternating-current output from the generator
20
into a rectangular wave, and outputs as a rotation detection signal FG
1
with noise removed therefrom.
The control circuit
56
compares the rotation detection signal FG
1
with the reference signal fs, thereby setting the amount of braking, and applying a brake on the generator
20
to govern it.
Specifically, the rotation controller
50
includes a drive circuit
57
composed of a drive IC for driving the oscillator circuit
51
as shown in FIG.
19
. The drive circuit
57
is driven by power from a main capacitor
31
(a main storage unit) forming the power supply circuit
30
. The main capacitor
31
ranges from 0.05 to 0.5 μF in capacitance, and is typically a ceramic capacitor having a capacitance of about 0.2 μF. The main capacitor
31
smoothes the current from the generator
20
to feed power to the rotation controller
50
.
An auxiliary capacitor (an auxiliary storage unit)
32
, having a capacitance larger than that of the capacitor
31
, is connected in parallel with the main capacitor
31
. The auxiliary capacitor
32
ranges from 1 to 15 μF in capacitance, and typically has a capacitance of about 10 μF.
A mechanically driven switch
361
is arranged between the capacitors
31
and
32
. In the electronically controlled mechanical timepiece of this embodiment, the crown can be pulled out in three steps, wherein in a zero step, the mainspring is tightened by turning the crown with the hands turning and the generator generating, and in a first step, a calendar is corrected by turning the crown with the hands turning and the generator generating, and in a second step, time correction is performed by turning the crown with the rotor stopping moving, the hands motionless, and the generator not generating. The switch
361
is closed with the crown placed in the first or zero step, and is opened with the crown placed in the second step. In other words, the switch
361
is a mechanically driven switch that operates in interlock with the time correction operation.
A switch
262
is connected to the drive circuit
57
. The switch
262
is a mechanically drive switch that operates in interlock with the switch
361
, and is used to input a crown position signal to the drive circuit
57
. Specifically, the switch
361
is closed with the crown placed in the zero or first position, and the switch
262
is connected to a zero and first step circuit in interlock with the switch
361
. With the crown placed in the second step, the switch
361
is opened, and the switch
262
is connected to a second step circuit. Recognizing the signal from the these circuits, the drive circuit
57
performs timepiece control, for instance, performing normal hand driving control with the crown in the zero or first step, and setting or resetting a counter and system initialization with the crown in the second step.
A charge control circuit
35
, composed of a diode
36
and a resistor
37
in parallel connection, is connected between the capacitors
31
and
32
. A diode having a smaller forward voltage Vf (0.2 V, for instance) is preferable for the diode
36
, and a Schottky barrier diode may be used. The diode
36
is configured so that the diode
36
is aligned opposite to the direction of the charging current (from VDD to VSS) when the capacitors
31
and
32
are charged by the rectifier circuit
21
, namely, by the generator
20
, with the switch
361
closed, and is aligned with the direction of the current flowing from the auxiliary capacitor
32
to the main capacitor
31
.
The resistance of the resistor
37
is preferably large, and is 100 MΩ in this embodiment.
The power supply circuit
30
is composed of the main capacitor
31
, the auxiliary capacitor
32
, the charge control circuit
35
(the diode
36
and the resistor
37
), and the switch
361
.
In this embodiment, the normal hand driving is controlled in the same manner as in the first embodiment. Specifically, during the normal hand driving mode, i.e., with the crown placed in the zero step or the first step, the current generated by the generator
20
charges the capacitors
31
and
32
through the rectifier circuit
21
, because the switch
361
is closed. Because of its small capacitance, the capacitor
31
tends to vary in voltage due to variations in the voltage of the generator
20
and the load of the drive circuit
57
. But a large-capacitance auxiliary capacitor
32
connected in parallel therewith backs up, thereby maintaining the voltage constant (approximately 1.0 V).
The voltage applied to the drive circuit
57
(the voltage of the main capacitor
31
) is maintained at the same level as that of the auxiliary capacitor
32
as shown in FIG.
20
.
Control during the time correction operation (hand setting operation) is performed as follows.
When the crown is pulled out to the second step from the normal hand driving position for the hand setting operation, the switch
361
is opened in interlock with the pull of the crown (point A in FIG.
20
). With the switch
361
opened, almost no power of the auxiliary capacitor
32
is consumed, and the voltage of the capacitor
32
is maintained at a voltage of about 1.0 V.
During the hand setting operation, the generator
20
stops rotating, allowing no charging current to flow into the main capacitor
31
. The voltage of the main capacitor
31
rapidly drops by the load of the drive circuit
57
. When the voltage of the main capacitor
31
becomes equal to or lower than the voltage Vstop (approximately 0.6 V), the drive circuit
57
stops operating.
When the crown is pushed in to the first step after the hand setting operation, the switch
361
is closed (point B in FIG.
20
). A current flows into the main capacitor
31
through the diode
36
from the auxiliary capacitor
32
that is held at a voltage of approximately 1.0 V. Because of a small capacitance thereof, the main capacitor
31
reaches the same voltage (1.0 V) as that of the auxiliary capacitor
32
, and feeds electrical energy to the drive circuit
57
, thereby causing the oscillator circuit
51
to start operating.
Since the oscillator circuit
51
is supplied with a high voltage of 1.0 V as in the second embodiment as shown in
FIG. 16
, the time Tstart prior to the start of the oscillation (corresponding to the time T
2
in the conventional art shown in
FIG. 26
) is shortened to be approximately 0.8 second (at a temperature of about 20° C.). The duration of time from the push of the crown (point B in
FIG. 20
) to the voltage of the main capacitor
31
reaching 1.0 V is very short, and thereby the time the oscillator circuit
51
takes to start operating subsequent to the hand setting operation is substantially shortened.
When the hand setting operation takes
10
minutes or longer, or when the voltage of the auxiliary capacitor
32
is zero V or in the vicinity of zero V. (down to point C in
FIG. 21
) with the timepiece left unattended for a long period of time, the main capacitor
31
is also held at almost zero V.
When the switch
361
is closed after the hand setting operation, setting the generator
20
operative (point C in FIG.
21
), a major percentage of the current flows into the main capacitor
31
rather than into the auxiliary capacitor
32
. Specifically, the diode
36
blocks the charging current of the generator
20
flowing to charge the auxiliary capacitor
32
, and the resistor
37
is as high as 100 MΩ. A major percentage of the generated current thus flows into the main capacitor
31
and almost no current flows into the auxiliary capacitor
32
. The generator
20
is designed to result in a current within a range from about 100 nA to several 10 μA with the capacitors
31
and
32
in the vicinity of zero V, and an extremely small current flowing through the resistor
37
is neglected.
The voltage of the main capacitor
31
rapidly rises with the major percentage of the generated current flowing thereinto. Along with this, the main capacitor
31
reaches the oscillation start voltage (Vstart) of the drive circuit
57
(IC) within a short time (approximately 1.5 seconds, for instance) subsequent to the hand setting operation, and the control starts. If no charge control circuit
35
were employed with the current generated by the power supply circuit
30
flowing to both capacitors
31
and
32
, the main capacitor
31
would take about 15 seconds to reach the oscillation start voltage of the drive circuit
57
. In this embodiment, the main capacitor
31
reaches the oscillation start voltage within one-tenth the time.
After the drive circuit
57
starts driving, a charging current gradually flows into the auxiliary capacitor
32
through the resistor
37
. After a sufficiently long period of time has passed, the auxiliary capacitor
32
reaches the same voltage as that of the main capacitor
31
(approximately 1.0 V).
In the normal hand driving state, the auxiliary capacitor
32
serves as a backup for the main capacitor
31
in the event of voltage fluctuations, contributing to stabilizing the power source voltage and the system operation.
The oscillator circuit
51
substantially remains constant at a voltage of approximately 1.0 and the time Tstart to the oscillation is also constant at about 0.8 second, when the auxiliary capacitor
32
holds charge. The control circuit (the brake control circuit)
56
performs brake control by applying a constant quantity correction corresponding to a predetermined value (approximately 0.8 second, for instance) to further reduce the indication error.
When the auxiliary capacitor
32
holds no charge, the voltage applied to the oscillator circuit
51
gradually rises from about 0.7 V, and the time Tstart to the oscillation is substantially constant with about 1.5 seconds (the time required for the main capacitor
31
to rise to Vstart=0.7 V)+20 seconds (the time the oscillator circuit
51
takes to start oscillating when a voltage of 0.7 V is applied thereto). The control circuit
56
performs brake control by applying a constant quantity correction corresponding to a predetermined value (approximately 21.5 seconds, for instance) to further reduce the indication error.
The selection between these correction values is determined by detecting the voltage value applied to the control circuit
56
and the rotation period of the generator
20
. Available as a method of setting the correction value is the method of counting time set in a timer or the method of setting a timer in an analog fashion using a CR time constant.
When the generator
20
becomes operative, performing the normal operation, power from the generator
20
is fed to the drive circuit
57
via the main capacitor
31
. The rotation control of the generator
20
is thus continuously performed.
This embodiment provides the following advantages.
(3-1) The charge control circuit, composed of passive elements such as the diode
36
and the resistor
37
, is employed to control the charging and discharging of the main capacitor
31
and the auxiliary capacitor
32
, and compared to the conventional art which employs the comparator, i.e., an active element, power consumption is reduced.
With the comparator dispensed with, the ability of the generator
20
is reduced accordingly. Since a reduced energy supply from the mainspring
1
a
works, time of sustaining energy supply from the fully tightened state of the mainspring
1
a
is thus prolonged. With the size of the generator
20
reduced, the component layout is facilitated within a timepiece body having limited space, and as a result, the timepiece itself is reduced in size. This arrangement finds application in wristwatches, which are subject to the limitation of area and thickness dimensions.
(3-2) The timepiece includes the switch
361
, which is opened and closed in response to the push and pull of the crown. When the generator
20
is stopped with the crown pulled out, the auxiliary capacitor
32
supplies no power to the rotation controller
50
, and maintains the terminal voltage thereacross.
The auxiliary capacitor
32
feeds a current to the main capacitor
31
, namely, the rotation controller
50
immediately subsequent to the start of the generator
20
after the hand setting operation. This embodiment is free from a time lag of the conventional art, i.e., the time lag before the voltage of the power source of the drive circuit (the drive IC)
57
rises high enough to start oscillation. The duration of time, during which the rotation control of the rotor is not performed, is shortened, and the indication error is minimized. The present invention thus assures both the startup capability subsequent to the hand setting and the accuracy of the hand setting at the same time.
When the auxiliary capacitor
32
charges the main capacitor
31
, the charging current flows through the diode
36
, with a charging loss involved.
(3-3) Since the switch
361
disconnects the auxiliary capacitor
32
from the drive circuit
57
, the auxiliary capacitor
32
is maintained at a relatively high voltage (about 1.0 V, for instance). When the switch
361
is closed, the drive circuit
57
is supplied with the high voltage, shortening the time (Tstart) until the oscillator circuit
51
in the rotation controller
50
starts oscillating. The rotation controller
50
is even more rapidly operated, reducing the indication error.
(3-4) A small-capacitance main capacitor
31
is employed, and the charge control circuit
35
is arranged to allow more charging current from the generator
20
to flow into the main capacitor
31
, when no charge is stored in the capacitors
31
and
32
, for instance, after the timepiece has been left unattended for a long period of time. The time, the main capacitor
31
takes to reach the voltage capable of driving the drive circuit
57
from a zero-volt state thereof, is shortened approximately one-tenth the time required when no charge control circuit
35
is employed. After being left unattended for a long period of time, the present invention thus assures both the startup capability subsequent to the hand setting and the accuracy of the hand setting at the same time.
If the drive circuit
57
is not driven after the hand setting, and no brake is applied on the hand driving at all in a free running state, the second hand moves fast, and the user may have anxiety about and lose confidence in the timepiece. In this embodiment, the drive circuit
57
resumes the driving operation within a short time. There is almost no time during which the second hand moves fast, and the user's confidence in the timepiece is thus maintained.
(3-5) The main capacitor
31
is directly connected to the drive circuit
57
, not by way of the mechanically driven switch
361
. Even if the mechanically driven switch
361
chatters, the main capacitor
31
continuously feeds power to the drive circuit
57
, thereby preventing the drive circuit
57
from being shut down as a result of chattering.
(3-6) Since the auxiliary capacitor
32
, having a capacitance larger than that of the main capacitor
31
, is connected in parallel with the main capacitor
31
, the auxiliary capacitor
32
may back up the main capacitor
31
in the event of voltage fluctuations, contributing to stabilizing the power source voltage and the system operation.
(3-7) Although the time until the drive circuit
57
starts driving subsequent to the hand setting operation becomes different depending on whether the auxiliary capacitor
32
holds charge, the time is controlled to a substantially constant. The indication error is corrected by performing a constant quantity correction using a predetermined value. The indication error is thus minimized, and the accuracy of the hand setting is even further improved.
(3-8) The charge control circuit
35
is composed of low-cost elements, such as the diode
36
and the resistor
37
. Compared to the arrangement using a comparator, the manufacturing costs are reduced, and a low-cost timepiece is thus supplied.
(3-9) The control of the charging current to the capacitors
31
and
32
through the charge control circuit
35
is performed by selecting a proper resistance for the resistor
37
. Depending on the type of a timepiece, a proper resistance value may be selected.
(3-10) The indication error is corrected through the constant quantity correction control using a predetermined value. The construction of the indication error corrector unit (control circuit)
56
is thus simplified and the cost thereof is accordingly reduced.
A fourth embodiment of the present invention is now discussed, referring to FIG.
22
.
In this embodiment, the charge control circuit
35
is constructed of only a diode
38
having a reverse leakage current. In this case, when the generator
20
charges the capacitors
31
and
32
, the charging current to the auxiliary capacitor
32
becomes extremely small because the charging current is the reverse leakage current of the diode
38
only. A major percentage of the charging current flows into the main capacitor
31
. In the same way as in the preceding embodiment, the main capacitor
31
rapidly rises in voltage, thereby shifting the drive circuit
57
into a control state within a short period of time.
When the auxiliary capacitor
32
holds charge, the auxiliary capacitor
32
feeds a current to the main capacitor
31
through the diode
38
. The drive circuit
57
is rapidly driven, with a small current loss involved.
Besides the advantages (3-1) through (3-9) of the third embodiment, the fourth embodiment enjoys a cost reduction, because the diode
38
only is used for the charge control circuit
35
.
A fifth embodiment of the present invention is now discussed, referring to
FIGS. 23 and 24
. This embodiment includes the indication error corrector unit
200
in the second embodiment in the control circuit
56
in the third embodiment.
When the switch
361
is closed with the auxiliary capacitor
32
holding charge after the time correction operation, the auxiliary capacitor
32
charges the main capacitor
31
by feeding a current to the main capacitor
31
through the diode
36
, thereby very quickly driving the drive circuit
57
. In the same way as in the second embodiment, when the drive circuit
57
is driven, the indication error corrector unit
200
performs brake control on the generator
20
taking into account the correction values that account for the oscillation start time and temperature. The indication error is thus removed.
When the switch
361
is closed with the auxiliary capacitor
32
holding no charge, a major percentage of the charging current flows into the main capacitor
31
by way of the charge control circuit
35
. In the same way as in the preceding embodiment, the main capacitor
31
rapidly rises in voltage, shifting the drive circuit
57
into a control state within a short period of time. In this case, as well, the indication error is removed, because the indication error corrector unit
200
corrects brake control for the generator
20
.
This embodiment enjoys the advantages (2-3) through (2-5) provided by the use of the indication error corrector unit
200
in the second embodiment and advantages (3-1) through (3-9) in the third embodiment.
The present invention is not limited to the above embodiments, and changes and modifications, within which the object of the present invention is achieved, fall within the scope of the present invention.
In the first embodiment, for instance, the power source switch (the power cutoff switch
162
) is arranged in the power source VSS. Alternatively, the power source switch may be arranged on the power source VDD or may be arranged on each of the power sources VDD and VSS. It is important that the power source switch cuts off the supply of electrical energy to the analog circuit
160
to reduce the power consumption, and the position of and the construction of the power source switch may be arbitrarily set.
The power source switch (the power cutoff switch
162
) is not limited to the one that is driven by a signal from the crown detector circuit
180
. The power source switch may be a mechanically driven switch that operates in interlock with the operation of the crown. Alternatively, the power source switch may be opened and closed in interlock with the stop and activation of the generator
20
or the train wheels. It is important that the power source switch be opened and closed in interlock with the hand setting operation.
The clock input limiting means (the clock cutoff gate
171
) is not limited to the AND gate in the first embodiment. Alternatively, the clock input limiting means may be a switch that connects or disconnects the signal line between the oscillator circuit
51
and the logic circuit
170
. It is important that the clock input limiting means block the clock input to the logic circuit
170
.
Unlike the first embodiment, the selection switch
186
in the crown detector circuit
180
is configured so that the second signal line
184
is connected to the zero and first steps and that the first signal line
183
is connected to the second step. In this case, the output signal of the crown detector circuit
180
is inverted, and the power cutoff switch
162
and the clock cutoff gate
171
need to be configured in accordance with the output signal.
The signal input line
185
of the crown is connected to the power source VDD in the first embodiment. Alternatively, the signal input line
185
is connected to the power source VSS side. In this case, the crown detector circuit
180
is configured so that the crown position may be detected by the closing of the switch
186
connected to the power source VSS.
The switch
186
may be configured to continuously connect to the signal line
183
or
184
with the crown placed in each step. With the two inverters
181
and
182
thereof, the crown detector circuit
180
sustains the signal input from the switch
186
. The switch
186
may be instantaneously put into contact with one of the signal lines
183
and
184
when the crown is switched, and may be held in an intermediate position remaining unconnected to any of the signal lines
183
and
184
until the crown is switched next.
The external control member detector circuit (the crown detector circuit
180
) is not limited to the construction of the preceding embodiments. The external control member detector circuit may be a conventional crown detector circuit shown in FIG.
28
. The use of the crown detector circuit
180
of the preceding embodiments further reduces power consumption.
The external control member for switching between the hand setting mode and the normal hand driving mode is not limited to the crown, and may be a dedicated button or lever. The external control member may be a mechanically driven one or an electrical one. A suitable control member may be selected. Furthermore, the external control member detector circuit is not limited to the one for detecting the voltage as in the preceding embodiments. The external control member detector circuit may directly detect the position of the external control member using a lever or a push button, which moves along with the external control member. In accordance with the type of the external control member, the external control member circuit may be appropriately set up.
The power supply circuit for driving the logic circuit is not limited to the constant voltage regulator
161
, and any circuit capable of driving the logic circuit is acceptable.
In the first embodiment, the registers of pre_RYZ (for the previous crown position data) and now_RYZ (for the present crown position data) are arranged to determine whether there is any change in the crown position (step S
4
in FIG.
8
). Alternatively, only now_RYZ (for the present crown position data) may be arranged, and steps S
1
, S
3
, S
4
, and S
5
in
FIG. 8
may be eliminated to proceed from the detection of the crown position (S
2
) directly to the determination of the crown position (S
6
). In the first embodiment, a change in the crown position is determined, and only when there is any change, the power supply control process (S
7
through S
12
) is performed for efficient control.
The first embodiment of the present invention may be implemented in a self-winding generator timepiece, a solar-cell charging timepiece, or a battery driven timepiece, other than the electronically controlled mechanical timepiece. In these timepieces, the power consumption during the hand setting operation is reduced. The driving time is prolonged, while the indication error is eliminated because the oscillator circuit continuously works.
In the second and fifth embodiments, the indication error corrector unit
200
in the control circuit
56
detects the voltage applied to the capacitor
22
and the temperature thereof, and corrects the indication error by the correction value that accounts for the detected voltage and temperature. As in the third embodiment, the indication error may be corrected by a constant quantity correction corresponding to the predetermined value.
The correction of the indication error may be performed by only the voltage of the capacitor
22
, or in response to the rotation period of the generator
20
. For instance, the voltage of the capacitor
22
is detected to perform correction in accordance with the correction value responsive to the voltage value. When the voltage held by the capacitor
22
is as high as 1.2 V, the correction value may be “0”, and when the voltage held by the capacitor
22
is as low as 0.8 V, the correction value may be minus 1.0 second (−1.0 second).
The charge voltage to the capacitor
22
is typically proportional to the torque of the mainspring
1
a
applied to the generator
20
, and the torque determines the rotation speed of the hand. A check is made to determine the correspondence between the voltage value of the capacitor
22
and the fast/slow position of the hand at the start time at which the brake control starts with the oscillator circuit
51
driven by the voltage value of the capacitor
22
. The correspondence table between the voltage value and the hand indication error may be stored in the control circuit
56
or other circuit.
For instance, when the capacitor
22
is at 1.2 V, the hand position is free from a fast/slow error (no indication error) at the start time at which the brake control starts (approximately 0.2 second later). By setting the correction value to zero, the indication error is almost removed.
When the capacitor
22
is at 0.8 V, the hand has been driven (moved) by 9 seconds by the start of the brake control (the time to the oscillation, and approximately 8 seconds). By setting a correction of the difference of 1 second in the brake control, the indication error is almost removed.
The indication error corrector unit
200
is not limited to the arrangement in which the initial value is set in the up/down counter
54
in the second embodiment. For instance, the output value LBS of the up/down counter
54
may be directly adjusted for correction. Another brake circuit for correction, different from the normally used brake circuit
120
, may be arranged. It is important that the timepiece be constructed to correct the indication error thereof.
The specific construction of the switch
261
, namely, the power supply control unit, may be properly arranged. The power supply control unit is not limited to the mechanically driven switch, and may be an electrical switch. To reliably cut off the supply of power, the mechanically driven switch is preferable. Even when the electrical switch is employed, merely a leakage current (as large as approximately 1 nA) of a silicon diode forming the electrical switch is discharged, and the switch cutoff effect thereof is almost identical to that of the mechanically driven switch. The electrical switch practically presents no problems.
The switch
261
is not limited to the switch which is opened and closed in interlock with the operation of the crown (the time correction operation). Alternatively, the switch
261
may be a switch which is opened and closed in interlock with the stop and activation of the generator
20
or the train wheels. Interlocked with the operation of the crown, the switch
261
advantageously has a simple and low-cost construction.
In the second embodiment, the use of the second capacitor
25
is not a requirement. As shown in
FIG. 25
, the second capacitor
25
is dispensed with, and the capacitor
22
only may be used.
The charge control circuit
35
is not limited to the ones in the third and fourth embodiments. The charge control circuit
35
may be constructed of a one-way element and a resistor. A diode having no reverse leakage current may be used for the one-way element. In this case, the one-way element works like the diode
36
in the third embodiment, and the resistor works like the resistor
37
, and the advantages (3-1) through (3-9) of the third embodiment are equally enjoyed.
An active element, such as a comparator, may be used for the charge control circuit
35
. The charge control circuit
35
allows more charging current from the generator
20
to the main capacitor
31
, and less charging current to flow to the auxiliary capacitor
32
. When the voltage of the auxiliary capacitor
32
is higher than that of the main capacitor
31
, the auxiliary capacitor
32
supplies a current to the main capacitor
31
. To this end, the charge control circuit
35
is configured to adjust the charging current of the main storage unit and the auxiliary storage unit, and the direction and magnitude of the current flowing between the main storage unit and the auxiliary storage unit. The charge control circuit
35
constructed of passive elements only is preferable in view of a reduction in power consumption.
The control circuit
56
in the third and fourth embodiments corrects the indication error by the constant quantity correction corresponding to a predetermined constant value. Alternatively, as in the second embodiment, the indication error corrector unit
200
may be arranged to perform the correction in response to the voltage value, temperature, and the rotation period of the generator
20
. Furthermore, in the third and fourth embodiments, the use of the indication error corrector unit
200
is not a requirement. In this case, when temperature is extremely low, or when the voltage of the auxiliary capacitor
32
drops, the oscillator circuit
51
takes time to start oscillating, and an indication error is accordingly created. However, the indication error is removed in the course of the hand driving control. Specifically, with the indication error corrector unit
200
incorporated, the time required to remove the indication error is substantially shortened subsequent to the time correction operation. On the other hand, when the indication error corrector unit
200
is not arranged, the time required to remove the indication error is mildly prolonged. But this degree of time prolongation is not problematic in practice, because the indication error is removed within 1 to several minutes. When the voltage of the auxiliary capacitor
32
is assured with temperature not substantially low, the time the oscillator circuit takes to start oscillating is typically short, and the indication error is removed without the need for the indication error corrector unit
200
.
The specific construction of the switch
361
may be appropriately set up. The switch
361
is not limited to the one which is opened and closed in interlock with the operation of the crown. The switch
361
may be opened and closed in interlock with the stop and activation of the generator
20
or the train wheels. However, if the switch
361
is interlocked with the operation of the crown, it will be manufactured simply and for a low cost.
The types, the reverse leakage currents, and the resistances of the diodes
36
and
38
, and the resistor
37
may be appropriately determined in design. Particular attention needs to be given to the resistance of the resistor
37
and the reverse leakage current of the diode
38
, because these affect the magnitude of the charging current of the auxiliary capacitor
32
.
In the first embodiment, the indication error corrector unit
200
may be included in the control circuit
56
as in the second embodiment. The power supply circuit
30
in the third and fourth embodiments may be arranged as a power supply circuit in the first embodiment. In the first embodiment, even when the generator
20
stops during the time correction operation, the oscillator circuit
51
continuously remains operative from power from the capacitor
22
. The timepiece of the first embodiment is free from the indication error at the shifting back from the time correction operation. However, an indication error takes place when the capacitor
22
is discharged to the extent that the oscillator circuit
51
becomes inoperative if a time correction operation takes time or if the timepiece has been left unattended for a long period of time. With the power supply circuit
30
incorporated, the oscillator circuit
51
quickly restarts, reducing the indication error at the moment the generator
20
becomes operative, even when the capacitor
22
is discharged. With the indication error corrector unit
200
further incorporated, the indication error at the restart of the oscillator circuit
51
is even more reduced.
In each of the above embodiments, two types of chopping signals CH
3
having different duty factors are input to the switch
121
for brake control. The brake control may be performed by inputting an inverted LBS signal, rather than using the chopping signal. In each of the above embodiments, the brake control is performed by making a closed loop between the terminals MG
1
and MG
2
in the generator
20
to carry out a short-circuit brake. Alternatively, the brake control may be performed by connecting a variable resistor to the generator
20
to vary a current flowing through the coil of the generator
20
. Consequently, the specific construction of the brake control circuit
56
is not limited to the arrangement shown in
FIG. 2
, and may be appropriately set up.
The mechanical energy source for driving the generator
20
is not limited to the mainspring
1
a
, and may be a rubber member, a spring, a weight, or a fluid such as compressed air. An appropriate mechanical energy source may be selected in accordance with an apparatus in which the present invention is implemented. Means for feeding mechanical energy to the mechanical energy source may be manual winding, an oscillating weight, potential energy, pressure variations, wind force, wave power, hydraulic power, or temperature differences.
Mechanical energy transmission means for transmitting mechanical energy from the mechanical energy source such as a mainspring to the generator is not limited to the train wheels
7
(gears), and may be a frictional wheel, a belt (such as a timing belt), a pulley, a chain, a sprocket wheel, a rack and pinion, or a cam. The mechanical energy transmission means is appropriately set up in accordance with the type of the electronically controlled timepiece in which the present invention is implemented.
The generator is not limited to the one which generates power through electromagnetic conversion by rotating the rotor. Alternatively, the generator may be a generator of a different type, such as a piezoelectric generator which adds pressure to a piezoelectric element.
The time display unit is not limited to the hand
13
, and may be a disk, a ring-shaped member or a sector member. The time display unit may be a digital display unit employing a liquid-crystal display panel.
Industrial Applicability
As discussed above, the time indication error is reduced in the electronically controlled timepiece of the present invention, the power supply control method for the electronically controlled timepiece, and the time correction method for the electronically controlled timepiece.
In the electronically controlled timepiece and the power supply control method therefor in accordance with a first invention, the use of the power source switch and the clock input limiting means reduces the power consumption involved in the time correction operation, (the hand setting operation). Since the oscillator circuit continuously remains operative during the time correction operation, a time indication error at the time of shifting back from the time correction operation is eliminated.
In the electronically controlled timepiece and the time correction method therefor in accordance with a second invention, increasing the capacitance of the capacitor and the size of the mechanical energy source is not required. The electronically controlled timepiece is thus miniaturized with costs thereof reduced. Even when the time correction operation (the hand setting operation) takes time, the time the oscillator circuit takes to start oscillating is shortened. Since the indication error corrector unit corrects the indication error, the indication error of the hand subsequent to the time correction operation is minimized.
In the electronically controlled timepiece and the power supply control method therefor in accordance with a third invention, the rotation controller is quickly driven to reduce an error in the time control when the generator starts generating. Furthermore, the passive elements, such as a diode and a resistor, are used for the charge control circuit, the power consumption involved therein and the power generating capacity may be small, compared with the arrangement in which an active element, such as a comparator, is employed.
Claims
- 1. An electronically controlled timepiece comprising:a power source; a logic circuit; an analog circuit driven by said power source, said analog circuit including a power supply circuit arranged in the analog circuit and having an output for driving said logic circuit; an oscillator circuit driven by the output of said power supply circuit for the logic circuit; a power source switch for suspending the supply of electrical energy from said power source to said analog circuit except said power supply circuit for said logic circuit during a time correction operation of the electronically controlled timepiece; and clock input limiter for suspending a clock input from said oscillator circuit to said logic circuit during said time correction operation.
- 2. An electronically controlled timepiece according to claim 1, wherein the power supply circuit for the logic circuit comprises a constant voltage regulator.
- 3. An electronically controlled timepiece according to of claim 1, comprising logic circuit initializing means for initializing the internal status of the logic circuit during the time correction operation.
- 4. An electronically controlled timepiece according to claim 1, comprising:a mechanical energy source, a generator which is driven by the mechanical energy source, and generates an electromotive force, thereby supplying electrical energy, and a rotation controller, driven by the electrical energy, for controlling the rotation period of the generator.
- 5. A power supply control method for an electronically controlled timepiece comprising a power source, an analog circuit driven by the power source, said analog circuit including a power supply circuit arranged in the analog circuit for a logic circuit, the logic circuit being driven by the output of the power supply circuit therefor, and an oscillator circuit driven by the output of the power supply circuit for the logic circuit, the power supply control method comprising:the step of suspending the supply of electrical energy from the power source to the analog circuit except the power supply circuit for the logic circuit during a time correction operation of the electronically controlled timepiece, and the step of suspending a clock input from the oscillator circuit to the logic circuit during the time correction operation.
- 6. A power supply control method for an electronically controlled timepiece according to claim 5, comprising the step of initializing the internal status of the logic circuit during the time correction operation of the electronically controlled timepiece.
- 7. An electronically controlled timepiece comprising:a mechanical energy source; a generator driven by the mechanical energy source, said generator being effective for outputting electrical energy; a storage unit for storing electrical energy output by the generator; a rotation controller driven by electrical energy supplied by the storage unit, said rotation controller being effective for controlling the rotation period of the generator; a power supply control unit for suspending the supply of electrical energy from the storage unit to the rotation controller while the generator stops the operation thereof in response to a time correction operation, and an indication error corrector unit for correcting an error in time indication until the rotation controller resumes a normal operation wherein the power supply control unit restarts the supply of electrical energy from the storage unit to the rotation controller in response to the activation of the generator.
- 8. An electronically controlled timepiece according to claim 7, wherein the indication error corrector unit is designed to perform a constant quantity correction corresponding to a predetermined value.
- 9. An electronically controlled timepiece according to claim 7, wherein the indication error corrector unit sets a correction value in accordance with a voltage of the storage unit.
- 10. An electronically controlled timepiece according to claims 7, wherein the indication error corrector unit adjusts a correction value in response to detected temperature.
- 11. An electronically controlled timepiece according to claim 7, wherein the indication error corrector unit comprises:a temperature sensor, a voltage detector for measuring a voltage of the storage unit, and a correction value setter for setting a correction value based on values detected by the temperature sensor and the voltage detector.
- 12. An electronically controlled timepiece according to one of claim 7, wherein the power supply control unit comprises a switch which is connected in series with the storage unit and is closed while the generator is running, and is opened while the generator is not running.
- 13. An electronically controlled timepiece according to claim 12, wherein the switch is a mechanically driven switch.
- 14. An electronically controlled timepiece according to claim 13, wherein the switch is a mechanically driven switch that is opened when a crown remains pulled out during a time correction mode, and is closed when the crown is pushed in during a normal mode.
- 15. An electronically controlled timepiece according to claim 7, comprising a second storage unit connected in parallel with the storage unit.
- 16. A time correction method for an electronically controlled timepiece including a mechanical energy source, a generator driven by the mechanical energy source, said generator being effective for outputting electrical energy, a storage unit for storing electrical energy output by the generator, and a rotation controller driven by electrical energy supplied by the storage unit, said rotation controller being effective for controlling the rotation period of the generator, said time correction method comprising:the step of suspending the supply of electrical energy from the storage unit to the rotation controller during a time correction operation of the electronically controlled timepiece, and the step of correcting an error in time indication until the rotation controller resumes a normal operation when the supply of electrical energy from the storage unit to the rotation controller is restarted at the end of the time correction operation.
- 17. A time correction method for an electronically controlled timepiece according to claim 16, wherein an indication error is corrected by a constant quantity correction corresponding to a predetermined value at the end of the time correction operation.
- 18. A time correction method for an electronically controlled timepiece according to claim 16, wherein an indication error is corrected by a correction value set in response to a voltage of the storage unit, at the end of the time correction operation.
- 19. A time correction method for an electronically controlled timepiece according to one of claim 16,wherein temperature is detected at the end of the time correction operation, and the correction value is adjusted in response to the detected temperature.
- 20. A timepiece comprising:a power supply including: a first power rail and a second power rail; a power generator selectively placed in an active mode in which power is supplied to said first and second power rails and in an inactive mode in which power is not supplied to said first and second power rails; a first power storage device for receiving power from said power generator through said first and second power rails; a first power load coupled to said first power storage device; a second power load coupled to said first power storage device, said second power load being a voltage regulator having an output coupled to a third power rail to provide a regulated output voltage on said third power rail; a pulse generator coupled to said third power rail for receiving said regulated output voltage, said pulse generator having a clock output for producing a clocking signal when the voltage of said third power rail is above a minimum active voltage level; a digital circuit coupled to said third power rail for receiving said regulated output voltage and having a clock input selectively coupled to said clock output; wherein said first power load is decoupled from said first power storage device and said clock input is decoupled from said clock output when said power generator is in said inactive mode.
- 21. The timepiece of claim 20 wherein said first power load is an analog circuit.
- 22. The timepiece of claim 20 wherein said pulse generator and said digital circuit are maintained coupled to said third power rail during both active and inactive modes of said power generator.
- 23. The timepiece of claim 20 wherein said pulse generator includes at least an oscillator.
- 24. The timepiece of claim 23, wherein said oscillator is substantially the only load on said third power rail drawing power from said third power rail during said inactive mode.
- 25. The timepiece of claim 20 further having a logic gate to mask the output of said clock output from said clock input during said inactive mode whereby said clock input is decoupled from said clock output.
- 26. The timepiece of claim 20, wherein said digital circuit includes a control output node for producing a periodic error correction signal for regulating the generation of power by said power generator when said power generator is in said active mode and for producing no error correction signal when said power generator is said inactive mode.
- 27. The timepiece of claim 26, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is larger when the voltage of said third power rail falls below said minimum active voltage level during said inactive mode than when the voltage of said third power rail remains above said minimum active voltage level during said inactive mode.
- 28. The timepiece of claim 26, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is dependent on the voltage of said first power storage device.
- 29. The timepiece of claim 28, wherein the initial amount of power regulation is inversely proportional to the voltage of said first power storage device.
- 30. The timepiece of claim 28, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is further dependent on temperature.
- 31. The timepiece of claim 30, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is inversely proportional to temperature.
- 32. The timepiece of claim 30, wherein said digital circuit further includes:a temperature sensor to produce a digital representation of the temperature; a voltage detector coupled to said first power storage device to produce a digital representation of observed voltage across said first power storage device.
- 33. The timepiece of claim 26, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is dependent on initial conditions of said digital circuit following a transition from said inactive mode to said active mode of said power generator.
- 34. The timepiece of claim 33, wherein said initial conditions are loaded as a numerical value into said digital circuit following said inactive mode.
- 35. The timepiece of claim 34, wherein said numerical value is fixed such that said digital circuit has the same initial conditions at every transition from said inactive mode to said active mode.
- 36. The timepiece of claim 34, wherein the numerical value loaded into said digital circuit is a first predetermined value when the voltage of said third power rail remains above said minimum active voltage value during said inactive mode and is a second predetermined value when the voltage of said third power rail falls below said minimum active voltage value during said inactive mode.
- 37. The timepiece of claim 36, wherein said second predetermined value is greater than said first predetermined value.
- 38. The timepiece of claim 34, wherein the numerical value loaded into said digital circuit is selected from a table of predetermined values.
- 39. The timepiece of claim 38, wherein the numerical value to be loaded into said digital circuit is selected from among said predetermined values in said table in accordance with a measured voltage across said first power storage device and a measured temperature.
- 40. The timepiece of claim 39, wherein said digital circuit further includes:a temperature sensor to measure said temperature and produce a digital representation of the measured temperature; a voltage detector coupled to said first power storage device to produce a digital representation of said measured voltage across said first power storage device.
- 41. The timepiece of claim 20, wherein the duty cycle of said error correction signal is dependent on initial conditions of said digital circuit following a transition from said inactive mode to said active mode of said power generator.
- 42. The timepiece of claim 26, wherein the initial duty cycle of said error correction signal at a transition from said inactive mode to said active mode is larger when the voltage of said third power rail falls below said minimum active voltage level during said inactive mode than when the voltage of said third power rail remains above said minimum active voltage level during said inactive mode.
- 43. The timepiece of claim 26, wherein at a transition from said inactive mode to said active mode, the initial duty cycle of said error correction signal is assigned a first predetermined value if the voltage of said third power rail falls below said minimum active voltage level during said inactive mode and assigned a second predetermined value otherwise.
- 44. The timepiece of claim 26, wherein at a transition from said inactive mode to said active mode, the initial duty cycle of said error correction signal is determined by an assigned value dependent on the voltage of said first power storage device.
- 45. The timepiece of claim 44, wherein said assigned value is further dependent on temperature.
- 46. The timepiece of claim 26, wherein said error correction signal is effective for regulating the generation of power by said power generator when said power generator is in said active mode.
- 47. The timepiece of claim 26, wherein said control output node is coupled to a control input node of said power generator and is effective for retarding the generation of power by said generator in accordance with said error correction signal.
- 48. The timepiece of claim 26, wherein said power generator includes an AC power generating circuit coupled to a voltage rectifier, and said digital circuit includes at least an error correction circuit for generating said error correction signal, said error correction circuit being responsive to the frequency of said AC power generating circuit.
- 49. The timepiece of claim 48, wherein said power generator uses a multiple of said clocking signal to obtain a measure of the frequency of said AC power generating circuit, the duty cycle of said error correction signal being adjusted to be proportional to said measure of the frequency of said AC power generating circuit.
- 50. The timepiece of claim 49, wherein said error correction signal is effective for reducing the frequency of said AC power generating circuit whereby a feedback system is established.
- 51. The timepiece of claim 50, wherein said error correction circuit includes a counter for determining the application of said error correction signal, said counter being reset to an initial count value at a transition from said inactive mode to said active mode.
- 52. The timepiece of claim 51, wherein said counter is reset to the same predetermined count value at every transition from said inactive mode to said active mode.
- 53. The timepiece of claim 51, wherein said counter is reset to a first predetermined count value in response to the voltage of said third power rail remaining above said minimum active voltage during said inactive mode, and is reset to a second predetermined count value in response to the voltage of said third power rail falling below said minimum active voltage during said inactive mode.
- 54. The timepiece of claim 53, wherein said second predetermined count value is greater than said first predetermined count value.
- 55. The timepiece of claim 53, wherein said second predetermined count value is selected from a table of available count values.
- 56. The timepiece of claim 55, wherein a target count value from among said table of available count values is selected as said second predetermined count value in accordance with the voltage across said first power storage device.
- 57. The timepiece of claim 55, wherein a target count value from among said table of available count values is selected as said second predetermined count value in accordance with the temperature of said pulse generator.
- 58. The timepiece of claim 20, further having a second power storage device coupled between said first and second power rails, said first power storage device being decoupled from at least one of said first and second power rails during said inactive mode and being re-coupled to said first and second power rails in response to said active mode.
- 59. The timepiece of claim 58, wherein said second power storage device remains coupled to said first and second power rails during both of said active mode and inactive mode.
- 60. The timepiece of claim 58, wherein said first power storage device has a greater power storage capacity than said second power storage device.
- 61. The timepiece of claim 60, wherein said first and second power storage devices are respective first and second capacitors.
Priority Claims (3)
Number |
Date |
Country |
Kind |
10-268529 |
Sep 1998 |
JP |
|
11-060463 |
Mar 1999 |
JP |
|
11-226534 |
Aug 1999 |
JP |
|
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/JP99/05171 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO00/17716 |
3/30/2000 |
WO |
A |
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4295215 |
Kitai et al. |
Oct 1981 |
A |
Foreign Referenced Citations (4)
Number |
Date |
Country |
5-79493 |
Oct 1993 |
JP |
8-5758 |
Jan 1996 |
JP |
8-75874 |
Mar 1996 |
JP |
10-300862 |
Nov 1998 |
JP |