Patent Application
20190372374
Embodiments described herein relate generally to a power reception device having a contactless charging function and a charging control program of such a power reception device.
Recently, there is a technology to charge a power reception device such as a smart phone or a portable printer in a non-contact manner without connecting the power reception device with a power supply device through a cable. In other words, a user can charge the power reception device only by placing the power reception device on the power supply device. On the other hand, in order to efficiently perform non-contact charging, the user needs to place a power transmission coil in the power supply device and a power reception coil in the power reception device so that positions thereof match each other. Therefore, preferably, the user can determine whether or not the power reception device is placed at a correct position on the power supply device.
An object of an exemplary embodiment is to provide a power reception device which can notify a user that the power reception device is not placed at a correct position on a power supply device.
In general, according to one embodiment, there is provided a power reception device including a power reception coil, a power reception unit, a notification unit, and a control unit.
The power reception coil receives power from the power supply device in a non-contact manner. The power reception unit causes the received power as a charging current to flow to a load. The notification unit notifies that a relative position of the power reception device to the power supply device is inappropriate. The control unit starts charging by a charging current which is set to a first current value and controls the charging current so as to gradually increase the charging current. When the charging is stopped before the charging current reaches a second current value larger than the first current value, notification is performed that the relative position of the power reception device to the power supply device is inappropriate based on the current value of the charging current when the charging is stopped.
Hereinafter, embodiments will be described with reference to the drawings.
The power supply device 100 is configured of a flat plate-shaped casing on which the printer 200 is placed, and includes a power transmission coil 105 above an inside portion of the casing (on side close to printer 200). The power supply device 100 includes an LED or the like which displays a power transmission state. In addition, the power supply device 100 includes a configuration that includes a power transmission coil 105 and transmits power in a non-contact manner.
The printer 200 can be charged in a non-contact manner by being placed on the power supply device 100. In the printer 200, the power reception coil 205 is placed below the inside portion of the casing (on side close to power supply device 100) so as to face the power transmission coil 105. The printer 200 includes an openable and closable cover 245 that loads and unloads other printing paper, a display unit 230, a secondary battery 240 as a load, and the power reception coil 205, and has a configuration that receives power in a non-contact manner, and the like. A configuration relating to power transmission and charging in a non-contact manner will be described in detail with reference to
As illustrated in
The power supply device 100 includes a power source unit 110, a power transmission unit 115, a communication unit 120, a display unit 125, and a control unit 130.
The power source unit 110 is supplied with power from an AC adaptor or the like provided outside or inside the power supply device 100 and supplies power appropriate for each unit in the power supply device 100.
The power transmission unit 115 includes an oscillation unit that generates a high-frequency signal and a power amplification unit that amplifies the generated high-frequency signal. A DC voltage supplied from the power source unit 110 is converted into an AC voltage, generates high-frequency power, and transmits power from the power transmission coil 105.
The communication unit 120 includes an interface that performs a communication with a communication unit 225 (to be described below) of the printer 200 by a wireless communication unit by electric waves or infrared rays or the like, or a communication unit that performs load modulation of a carrier wave used for power transmission, or the like. By communicating with the communication unit 225, the communication unit 120 receives information of a power value received by the printer 200 and transmits the information to the control unit 130 to be described below.
In addition to a liquid crystal display device, the display unit 125 may be an input and output device such as a touch panel.
The control unit 130 includes a CPU as a computation device and a memory as a storage device. The control unit 130 controls power to be transmitted from the power transmission unit 115 based on a request sent from the printer 200 via the communication unit 120. A threshold value Th for limiting the current flowing from the power transmission unit 115 to the power transmission coil 105 is stored in the memory and if the current value exceeds the threshold value Th, the control unit 130 controls the power transmission so as to stop the power transmission by the power transmission unit 115. The threshold value Th is set based on the maximum value of the power that can be transmitted by the power supply device 100.
The printer 200 includes a power reception coil 205, a power reception unit 210, a charging unit 215, a control unit 220, a communication unit 225, a display unit 230, a printing unit 235, and a secondary battery 240 as a load.
The power reception coil 205 receives power by a magnetic field coupling such as electromagnetic induction with the power transmission coil 105.
The power reception unit 210 includes a rectifying unit that rectifies AC power received by the power reception coil 205 into DC power and a DC/DC unit that converts a voltage. The power reception unit 210 converts the DC voltage generated by the rectifying unit into a DC voltage appropriate for an operation of the charging unit 215 to be described below and supplies the DC voltage to the charging unit 215.
The charging unit 215 generates a voltage and a current appropriate for charging the load (secondary battery) 240 and charges the secondary battery 240. Hereinafter, the current supplied from the charging unit 215 to the secondary battery 240 is set as a charging current.
The control unit 220 includes a CPU as a computation device and a memory as a storage device. In addition, the control unit 220 measures a voltage output from the power reception unit 210, and requests the power supply device 100 to adjust the transmitted power via the communication unit 225 so that a voltage value required by the charging unit 215 can be obtained. In addition, the control unit 220 sets a current value of the charging current with respect to the charging unit 215 so that an actual current value of the received current can be detected. Therefore, if there is a difference between the set current value of the charging current and the actual current value of the charging current, adjustment of the transmitted power can be requested to the power supply device 100 via the communication unit 225. In addition, when the control unit 220 detects that the charging current is zero despite of setting the charging current so as to charge the secondary battery 240 with a predetermined current value, the control unit determines that power transmission is stopped by the power supply device 100.
The communication unit 225 includes an interface that performs a communication with the communication unit 120 of the power supply device 100 by a wireless communication unit by electric waves or infrared rays, or a communication unit that performs load modulation of a carrier wave used for power transmission, or the like.
The display unit 230 displays a state of a position of the power reception device or the like. In addition to a liquid crystal display device, the display unit 230 may be an input and output device such as a touch panel. In the embodiment, the display unit 230 corresponds to the notification unit.
The printing unit 235 includes a thermal head and a platen roller. For example, the thermal head performs printing by heating a heat sensitive type sheet based on a print command from a host computer. The platen roller is rotationally driven by the control unit 220 in synchronization with a printing operation.
Here, if the charging continues in a state where the charging efficiency is low, since the power loss increases, not only the heat generation of the power supply device 100 increases but also the power supply device 100 may stop power transmission. Specifically, since the position of the printer 200 is poor and the charging efficiency decreases, there is a case where the printer 200 cannot receive the minimum power necessary for charging. At this time, although the printer 200 repeatedly requests the power supply device 100 to increase the power transmission amount, as a result, if the power transmission amount exceeds the maximum power that can be transmitted by the power supply device 100, the power supply device 100 stops power transmission. Specifically, if the current value of the current flowing from the power transmission unit 115 to the power transmission coil 105 exceeds the threshold value Th, the power supply device 100 controls the power transmission so as to stop power transmission by the power transmission unit 115.
Once the power supply device 100 stops power transmission, for example, the power supply device 100 stops transmitting power until the position of the printer 200 is changed. Therefore, in this case, the user needs to receive a notification that the printer 200 is not placed at a correct position on the power supply device 100.
With respect to such a problem, in the printer 200 of the embodiment, the control unit 220 sets a charging current to start the charging from a small current value and thereafter gradually increase the current value. Accordingly, the charging efficiency and the position where the printer 200 is placed are estimated based on the charging current which is set when power transmission from the power supply device 100 is stopped.
Here, if the transmission power of the power supply device 100 is set to P1 and the power received by the printer 200 is set to P2, the efficiency E (%) of non-contact charging is given by the following equation.
E=(P2/P1)×100 (1)
Further, if the charging voltage of the printer 200 is V2 and the power consumed by the printer 200 such as the control unit 220 other than the power charging the secondary battery 240 is P3, the charging current I can be expressed as follows.
(P2−P3)/V2=I (2)
By equations (1) and (2),
E=((V2×I+P3)/P1)×100 (3)
Since the charging voltage V2, the power P3 other than the charging, and the transmitted power P1 are known values in advance, if the charging current I is detected when the power transmission is stopped, the control unit 220 can calculate the charging efficiency E and can estimate a position where the printer 200 is placed at the same time.
Next, control of the control unit 220 will be specifically described as an example of the following conditions.
Transmission power P1: 7W (maximum)
Charging voltage V2: 4.2V (maximum)
Power consumption P3 of the control unit 220 or the like: 0.5W
In the example described above, if a load is applied to the power supply device 100 such that the power transmission output exceeds 7W, the power supply device 100 stops power transmission. In addition, the charging voltage is the maximum value if the secondary battery 240 as a load is a lithium ion battery of one cell. In addition, the power consumption P3 of the control unit 220 or the like indicates power consumed by the printer 200 such as the control unit 220 other than the power charging the secondary battery 240. In addition, the charging current value appropriate for charging is set to 1.0A.
Under such a condition, the control unit 220 starts charging. If the charging is stopped when the charging current is 0.2A (
In this manner, the control unit 220 determines the region where the printer 200 is placed based on the current value of the charging current when the charging is stopped. Based on the region where the printer 200 is placed, the control unit 220 displays on the display unit 230 that the position is inappropriate and the charging cannot be performed, the printer 200 is placed at a proper position, or the like, and thus notifies the user of a position state thereof.
As an example, although the charging voltage V2 of the printer 200 is treated as 4.2V, 4.2V is a value in a state where the secondary battery 240 is close to full charge. Therefore, the charging voltage V2 may be calculated as 3.5V or 4.0V, for example, depending on the battery capacity.
In the example, although the control unit 220 calculates the charging efficiency based on the current value of the charging current when the charging is stopped, the control unit 220 may calculate the current value between the charging current values before the charging current increases or before the charging current increases and when the charging is stopped.
Contents to be displayed are not limited to the contents described above, and for example, the charging efficiency or the estimated position may be displayed as a numerical value. In addition, in the embodiment, although the display unit of the power reception device is described as an example of the notification unit, the display unit is not limited to this. For example, the notification unit can also adopt a form that notifies whether or not the position of the printer 200 is at a proper position or how far the position is shifted by sound.
These notifications are not limited to those by the notification unit provided in the printer. For example, by communication with an external device such as a smart phone, the printer 200 may notify by the notification unit of the external device.
For example, if the printer 200 is placed on the power supply device 100, the control unit 220 starts charging control by the set current value of the charging current (Act 100). The current value of the charging current when the charging is started is stored in the memory, which is 0.2A in the example of
Next, the control unit 220 displays on the display unit 230 that the position of the printer 200 is shifted from the calculated result (Act 107). At this time, the control unit 220 may change the display content according to the shift amount of the printer 200.
Thereafter, since the printer 200 cannot be charged until the printer is placed at an appropriate position by the user, the control unit 220 ends the charging (Act 105, Yes), and ends a series of control.
On the other hand, if power transmission of the power supply device 100 continues in the Act 101 (Act 101, Yes), the control unit 220 changes control according to whether or not the current value of the charging current reaches the preset target value in the control unit 220. In the example of
If the current value of the charging current does not reach the target value, the control unit 220 increases the charging current by a predetermined amount (Act 103). In the example of
If the current value of the charging current reaches the target value (Act 102, Yes), the control unit 220 continues the charging as it is (Act 104). The charging continues until the secondary battery 240 is fully charged. If the secondary battery 240 is fully charged, the control unit 220 ends the charging (Act 105, Yes) and ends a series of control.
When control of charging described above is started, the printer 200 may perform authentication processing by communication with the power supply device 100. If the authentication processing is performed, the power supply device 100 starts power transmission to the printer 200 after the authentication is completed.
As described above, the printer of the first embodiment determines that the printer is not placed at a proper position on the power supply device, based on the charging current which is set when the charging is stopped. With such a configuration, the user can receive a notification that the printer is not placed at a correct position on the power supply device only with the printer without mounting a special function on the power supply device.
With reference to
The control unit 220 determines a state of the position of the printer 200 based on the current value of the charging current when the charging is stopped and the user receives a notification of the state by the display unit 230. As a result, if the printer 200 is repositioned by the user, the power reception is started again. At this time, the charging is started again from the current value of the charging current when the charging is stopped (
The subsequent processing is the same as that in the first embodiment. In addition, if the power transmission for the power supply device 100 is stopped again after the charging resumes (
In the second embodiment, when the charging is resumed after the charging is stopped, the control unit 220 resumes the charging from the current value of the charging current when the power transmission is stopped. Since the printer can be expected to be repositioned at the further center position thereof when the user repositions the printer 200, the current value of the charging current is not required to set to the current value of the charging current which is set immediately before the power transmission is stopped for charging. By controlling the control unit as described above, determination with respect to whether or not the center of the power reception coil 205 is placed at a proper position can be performed in a short time.
As described above, the printer according to each of the embodiments can determine that the printer is not placed at a proper position on the power supply device based on the charging current that is set when power transmission from the power supply device is stopped.
The power reception unit and the charging unit in these embodiments are not clearly distinguished from each other and maybe treated as a power reception unit which is a combination of the power reception unit and the charging unit with each other.
In the examples of these embodiments, although the region where the printer is placed is calculated from the current value of the charging current at the time of the charging being stopped, these relationships may be prepared in advance as a table and be stored in the memory of the printer in a callable state.
The power reception device is not limited to a portable printer but may be a mobile device such as a smart phone. Like the portable printer, the smart phone is also provided with a display unit and a load.
The values of the current value and the efficiency of the charging current described in these embodiments are merely examples and are not limited to the above values. In addition, although a secondary battery is exemplified as a load, the load is not limited to a secondary battery, and the load may be a circuit constituting a power reception device, for example.
In the above examples, although the charging current after the charging is started increases step by step, as an example, the charging current is not limited to this example. For example,
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-196991 | Oct 2016 | JP | national |
This application is a Divisional of application Ser. No. 16/195,919 filed on Nov. 20, 2018, which is a Continuation of application Ser. No. 15/725,464 filed on Oct. 5, 2017, the entire contents of both of which are incorporated herein by reference. This application is based upon and claims the benefit of priority from Japanese Patent Application No. P2016-196991, filed Oct. 5, 2016, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16195919 | Nov 2018 | US |
| Child | 16543700 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15725464 | Oct 2017 | US |
| Child | 16195919 | US |
