This application claims the priority benefit of Taiwan application serial no. 100100173, filed on Jan. 4, 2011. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
1. Field of the Invention
The invention relates to a driving technique for a fluorescent tube, more particularly, to a driving apparatus for a hot-cathode fluorescent tube, a method thereof and an illumination apparatus using the same.
2. Description of Related Art
Fluorescent tubes are generally used as illumination apparatus in daily life, wherein straight long tube type (hot-cathode) fluorescent tubes are most commonly used, and the fluorescent tubes have different tube diameters of T3, T5, T8 and T9 in specification. However, regardless of the fluorescent tube of the T3, T5, T8 or T9 specification, a light emitting principle thereof is the same, by which a tube current induces a mercury vapor to stimulate a fluorescent material on an inner wall of the tube to emit light.
Driving apparatuses of the existing fluorescent tubes (T9/T8/T5/T3) are generally divided into two types, and one type provides none protection mechanism/measure when the fluorescent tube is broken, and another type may provide a shutdown protection mechanism/measure when the fluorescent tube is broken. In detail, when the fluorescent tube installed on a lamp holder is broken, and when the driving apparatus of the fluorescent tube does not provide any protection mechanism/measure, the driving apparatus of the fluorescent tube continuously supplies power to both ends of the broken fluorescent tube. However, a person replacing the fluorescent tube is not necessarily a professional personnel, who may probably replace the fluorescent tube without first turning off a power switch related to the fluorescent tube. Therefore, during a fluorescent tube replacing process, the tube-replacing personnel may have a security problem of electric shock.
On the other hand, when the fluorescent tube installed on the lamp holder is broken, and when the driving apparatus of the fluorescent tube can provide the protection mechanism/measure, the driving apparatus of the fluorescent tube stops supplying power to both ends of the broken fluorescent tube, so that the tube-replacing personnel does not have the security problem of electric shock. However, the lamp holder of the fluorescent lamp is generally installed on the ceiling, and the power switch related to the fluorescent tube is generally installed on a wall, so that when the fluorescent tube is broken and is required to be replaced, since a height of the ceiling is relatively high, the tube-replacing personnel has to replace the broken fluorescent tube with assistance of a ladder.
However, in order to confirm whether the newly installed fluorescent tube is properly installed or whether the newly installed fluorescent tube is usable, the tube-replacing personnel has to first climb down the ladder to switch (i.e. to turn on or turn off) the power switch installed on the wall, so as to determine whether the newly installed fluorescent tube normally emits light. If the newly installed fluorescent tube cannot emit light, it represents that the newly installed fluorescent tube is probably not installed well or is not good, and the tube-replacing personnel has to re-climb up the ladder to fix the fluorescent tube or again replace the broken fluorescent tube, and then climbs down the ladder to switch the power switch installed on the wall to further confirm whether the newly installed fluorescent tube normally emits light.
Therefore, the tube-replacing personnel probably need to repeatedly climb up and down the ladder to successfully replace the fluorescent tube. In this way, not only more time and labor are consumed, there is a potential risk of falling down.
Accordingly, the invention is directed to a driving apparatus of a fluorescent tube and a method thereof and an illumination apparatus using the same, which can provide a power-off protection mechanism/measure when the fluorescent tube is broken. Meanwhile, after the fluorescent tube is replaced, the newly installed fluorescent tube can be automatically detected and automatically lighted up.
The invention provides a driving apparatus of a fluorescent tube, which includes a conversion unit, a power factor correction unit, a driving unit and a detection unit. The conversion unit receives an alternating current (AC) power, and converts the AC power to provide a direct current (DC) power. The power factor correction unit is coupled to the conversion unit for performing a power factor correction to the DC power provided by the conversion unit. The driving unit is coupled to the power factor correction unit for generating an AC driving signal in response to an output of the power factor correction unit, so as to drive a first fluorescent tube installed on a lamp holder.
The detection unit is coupled to the driving unit for detecting whether a high side filament and a low side filament of the first fluorescent tube are broken, wherein when at least one of the high side filament and the low side filament of the first fluorescent tube is broken, the detection unit makes the driving unit to stop generating the AC driving signal, and when the broken first fluorescent tube originally installed on the lamp holder is replaced by a good second fluorescent tube, the detection unit makes the driving unit to regenerate the AC driving signal to drive the second fluorescent tube.
In an embodiment of the invention, the detection unit includes a high voltage detection circuit. The high voltage detection circuit is coupled to the high side filament of the first fluorescent tube for detecting whether the high side filament of the first fluorescent tube is broken, and sending a first detecting signal having a first state to the driving unit when the high side filament of the first fluorescent tube is broken, so as to make the driving unit to stop generating the AC driving signal, and sending the first detecting signal having a second state to the driving unit when the broken first fluorescent tube originally installed on the lamp holder is replaced by the good second fluorescent tube, so as to make the driving unit to regenerate the AC driving signal.
In an embodiment of the invention, the detection unit further includes a low voltage detection circuit. The low voltage detection circuit is coupled to the low side filament of the first fluorescent tube for detecting whether the low side filament of the first fluorescent tube is broken, and sending a second detecting signal having a first state to the driving unit when the low side filament of the first fluorescent tube is broken, so as to make the driving unit to stop generating the AC driving signal, and sending the second detecting signal having a second state to the driving unit when the broken first fluorescent tube originally installed on the lamp holder is replaced by the good second fluorescent tube, so as to make the driving unit to regenerate the AC driving signal.
In an embodiment of the invention, each of the first and the second fluorescent tube is at least a T3, T5, T8 or T9 hot-cathode fluorescent tube.
The invention provides a method for driving a fluorescent tube, which includes following steps. An alternating current (AC) power is converted into a direct current (DC) power. A power factor correction is performed on the DC power. An AC driving signal is generated in response to the power-factor corrected DC power, so as to drive a first fluorescent tube installed on a lamp holder to emit light. It is detected whether a high side filament and a low side filament of the first fluorescent tube are broken. When at least one of the high side filament and the low side filament of the first fluorescent tube is broken, it is stopped generating the AC driving signal, and when the broken first fluorescent tube originally installed on the lamp holder is replaced by a good second fluorescent tube, the AC driving signal is regenerated to drive the second fluorescent tube.
In an embodiment of the invention, the driving method further includes continuously using the AC driving signal to drive the first fluorescent tube when none of the high side filament and the low side filament of the first fluorescent tube is broken.
In an embodiment of the invention, the driving method further includes continuously stopping generating the AC driving signal when the broken first fluorescent tube is still installed on the lamp holder.
The invention provides an illumination apparatus including a lamp holder installed with a fluorescent tube, a power switch and the aforementioned driving apparatus of the fluorescent tube.
According to the above descriptions, when the fluorescent tube is broken, the driving apparatus stops providing power to both ends of the broken fluorescent tube regardless of whether a power switch related to the fluorescent tube is in an ON state or an OFF state, and thus making sure that a tube-replacing personnel is under safety conditions without getting an electric shock during a process of replacing the broken fluorescent tube with a good fluorescent tube. Meanwhile, after the broken fluorescent tube is replaced, it is unnecessary to switch the power switch related to the fluorescent tube, and the newly installed fluorescent tube can be automatically detected and automatically lighted up, and thus avoiding a potentially hazard for the tube-replacing personnel who climbs up and down a ladder repeatedly.
In order to make the aforementioned and other features and advantages of the invention comprehensible, several exemplary embodiments accompanied with figures are described in detail below.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
In the present embodiment, a user can switch the power switch SW to turn on and turn off the fluorescent tube installed on the lamp holder LH. In other words, the driving apparatus composed of the conversion unit 101, the PFC unit 103, the driving unit 105, the detection unit 107 and the capacitor Cp drives the fluorescent tube installed on the lamp holder LH to emit light in response to an ON state of the power switch SW, and stops driving the fluorescent tube installed on the lamp holder LH in response to an OFF state of the power switch SW.
When the user wants to turn on the fluorescent tube (for example, the fluorescent tube FT1) installed on the lamp holder LH, the conversion unit 101 receives an alternating current (AC) power VAC in response to the ON state of the power switch SW, and converts the AC power VAC to provide a direct current (DC) power VDC. In detail, the conversion unit 101 may include a bridge rectifier BR and a filter capacitor CF. The bridge rectifier BR receives the AC power VAC, and performs a full-wave rectification or a half-wave rectification to the AC power VAC to provide the DC power VDC. The filter capacitor CF is coupled to the bridge rectifier BR for filtering the DC power VDC provided by the bridge rectifier BR, so as to reduce a ripple factor of the DC power VDC.
It should be noticed that according to an Energy-Star standard, an input power factor of a driving power of commercial illumination is not less than 0.9, and is not less than 0.7 for home illumination. Therefore, in the present embodiment, the PFC unit 103 is coupled to the conversion unit 101 for performing a power factor correction on the DC power VDC output by the conversion unit 101, so as to match the Energy-Star standard. Moreover, the driving unit 105 is coupled to the PFC unit 103, and generates an AC driving signal DAC with a high voltage (which generally has several hundreds volts) in response to an output of the PFC unit 103, so as to drive the fluorescent tube FT1 installed on the lamp holder LH.
Moreover, the detection unit 107 is coupled to the driving unit 105, and is used for detecting whether a high side filament HV and a low side filament LV of the fluorescent tube FT1 installed on the lamp holder LH are broken. When at least one of the high side filament HV and the low side filament LV of the fluorescent tube FT1 installed on the lamp holder LH is broken, the detection unit 107 makes the driving unit 105 to stop generating the AC driving signal DAC. Moreover, when the broken fluorescent tube FT1 originally installed on the lamp holder LH is replaced by a good fluorescent tube FT2, the detection unit 107 makes the driving unit 105 to regenerate the AC driving signal DAC to drive the newly installed fluorescent tube FT2, where the power switch SW is unnecessary to be switched.
In detail, the detection unit 107 includes a high voltage detection circuit 107a and a low voltage detection circuit 107b. The high voltage detection circuit 107a is coupled to the high side filament HV of the fluorescent tube FT1 for detecting whether the high side filament HV of the fluorescent tube FT1 is broken, and sending a first detecting signal DH having a first state (for example, a low potential, 0V) to the driving unit 105 when the high side filament HV of the fluorescent tube FT1 is broken, so as to make the driving unit 105 to stop generating the AC driving signal DAC, and sending the first detecting signal DH having a second state (for example, a high potential, which is about a system voltage VCC) to the driving unit 105 when the broken fluorescent tube FT1 originally installed on the lamp holder LH is replaced by the good fluorescent tube FT2, so as to make the driving unit 105 to regenerate the AC driving signal DAC to drive the newly installed fluorescent tube FT2.
Moreover, the low voltage detection circuit 107b is coupled to the low side filament LV of the fluorescent tube FT1 for detecting whether the low side filament LV of the fluorescent tube FT1 is broken, and sending a second detecting signal DL having the first state (for example, the low potential, 0V) to the driving unit 105 when the low side filament LV of the fluorescent tube FT1 is broken, so as to make the driving unit 105 to stop generating the AC driving signal DAC, and sending the second detecting signal DL having the second state (for example, the high potential, which is about the system voltage VCC) to the driving unit 105 when the broken fluorescent tube FT1 originally installed on the lamp holder LH is replaced by the good fluorescent tube FT2, so as to make the driving unit 105 to regenerate the AC driving signal DAC to drive the newly installed fluorescent tube FT2.
In the present embodiment, the high voltage detection circuit 107a includes a switching unit SWU, resistors R1 and R2, and a Zener diode ZD. A first terminal of the switching unit SWU is coupled to the system voltage VCC, a second terminal of the switching unit SWU is coupled to a first end of the high side filament HV of the fluorescent tube FT1, and the first end of the high side filament HV of the fluorescent tube FT1 further receives the AC driving signal DAC generated by the driving unit 105.
A first end of the resistor R1 is coupled to a second end of the high side filament HV of the fluorescent tube FT1 and a first end of the capacitor Cp. A cathode of the Zener diode ZD is coupled to a second end of the resistor R1, and an anode of the Zener diode ZD is coupled to a ground potential. A first end of the resistor R2 is coupled to the cathode of the Zener diode ZD and a control terminal of the switching unit SWU, and is used for generating the first detecting signal DH to the driving unit 105, and a second end of the resistor R2 is coupled to the ground potential.
In detail, the switching unit SWU may include a P-type transistor Q1 (for example, a PMOS transistor) and a resistor R3 as that shown in
Moreover, the low voltage detection circuit 107b includes resistors R4 and R5, a diode D1, a capacitor C1 and an N-type transistor Q2 (for example, an NMOS transistor). A first end of the resistor R4 is coupled to the system voltage VCC. A cathode of the diode D1 is coupled to a first end of the low side filament LV of the fluorescent tube FT1 and a second end of the capacitor Cp, an anode of the diode D1 is coupled to a second end of the resistor R4, and a second end of the low side filament LV of the fluorescent tube FT1 is coupled to the ground potential. A first end of the capacitor C1 is coupled to the anode of the diode D1, and a second end of the capacitor C1 is coupled to the ground potential. A gate of the N-type transistor Q2 is coupled to the first end of the capacitor C1, a source of the N-type transistor Q2 is coupled to the ground potential, and a drain of the N-type transistor Q2 is used for generating the second detecting signal DL to the driving unit 105. A first end of the resistor R5 is coupled to the system voltage VCC, and a second end of the resistor R5 is coupled to the drain of the N-type transistor Q2.
According to the above descriptions, when the fluorescent tube FT1 installed on the lamp holder LH is good, and the user switches the power switch SW to turn on the fluorescent tube FT1, the driving unit 105 generates the AC driving signal DAC with a relatively high voltage to drive the fluorescent tube FT1 to emit light. Moreover, the capacitor Cp may provide a high-enough starting voltage during a transient process of starting the fluorescent tube FT1, and provide a suitable filament current when the fluorescent tube FT1 stably operates. Under such condition, since the high side filament HV and the low side filament LV of the fluorescent tube FT1 are not broken, the P-type transistor Q1 and the N-type transistor Q2 are all turned off. In this way, the high voltage detection circuit 107a and the low voltage detection circuit 107b respectively send the first detecting signal DH of the high potential and the second detecting signal DL of the high potential to make the driving unit 105 to continually generate the AC driving signal DAC with the relatively high voltage to drive the fluorescent tube FT1 to emit light.
During a light emitting process of the fluorescent tube FT1, it is assumed that the high side filament HV is broken, and the low side filament LV is not broken. In this case, since the resistor R2 is coupled to the ground, the high voltage detection circuit 107a sends the first detecting signal DH of the low potential to the driving unit 105, so that the driving unit 105 stops generating the AC driving signal DAC. Meanwhile, the P-type transistor Q1 is turned on in response to the first detecting signal DH of the low potential, so that the system voltage VCC is transmitted to the first end of the high side filament HV of the fluorescent tube FT1.
When the broken fluorescent tube FT1 originally installed on the lamp holder LH is replaced by the good fluorescent tube FT2, since the high side filament HV of the fluorescent tube FT2 is not broken, the high voltage detection circuit 107a sends the first detecting signal DH of the high potential to the driving unit 105 in response to the system voltage VCC, so that the driving unit 105 regenerates the AC driving signal DAC to drive the newly installed fluorescent tube FT2, and the power switch SW is unnecessary to be switched. Meanwhile, the P-type transistor Q1 is turned off in response to the first detecting signal DH of the high potential, so as to avoid shifting the AC driving signal DAC generated by the driving unit 105 to damage the newly installed fluorescent tube FT2.
On the other hand, during the light emitting process of the fluorescent tube FT1, it is assumed that the high side filament HV is not broken, and the low side filament LV is broken. In this case, since the resistor R4 is coupled to the system voltage VCC, the N-type transistor Q2 is turned on, so that the low voltage detection circuit 107b sends the second detecting signal DL of the low potential to the driving unit 105, so that the driving unit 105 stops generating the AC driving signal DAC. When the broken fluorescent tube FT1 originally installed on the lamp holder LH is replaced by the good fluorescent tube FT2, since the low side filament LV of the fluorescent tube FT2 is not broken, the N-type transistor Q2 is turned off, so that the low voltage detection circuit 107b sends the second detecting signal DL of the high potential to the driving unit 105 in response to the system voltage VCC, so that the driving unit 105 regenerates the AC driving signal DAC to drive the newly installed fluorescent tube FT2.
According to the above descriptions, when the fluorescent tube is broken, the driving apparatus stops providing power to both ends of the broken fluorescent tube regardless of whether the power switch related to the fluorescent tube is in the ON state or the OFF state, and thus making sure that a tube-replacing personnel is under safety conditions without getting an electric shock during a process of replacing the broken fluorescent tube. Meanwhile, after the broken fluorescent tube is replaced, it is unnecessary to switch the power switch related to the fluorescent tube, and the newly installed fluorescent tube can be automatically detected and automatically lighted up, and thus avoiding a potentially hazard for the tube-replacing personnel who climbs up and down a ladder repeatedly.
According to the above descriptions,
An AC power is converted into a DC power (step S301).
A power factor correction is performed on the DC power (step S303).
An AC driving signal is generated in response to the power-factor corrected DC power (step S305), so as to drive a fluorescent tube installed on a lamp holder.
During a light emitting process of the fluorescent tube installed on the lamp holder, it is detected whether a high side filament and a low side filament of the fluorescent tube installed on the lamp holder are broken (step S307).
When at least one of the high side filament and the low side filament of the fluorescent tube installed on the lamp holder is broken, it is stopped generating the AC driving signal (step S309), otherwise, the step S305 is returned to continually drive the fluorescent tube installed on the lamp holder by the AC driving signal.
After generation of the AC driving signal is stopped, it is determined whether the broken fluorescent tube originally installed on the lamp holder is replaced by a good fluorescent tube (step S311).
When the broken first fluorescent tube originally installed on the lamp holder is replaced by the good fluorescent tube, the AC driving signal is regenerated (step S313) to drive the newly installed fluorescent tube, and the step S307 is returned. Otherwise (i.e. the broken fluorescent tube is still installed on the lamp holder), it is continuously stopped generating the AC driving signal.
In summary, in the driving apparatus of the fluorescent tube and the driving method thereof, when the fluorescent tube is broken, the driving apparatus stops providing power to both ends of the broken fluorescent tube regardless of whether the power switch related to the fluorescent tube is in an ON state or an OFF state, and thus making sure that a tube-replacing personnel is under safety conditions without getting an electric shock during a process of replacing the broken fluorescent tube with a good fluorescent tube. Meanwhile, after the broken fluorescent tube is replaced, it is unnecessary to switch the power switch related to the fluorescent tube, and the newly installed fluorescent tube can be automatically detected and automatically lighted up, and thus avoiding a potentially hazard for the tube-replacing personnel who climbs up and down a ladder repeatedly.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
---|---|---|---|
100100173 A | Jan 2011 | TW | national |
Number | Name | Date | Kind |
---|---|---|---|
5969483 | Li et al. | Oct 1999 | A |
6348769 | Pinchuk et al. | Feb 2002 | B1 |
7154232 | Contenti et al. | Dec 2006 | B2 |
20100001649 | Yamamoto et al. | Jan 2010 | A1 |
20110037401 | Yu | Feb 2011 | A1 |
20110062878 | Liess et al. | Mar 2011 | A1 |
Number | Date | Country |
---|---|---|
101690409 | Mar 2010 | CN |
2002528871 | Sep 2002 | JP |
200808124 | Feb 2008 | TW |
201026151 | Jul 2010 | TW |
201101931 | Jan 2011 | TW |
2009158330 | Dec 2009 | WO |
Entry |
---|
“Office Action of Taiwan Counterpart Application”, issued on Sep. 5, 2013, p. 1-p. 11. |
“Office Action of China Counterpart Application”, issued on Aug. 19, 2013, p. 1-p. 6. |
Number | Date | Country | |
---|---|---|---|
20120169233 A1 | Jul 2012 | US |