TWI399129B - Driving device for a light emitting diode circuit and related lighting device - Google Patents

Driving device for a light emitting diode circuit and related lighting device Download PDF

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Publication number
TWI399129B
TWI399129B TW98102014A TW98102014A TWI399129B TW I399129 B TWI399129 B TW I399129B TW 98102014 A TW98102014 A TW 98102014A TW 98102014 A TW98102014 A TW 98102014A TW I399129 B TWI399129 B TW I399129B
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TW
Taiwan
Prior art keywords
voltage
capacitor
coupled
unit
receiving end
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TW98102014A
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Chinese (zh)
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TW201029521A (en
Inventor
jian shen Li
Chia Chieh Hung
Shih Min Chen
Chun Liang Lin
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Grenergy Opto Inc
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Priority to TW98102014A priority Critical patent/TWI399129B/en
Publication of TW201029521A publication Critical patent/TW201029521A/en
Application granted granted Critical
Publication of TWI399129B publication Critical patent/TWI399129B/en

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Description

Driving device and related lighting device for a light emitting diode circuit

The present invention relates to a driving device and related lighting device for a light-emitting diode circuit, and more particularly to a driving device and related lighting device having a dimming function and storing a power through a capacitor to supply a dimming function.

In daily life, people often need to change the brightness of the light depending on the environment. When using traditional lighting devices such as light bulbs or fluorescent lamps, the user usually switches the number of lighting lights through a multi-segment switch to adjust the appropriate brightness, such as softer light for dining or brighter light when reading.

Light Emitting Diode has the advantages of power saving, long life and high brightness. It has become popular in many lighting applications in recent years, such as indicator lights or flashlights. Please refer to FIG. 1 , which is a schematic diagram of a lighting device 10 of a conventional light-emitting diode. The illumination device 10 is a multi-segment brightness illumination device comprising a light-emitting diode circuit 100, a microcontroller 102 and a Pulse Width Modulation control unit 104. The power required for the lighting device 10 is supplied by an input power source VCC. The microcontroller 102 generates a control signal Vctrl corresponding to a specific brightness to the pulse width modulation control unit 104. The pulse width modulation control unit 104 generates a pulse width modulation signal Vpwm according to the control signal Vctrl for controlling the current of the LED circuit 100, thereby adjusting the brightness of the illumination device 10.

As can be seen from the above, the brightness adjustment of the illumination device 10 is controlled by the microcontroller 102. When a conventional lighting device such as a fluorescent lamp is used, the user switches the brightness of the light through the switch. In contrast, the lighting device 10 of the light-emitting diode is not as easy to switch the brightness as the fluorescent lamp, and the cost required by the microcontroller 102 is high. Therefore, the light-emitting diode cannot completely replace the traditional light bulb or fluorescent lamp.

Accordingly, it is a primary object of the present invention to provide a driving device and associated lighting device for a light emitting diode circuit.

The invention discloses a driving device for a light-emitting diode circuit, comprising a power receiving end coupled to a switch for receiving a DC power through the switch, the DC power source for providing the LED circuit And a power source required for the operation of the driving device; a capacitor coupled to the power receiving end for storing power; and a dimming unit coupled to the power receiving end and the capacitor for the voltage of the capacitor When the falling does not reach a first threshold, a control signal is generated according to the closing condition of the switch to adjust the brightness state of the LED circuit.

The invention further discloses a lighting device comprising a light emitting diode circuit, a switch and a driving device. The LED circuit includes at least one light emitting diode. The switch is coupled to an AC power source for controlling an output of the AC power source, wherein the AC power source is used to provide power required for operation of the lighting device. The driving device includes a power receiving end coupled to the switch for receiving a DC power converted by the AC power through the switch; a capacitor coupled to the power receiving end for storing power; The unit is coupled to the LED circuit for adjusting an operating current of the LED circuit according to a control signal to drive the LED circuit to generate a light source, and a dimming unit coupled to the LED The power receiving end, the capacitor and the control unit are configured to generate the control signal according to the closed condition of the switch when the voltage drop of the capacitor does not reach a first threshold to adjust the brightness of the LED circuit status.

Please refer to FIG. 2, which is a schematic diagram of a lighting device 20 according to an embodiment of the present invention. The illumination device 20 is powered by a light-emitting diode, and the power required for its operation is provided by an AC power source VCC. The illumination device 20 includes a light-emitting diode circuit 200, a switch 202, a driving device 204, and a power converter. The circuit and operation principle of the power converter are well known in the art, and are omitted in the present invention and the drawings. The AC power source VCC is connected to the power converter via the switch 202, and the power required by the driving device 204 is obtained by the conversion circuit. The power converter also supplies the energy required for the LED circuit 200. The LED circuit 200 is composed of a plurality of LEDs connected in series and connected in parallel. The switch 202 is coupled to the AC power source VCC for controlling the output of the AC power source VCC to the illumination device 20. The user controls the LED circuit 200 to generate a light source by turning on and off the switch 202. The driving device 204 is used to drive the LED circuit 200 and adjust the brightness state of the light source generated by the LED circuit 200, as described in detail below.

The driving device 204 includes a power receiving terminal VIN, a capacitor 210, a dimming unit 212, and a control unit 216. The power receiving terminal VIN is coupled to the power converter. When the switch 202 is turned on, the power converter will provide the DC power required by the driving device 204. The capacitor 210 is coupled to the power receiving terminal VIN for storing power. The dimming unit 212 is coupled to the power receiving end VIN and the capacitor 210 for reducing the voltage of the capacitor 210 by a threshold value VTH1 (ie, the lower voltage limit required for the dimming unit 212 to maintain operation). In the off situation, a control signal SC is generated to the control unit 216. The control unit 216 is coupled to the dimming unit 212 and the LED circuit 200 for adjusting the operating current of the LED circuit 200 or adjusting the number of LEDs to drive the LED according to the control signal SC. The polar body circuit 200 produces light sources of different brightness states, such as full bright, semi-bright, and slightly bright. The control unit 216 can be designed to adjust the operating current of the LED circuit 200 or to adjust the amount of lighting of the LED, the implementation of which is not limited to the scope of the invention.

It should be noted that the driving device 204 of the embodiment of the present invention is a driving device having a multi-stage dimming function, and the user can control the dimming unit 212 to realize the multi-stage dimming function through the opening and closing of the switch 202. The dimming unit 212 includes a detecting unit 220 and a counting unit 222. The detecting unit 220 is coupled to the power receiving end VIN and the capacitor 210 for generating a detecting signal SD according to the closing condition of the switch 202 when the voltage drop of the capacitor 210 does not reach the threshold value VTH1. When the switch 202 is turned off, the voltage detected by the detecting unit 220 is decreased; when the voltage detected by the detecting unit 220 drops to a threshold value VTH2, the voltage level of the detecting signal SD changes, such as by a high potential. Switch to low potential. The counting unit 222 is coupled to the detecting unit 220, the capacitor 210 and the control unit 216 for maintaining the operation of the power stored in the capacitor 210 when the switch 202 is turned off but the voltage of the capacitor 210 has not fallen below the threshold value VTH1. The number of times the signal SD transitions from a high potential to a low potential to generate a control signal SC corresponding to the appropriate brightness state. For example, before the voltage of the capacitor 210 has not yet fallen below the threshold VTH1, the switch 202 is switched three times by the user. At this time, the counting unit 222 accumulates the detection signal SD from high potential to low potential for three times, counting The control signal SC generated by the unit 222 will control the LED circuit 200 to operate in a night light mode.

In practice, the detecting unit 220 can be a voltage detector (Voltage Detector), and the threshold value VTH2 is a reference voltage of the voltage detector. When the detected voltage of the detecting unit 220 is higher than the threshold value VTH2, the detecting unit 220 outputs a high potential signal; when the detected voltage of the detecting unit 220 is lower than the threshold value VTH2, the detecting unit 220 outputs a low level. Potential signal. In addition, the operating voltage of the detecting unit 220 and the operating voltage of the counting unit 222 must be designed to be different voltages to prevent the voltage of the capacitor 210 from being misjudged by the detecting signal SD when the switch 202 is turned off.

When the switch 202 is turned off, the DC power source is not output to the dimming unit 212, and the illumination device 20 does not generate a light source. At this time, the capacitor 210 supplies power to the detecting unit 220 and the counting unit 222. During the period when the voltage of the capacitor 210 begins to decrease but has not reached the threshold value VTH1, the detection unit 220 outputs a low potential detection signal SD to the counting unit 222 every time the switch 202 is turned off. The counting unit 222 accumulates the number of times the detection signal SD is switched from the high potential to the low potential to generate the control signal SC corresponding to the appropriate brightness state. When the switch 202 is turned on again, the control unit 216 adjusts the operating current of the LED circuit 200 according to the control signal SC to drive the LED circuit 200 to generate a light source of appropriate brightness. Please refer to FIG. 3 and FIG. 4 . FIG. 3 and FIG. 4 show the relationship between the voltage measured by the detecting unit 220 and the detection signal SD in different situations in different situations. The voltage detection point of the detecting unit 220 is the end point of the capacitor 210; the threshold value VTH1 is the lower voltage limit required for the dimming unit 212 to maintain the operation, that is, the voltage at which the counting unit 222 is reset; the threshold value VTH2 is the detecting unit. 220 reference voltage. As can be seen from FIG. 3, when the voltage measured by the detecting unit 220 drops to the threshold value VTH2 but does not reach the threshold value VTH1, the detecting unit 220 generates the detecting signal SD according to the closing condition of the switch 202. In addition, as can be seen from FIG. 4, if the switch 202 is not turned on after being turned off for a period of time, and the voltage of the capacitor 210 falls below the threshold value VTH1, the counting unit 222 is reset, and the brightness state returns to a preset value.

The illumination device of the conventional light-emitting diode controls the multi-segment brightness state of the illumination device through the microcontroller, but the cost of the microcontroller is expensive. In contrast, the embodiment of the present invention achieves the same multi-segment switching effect through simple and low-cost components such as the detecting unit 220 and the counting unit 222, thereby greatly reducing the cost of the lighting device 20. At the same time, when the switch 202 of the illumination device 20 is turned off, the amount of power stored by the capacitor 210 is sufficient to maintain the operation of the counting unit 222. In effect, drive 204 is an LED driven wafer. In order to reduce the size of the chip, the capacitor 210 is usually disposed outside the wafer; at the same time, in order to reduce the component cost, the detection point of the detecting unit 220 is designed as the end point of the capacitor 210, so the driving device 204 only needs to provide a pin connection capacitor 210. At the same time, the voltage is detected.

It is worth noting that the amount of power stored in the capacitor 210 is actually limited; in addition, the voltage of the DC power source generated by the power converter may exceed the operating voltage range of the dimming unit 212. Accordingly, the present invention further provides a lighting device 50. Please refer to FIG. 5, which is a schematic diagram of the illumination device 50. The illuminating device 50 is similar to the illuminating device 20 of FIG. 2, and includes voltage regulators 500 and 502 in addition to the LED circuit 200, the switch 202, and the driving device 204. The voltage regulator 500 is coupled between the power receiving terminal VIN and the dimming unit 212, and more specifically, between the power receiving terminal VIN and the counting unit 222. Here, the voltage regulator 500 is used as a one-way conducting component for enabling the power stored in the capacitor 210 to be used more economically when the switch 202 is turned off, thereby preventing the counting unit 222 from being reset too quickly. The regulator 500 can also be replaced with a one-way element such as a diode or a transistor. The voltage regulator 502 is coupled between the DC power source generated by the power converter and the power receiving terminal VIN to generate an operating voltage suitable for the dimming unit 212. Please refer to FIG. 6 and FIG. 7 , which show the relationship between the voltage measured by the detecting unit 220 and the detection signal SD in FIG. 5 in different situations. Please note that the voltage detection point of the detecting unit 220 in FIG. 2 is the end point of the capacitor 210, and the voltage detecting point of the detecting unit 220 in FIG. 5 is the power receiving end VIN, so the detecting unit 220 The measured voltage is different from the voltage of the capacitor 210. The changes of the voltages, that is, the signals in FIGS. 6 and 7 are similar to those in FIGS. 3 and 4, and are not described here.

In the second embodiment, the embodiment of the present invention assumes that the operating voltages of the counting unit 222 and the control unit 216 are the same. Therefore, the voltage output by the detecting unit 220 is supplied to the control unit 216 in addition to the supply counting unit 222. Please refer to FIG. 8. FIG. 8 is a schematic diagram of a lighting device 80 according to an embodiment of the present invention. The illuminating device 80 is similar to the illuminating device 20 of FIG. 2, and further includes a voltage regulator 800 and a voltage detector 802. The function of the voltage regulator 800 is the same as that of the voltage regulator 502 of FIG. In FIG. 6, the embodiment of the present invention assumes that the operating voltage of the voltage detector 802 is higher than the operating voltage of the detecting unit 220 and the counting unit 222; when the switch 202 is turned on, the DC power generated by the power converter transmits voltage detection. The detector 802 provides the operating state and voltage required by the control unit 216, and the detecting unit 220 no longer provides the operating state and voltage to the control unit 216. As a result, when the switch 202 is turned off, the voltage of the power receiving terminal VIN drops, and the voltage detector 802 is turned off first. At this time, the amount of power stored in the capacitor 210 is only supplied to the counting unit 222, so that the lighting device 80 does not need to use a single By guiding the components, the purpose of saving the power of the capacitor 210 can be achieved.

Both the illuminating device 50 and the illuminating device 80 are embodiments of the present invention, and those skilled in the art can make various changes and modifications. Components such as single-pass components, voltage regulators, and voltage detectors can be used as needed. In the illuminating devices 20, 50 and 80, the counting unit 222 is coupled to the detecting unit 220 to receive the detecting signal SD. The detecting unit 220 receives the power through the power receiving terminal VIN and detects the opening and closing of the switch 202. In other embodiments of the present invention, the AC power supply at the back end of the switch 202 can also be directly taken, and the detection signal is generated after being processed. In addition, the detection signal of the detecting unit 220 is coupled to the power receiving terminal VIN, and can be coupled to any suitable position in the circuit between the switch 202 and the power receiving terminal VIN to detect the switch 202. Open and close.

In summary, the embodiment of the present invention implements a dimming function by using a simple and low-cost circuit such as a detecting unit and a counting unit. Preferably, the embodiment of the present invention stores the power through the capacitor to maintain the operation of the counting unit when the switch of the lighting device is turned off. In addition, the embodiment of the present invention applies components such as a single-pass component, a voltage regulator, and a voltage detector to extend the use time of the power of the capacitor, thereby preventing the brightness state of the illumination device from being reset prematurely, thereby improving the convenience of use.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10, 20, 50, 80. . . Lighting device

200. . . Light-emitting diode circuit

202. . . switch

204. . . Drive unit

210. . . capacitance

212. . . Dimming unit

216. . . control unit

220. . . Detection unit

222. . . Counting unit

500, 502, 800. . . Stabilizer

802. . . Voltage detector

VCC. . . AC power

VIN. . . Power receiving end

SC, Vctrl. . . Control signal

SD. . . Detection signal

Vpwm. . . Pulse width modulation signal

Figure 1 is a schematic view of a conventional lighting device.

2, 5, and 8 are schematic views of a lighting device according to an embodiment of the present invention.

Figure 3 and Figure 4 are diagrams showing the relationship between the voltage measured by the detection unit of the illumination device and the detection signal in Figure 2.

Fig. 6 and Fig. 7 are diagrams showing the relationship between the voltage, the voltage of the capacitor and the detection signal measured by the detecting unit of the lighting device in Fig. 5.

20. . . Lighting device

200. . . Light-emitting diode circuit

202. . . switch

204. . . Drive unit

210. . . capacitance

212. . . Dimming unit

216. . . control unit

220. . . Detection unit

222. . . Counting unit

VCC. . . AC power

VIN. . . Power receiving end

SC. . . Control signal

SD. . . Detection signal

Claims (19)

  1. A driving device for a light-emitting diode circuit includes: a power receiving end coupled to a switch for receiving a DC power through the switch, the DC power source for providing the LED circuit and The power supply required for the operation of the driving device; a capacitor coupled to the power receiving end for storing power; and a dimming unit coupled to the power receiving end and the capacitor for voltage drop of the capacitor When a first threshold is not reached, a control signal is generated to adjust the brightness state of the LED circuit according to the off condition of the switch.
  2. The driving device of claim 1, wherein the dimming unit further comprises: a detecting unit coupled to the power receiving end and the capacitor, wherein the voltage drop of the capacitor does not reach the first critical value A detection signal is generated according to the closing condition of the switch; and a counting unit is coupled to the detecting unit and the capacitor for generating the control signal according to the detecting signal.
  3. The driving device of claim 2, wherein the detecting unit generates the voltage when the voltage drop of the capacitor does not reach the first threshold and the voltage detected by the detecting unit drops to a second threshold Detection signal.
  4. The driving device of claim 2, wherein the counting unit is reset when the voltage of the capacitor drops to the first threshold.
  5. The driving device of claim 1, wherein the first critical value is a minimum value of an operating voltage of the dimming unit.
  6. The driving device of claim 1, further comprising a control unit coupled between the dimming unit and the LED circuit for adjusting the operation of the LED circuit according to the control signal A current is generated to drive the light emitting diode circuit to generate a light source.
  7. The driving device of claim 6, further comprising a voltage detector coupled to the power receiving end and the control unit, configured to output the DC power to the power receiving end when the voltage is greater than a reference voltage The control unit.
  8. The driving device of claim 1, further comprising a voltage regulator coupled between the DC power source and the power receiving end for generating an operating voltage of the dimming unit.
  9. The driving device of claim 1, further comprising a one-way conducting component coupled between the power receiving end and the dimming unit.
  10. The driving device of claim 9, wherein the one-way conducting component is a voltage regulator or a diode.
  11. A lighting device includes: a light emitting diode circuit including at least one light emitting diode; a switch coupled to an alternating current power source for controlling an output of the alternating current power source, wherein the alternating current power source is used to provide The power supply required for the operation of the illumination device; and a driving device comprising: a power receiving end coupled to the switch for receiving the DC power converted by the AC power source through the switch; a capacitor coupled The power receiving end is configured to store the power; a control unit is coupled to the LED circuit for adjusting the operating current of the LED circuit according to a control signal to drive the LED circuit Generating a light source; and a dimming unit coupled to the power receiving end, the capacitor, and the control unit, configured to generate the voltage according to a shutdown condition of the switch when the voltage drop of the capacitor does not reach a first threshold Controlling the signal to adjust the brightness state of the LED circuit.
  12. The lighting device of claim 11, wherein the dimming unit further comprises: a detecting unit coupled to the power receiving end and the capacitor, wherein the voltage drop of the capacitor does not reach the first critical value A detection signal is generated according to the closing condition of the switch; and a counting unit is coupled to the detecting unit and the capacitor for generating the control signal according to the detecting signal.
  13. The illuminating device of claim 12, wherein the detecting unit generates the voltage when the voltage drop of the capacitor does not reach the first threshold and the voltage detected by the detecting unit drops to a second threshold Detection signal.
  14. The lighting device of claim 12, wherein the counting unit is reset when the voltage of the capacitor drops to the first threshold.
  15. The lighting device of claim 11, wherein the first threshold is a minimum value of an operating voltage of the dimming unit.
  16. The lighting device of claim 11, further comprising a voltage detector coupled to the power receiving end and the control unit, configured to output the DC power to the power receiving end when the voltage is greater than a reference voltage The control unit.
  17. The lighting device of claim 11, further comprising a voltage regulator coupled between the DC power source and the power receiving end for generating an operating voltage of the dimming unit.
  18. The illuminating device of claim 11, further comprising a unidirectional conduction component coupled between the power receiving end and the dimming unit.
  19. The illuminating device of claim 18, wherein the unidirectional conduction component is a voltage regulator or a diode.
TW98102014A 2009-01-20 2009-01-20 Driving device for a light emitting diode circuit and related lighting device TWI399129B (en)

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Application Number Priority Date Filing Date Title
TW98102014A TWI399129B (en) 2009-01-20 2009-01-20 Driving device for a light emitting diode circuit and related lighting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
TW98102014A TWI399129B (en) 2009-01-20 2009-01-20 Driving device for a light emitting diode circuit and related lighting device

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TW201029521A TW201029521A (en) 2010-08-01
TWI399129B true TWI399129B (en) 2013-06-11

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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI491305B (en) * 2012-12-14 2015-07-01 碩頡科技股份有限公司 Load driving apparatus and driving method
TWI589187B (en) * 2016-01-28 2017-06-21 中興保全股份有限公司 Energy-saving lighting control board

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5216585A (en) * 1991-05-01 1993-06-01 Sony Corporation Switching power source device
TW575849B (en) * 2002-01-18 2004-02-11 Chi Mei Optoelectronics Corp Thin film transistor liquid crystal display capable of adjusting its light source
TWI252062B (en) * 2005-04-20 2006-03-21 Himax Tech Inc Method for driving a fluorescent lamp and inverter circuit for performing such a method
TWM289013U (en) * 2005-10-18 2006-03-21 System General Corp A control circuit and a controller for a light-emitting unit
TW200728849A (en) * 2006-01-20 2007-08-01 Niko Semiconductor Co Ltd Backlight power supply device of liquid crystal display panel

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5216585A (en) * 1991-05-01 1993-06-01 Sony Corporation Switching power source device
TW575849B (en) * 2002-01-18 2004-02-11 Chi Mei Optoelectronics Corp Thin film transistor liquid crystal display capable of adjusting its light source
TWI252062B (en) * 2005-04-20 2006-03-21 Himax Tech Inc Method for driving a fluorescent lamp and inverter circuit for performing such a method
TWM289013U (en) * 2005-10-18 2006-03-21 System General Corp A control circuit and a controller for a light-emitting unit
TW200728849A (en) * 2006-01-20 2007-08-01 Niko Semiconductor Co Ltd Backlight power supply device of liquid crystal display panel

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