CN101179879A - Luminous device and driving circuit - Google Patents
Luminous device and driving circuit Download PDFInfo
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- CN101179879A CN101179879A CNA2006101435379A CN200610143537A CN101179879A CN 101179879 A CN101179879 A CN 101179879A CN A2006101435379 A CNA2006101435379 A CN A2006101435379A CN 200610143537 A CN200610143537 A CN 200610143537A CN 101179879 A CN101179879 A CN 101179879A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Abstract
The invention relates to a driving circuit of a light emitting diode (LED) which comprises a power supply conversion module and a protection module. Wherein, the power supply conversion module is able to displace upward or downward an electrical potential of an input voltage according to an operation cycle of a pulse width modulation signal to output a driving signal to drive the LED. Moreover, the protection module bases on the electric potential of the driving signal to determine a state of a protection signal with a purpose of controlling the operation of the power supply conversion module. When the electric potential of the driving signal is above a first default value or is below a second default value, the protection signal is a first electric level to cause the power supply conversion module to stop outputting the driving signal. And when the electric potential of the driving signal is not above the first default value or is not below the second default value, the protection signal is a second electric level to ensure a regular operation of the power supply conversion module.
Description
Technical field
The present invention relates to a kind of drive circuit of light source, particularly relate to a kind of drive circuit of light-emitting diode.
Background technology
Light-emitting diode (Light Emitting Diode, be called for short LED) can convert electric energy to luminous energy, is used in gradually in the backlight module of various illumination places or consumer products as required light source.In general, can provide comparatively stable light source, can design the power supply changeover device of a DC-DC usually, to provide a galvanic current source to light-emitting diode in order to make light-emitting diode.
Fig. 1 shows the circuit diagram of existing DC-DC power supply converter.Please refer to Fig. 1, existing power supply changeover device 100 comprises inductance 102, transistor 104, diode 106 and electric capacity 108.Wherein, a termination of inductance 102 is received an input voltage VIN 1, and the other end is coupled to the first source/drain electrode end of transistor 104, and couples the anode tap of diode 106, and the cathode terminal of diode 106 then is by electric capacity 108 ground connection.In addition, second source of transistor 104/drain electrode end ground connection, its gate terminal then receives a pulse-width modulation signal SP1, and work period of pulse-width modulation signal wherein then is that the operating current of the light-emitting diode that driven according to power supply changeover device 100 determines.
When pulse-width modulation signal SP1 is high potential, transistor 104 is conducting, this moment, inductance 102 began to store the electric power that input voltage VIN 1 is transmitted, and the current potential of inductance 102 and the node of diode 106 is because the relation of coupling ground connection, and diode 106 is a closed condition.When pulse-width modulation signal SP1 is electronegative potential, transistor 104 is for closing, and the afterflow characteristic of inductance 102 makes the node potential raising with diode 106 at this moment, and making diode 106 conductings, the energy that is stored in inductance 102 begins to be sent to electric capacity 108 and stores and the driven for emitting lights led lighting.When pulse-width modulation signal SP1 became high potential again, electric capacity 108 discharges stored energy, and that light-emitting diode is continued was luminous, and inductance 102 once again storage power so that pass to the level led usefulness of electric capacity 108 next time again.So go round and begin again, and provide the voltage that is higher than input voltage VIN 1 with the driven for emitting lights diode.
For instance, VIN=12V can provide the driving signal that is higher than 12V DS1, the about 3.5V of the critical voltage of white light emitting diode through power supply changeover device 100.When light-emitting diode is four (or more than) series connection, need the driving signal DS1 of 14V (or more than), above-mentioned booster power transducer 100 can provide.So, when needs drove the light-emitting diode of three (or following) series connection, booster power transducer 100 just can't be competent at.
Though existing power supply changeover device can convert the current potential of input voltage to higher current potential, yet the current potential of input voltage can not be converted to lower current potential.Therefore in some technology, can use reduction voltage circuit to be used as power supply changeover device.But no matter be with booster circuit or reduction voltage circuit, all can't satisfy the demand the simultaneously load of high voltage and the load that needs low voltage.
Summary of the invention
Therefore, purpose of the present invention is exactly that a kind of drive circuit of light-emitting diode is being provided, and needs the LED load of high voltage and needs the LED load of low voltage all applicable for driving.
Therefore, the invention provides a kind of drive circuit of light-emitting diode, comprise one first inductance, one first electric capacity, a switch, one second inductance, a diode, one second electric capacity, a load sensor and a signal generation unit.First end of this first inductance couples an input voltage, and first end of this first electric capacity couples second end of this first inductance.This switch determines whether second end of this first inductance is coupled ground according to a pulse-width modulation signal.First end of this second inductance couples second end of this first electric capacity, and the second end ground connection of this second inductance.The anode tap of this diode couples second end of this first electric capacity, first end of this second electric capacity couples the cathode terminal and a light source module of this diode, to provide this light source module one to drive signal, second end of this second electric capacity is ground connection then, and wherein this light source module has at least one light-emitting diode.This load sensor detects the electric current of this light source module to export a back coupling signal.This signal generation unit couples this load sensor, and according to this back coupling signal to produce this pulse-width modulation signal.This drive circuit can comprise also whether a protection module determines whether the output protection signal greater than one first default value with less than one second default value according to the current potential that drives signal, drives signal so that power transfer module stops output.
From another viewpoint, the invention provides a kind of light-emitting device, comprise light source module, power transfer module and protection module.Wherein, light source module comprises a light-emitting diode at least, and power transfer module then is the work period according to a pulse-width modulation signal, and an input voltage is boosted or step-down becomes one to drive signal and come the driving light source module.In addition, protection module then is according to the current potential that drives signal, decides the state of a protection signal, with the running of control power transfer module.
Because the power transfer module among the present invention can promote the current potential of input voltage according to the work period of pulse-width modulation signal or reduce.Therefore, the present invention can satisfy the demand simultaneously high voltage LED load or need the LED load of low voltage.
For above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and be described with reference to the accompanying drawings as follows.
Description of drawings
Fig. 1 shows the circuit diagram of existing DC-DC power supply converter.
Fig. 2 shows the circuit diagram according to a kind of light-emitting device of a preferred embodiment of the present invention.
Fig. 3 shows the sequential chart according to a kind of pulse-width modulation signal of a preferred embodiment of the present invention.
Fig. 4 shows the circuit diagram according to a kind of signal generation unit of a preferred embodiment of the present invention.
Fig. 5 (a)-(d) shows the sequential chart according to the defencive function of a preferred embodiment of the present invention.
The reference numeral explanation
100: power supply changeover device
102,222,228: inductance
104,224: transistor
106,230: diode
108,226,232: electric capacity
200: light-emitting device
210: drive circuit
212: power transfer module
214: protection module
216,2162: the signal generation unit
233,234,266: resistance
236: comparing unit
260: light source module
262: light-emitting diode
264: load sensor
412: error amplifier
414: pulse-width modulation (PWM)
DS1: drive signal
FB: back coupling signal
SE: protection signal
SF: voltage detecting signal
SP1, SP2: pulse-width modulation signal
VIN1, VIN2: input voltage
Vref: reference voltage
Embodiment
Fig. 2 shows the circuit diagram according to a kind of light-emitting device of a preferred embodiment of the present invention.Please refer to Fig. 2, in light-emitting device 200 provided by the present invention, comprise drive circuit 210 and light source module 260.In the present invention, drive circuit 210 can come driving light source module 260 by generation driving signal DS2 according to an input voltage VIN 2.In the present embodiment, light source module 260 comprises a light-emitting diode at least.
In the present embodiment, light source module 260 comprises a plurality of (or at least one) light-emitting diode 262.The cathode terminal of each light-emitting diode all is coupled to the anode tap of next light-emitting diode, and the anode tap of first light-emitting diode then couples drive circuit 210, drives signal DS2 to receive.
Select among the embodiment at some, light source module 260 also comprises load sensor 264, and it is with the cathode terminal ground connection of last light-emitting diode.Load sensor 264 is in order to detect the operating current of the light-emitting diode 262 of flowing through, and can be converted into the back coupling signal FB of voltage kenel, is resent to signal generation unit 216.In the present embodiment, load sensor 264 can utilize resistance 266 to realize.Wherein, an end ground connection of resistance 266, the other end then couples the cathode terminal of last light-emitting diode.
In addition, the protection signal SE that back coupling signal FB that 216 of signal generation units can be produced by light source module 260 according to reception and protection module 214 are exported gives power transfer module 212 to produce pulse-width modulation signal SP2.By this, power transfer module 212 just can be according to the work period of pulse-width modulation signal SP2, and the current potential of input voltage VIN 2 is promoted or reduces, and drives signal DS2 to produce.
In addition, an end and the inductance 222 of electric capacity 226 are coupled to switch 224 jointly, and the other end of electric capacity 226 then is coupled to the anode tap of diode 230 and an end of inductance 228, the other end ground connection of inductance 228.In the present embodiment, diode 230 can be a Schottky diode, and an end of its cathode terminal coupling capacitance 232, the other end ground connection of electric capacity 232.
Fig. 3 shows the sequential chart according to a kind of pulse-width modulation signal of a preferred embodiment of the present invention.Please merge with reference to Fig. 2 and Fig. 3, suppose that power transfer module 212 has been in steady state operation, during time interval T1, pulse-width modulation signal SP2 is a high potential state, makes switch 224 conductings.At this moment, input voltage VIN 2 can make inductance 222 storage power to inductance 222 chargings, and electric capacity 226 also discharges stored energy via switch 224, and is stored to inductance 228.Wherein diode is a closed condition, and 232 of electric capacity release energy luminous with driving light source module 260.
During time interval T2, pulse-width modulation signal SP2 is a low-potential state, makes switch 224 close (Trun Off).At this moment, inductance 222,228 can release energy, driving light source module 260 luminous (this moment, diode 230 was a conducting state), and electric capacity 226,232 stores the energy of 222,228 release portions of inductance, with the stable voltage that offers the driving signal DS2 of light source module 260.
During time interval T3, pulse-width modulation signal SP2 becomes high potential once again, makes switch 224 conducting once more.At this moment, inductance 222,228 is once again for the energy storage state, and electric capacity 226,232 can state for releasing, and wherein the electric energy that electric capacity 232 will be stored discharges, and continues to export driving signal DS2.
In the present invention, the ratio of the current potential of driving signal DS2 and the current potential of input voltage VIN 2, can express with following formula:
Wherein D represents the work period of pulse-width modulation signal SP2.That is to say that when work period of pulse-width modulation signal SP2 greater than 50% time (for example work period of pulse-width modulation signal SP2 during time interval T4 among Fig. 3), power-switching circuit 212 can promote the current potential of input voltage VIN 2.Relatively, when work period of pulse-width modulation signal SP2 less than 50% time (for example work period of pulse-width modulation signal SP2 during time interval T5 among Fig. 3), power-switching circuit 212 can reduce the current potential of input voltage VIN 2.By this, the present invention only needs to adjust the cycle of pulse-width modulation signal, just can satisfy the light source module of different voltage requirements.
Referring again to Fig. 2, protection module 214 comprises with resistance 233 and 234 voltage detector circuit of being formed and comparing unit 236.Resistance 233 and 234 is one another in series, and an end couples the cathode terminal of diode 230, and the other end then couples ground.In the present embodiment, resistance 233 and 234 the two node potential that couple can be sent to comparing unit 236, to send a voltage detecting signal SF.When comparing unit 236 receives voltage detecting signal SF, can give signal generation unit 216 by output protection signal SE according to voltage detecting signal SF.
In the present embodiment, voltage detecting signal SF is used to refer to the current potential that drives signal DS2.Therefore, when comparing unit 236 receives voltage detecting signal SF, can be according to voltage detecting signal SF, and whether the current potential that relatively drives signal DS2 is greater than one first default value or less than one second default value.
When the current potential that drives signal DS2 during, represent drive circuit 210 possible abnormal operations greater than first default value or less than second default value.Therefore; comparing unit 236 can be exported the protection signal SE with first level; interrupt the running of signal generation unit 216; make signal generation unit 216 stop output pulse width modulating signal SP2 and give power transfer module 212, drive signal DS2 to light source module 260 and cause power transfer module 212 to stop output.By this, just can avoid light source module 260 because the damage that abnormal operation causes of drive circuit 210.
Relatively, when the current potential that drives signal DS2 was between first default value and second default value, representing drive circuit 210 should be normal running.At this moment, (perhaps we can say and stop output) protection signal SE can be exported and had second level to comparing unit, makes signal generation unit 216 continue to produce pulse-width modulation signal SP2 and give power transfer module 212.Wherein, first level can be greater than second level.
Fig. 4 shows the circuit diagram according to a kind of comparing unit of a preferred embodiment of the present invention.Please refer to Fig. 4, comparing unit 2162 goes for the signal generation unit 216 among Fig. 2, and it has comprised error amplifier 412 and pulse-width modulation (PWM) 414.In the present embodiment, error amplifier 412 is used for receiving a back coupling signal FB and the reference voltage Vref that the light source module 260 of Fig. 2 is for example exported.After error amplifier 412 has received back coupling signal FB, itself and reference voltage Vref can be compared, and export a compensating signature and give pwm unit 414.
When feedbacking the current potential of signal FB during less than reference voltage Vref, pwm unit 414 can increase the work period of pulse-width modulation signal SP2.Relatively, when feedbacking the current potential of signal FB during greater than reference voltage Vref, pwm unit 414 can reduce the work period of pulse-width modulation signal SP2.By this, the present invention's light source module 260 among control example such as Fig. 2 effectively just.
Fig. 5 (a)-(d) shows the sequential chart according to the defencive function of a preferred embodiment of the present invention.Before time point t1, drive circuit 210 stably provides and drives signal DS2, and protection signal SE is in second level.So in time point t1, circuit abnormal causes the level that drives signal DS2 suddenly to improve.To between the t2, the level of back coupling signal FB also rises at time point t1, and signal generation unit 216 is according to feedbacking signal FB the work period that reduces pulse-width modulation signal SP2.In time point t2, voltage detecting signal SF is higher than one first value (i.e. representative drives signal DS2 and is higher than one first default value), and protection signal SE changes into first level and pins, and makes no longer output pulse width modulating signal SP2 of signal generation unit 216.Certainly, after protection signal SE changes into first level from second level, can also not pin, when voltage detecting signal SF got back between first value and second value, signal generation unit 216 is output pulse width modulating signal SP2 once again; Perhaps continue a scheduled time, voltage detecting signal SF continues greater than near first value (or less than second value) time, and protection signal SE just changes to first level and lock-bit.Pin in protection signal SE and must remove locking-in state through reseting in first level.
In sum, because in the present invention, power transfer module can promote the current potential of input voltage or reduces according to work period of pulse-width modulation signal.Therefore, the present invention can be suitable for the light source load of different voltage requirements.In addition, owing to have protection module in the present invention.Therefore, when abnormal operation of the present invention, can avoid causing load to damage.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; those skilled in the art can do some changes and retouching under the premise without departing from the spirit and scope of the present invention, so protection scope of the present invention is as the criterion with claim of the present invention.
Claims (12)
1. the drive circuit of a light-emitting diode comprises:
One first inductance, its first end couples an input voltage;
One first electric capacity, its first end couples second end of this first inductance;
One switch determines whether second end of this first inductance is coupled ground according to a pulse-width modulation signal;
One second inductance, its first end couples second end of this first electric capacity, and the second end ground connection of this second inductance;
One diode, its anode tap couple second end of this first electric capacity;
One second electric capacity, its first end couple the cathode terminal and a light source module of this diode, drive signal so that this light source module one to be provided, and second end of this second electric capacity is ground connection then, and wherein this light source module has at least one light-emitting diode;
One load sensor, the electric current that detects this light source module is to export a back coupling signal; And
One signal generation unit couples this load sensor, and according to this back coupling signal to produce this pulse-width modulation signal.
2. the drive circuit of light-emitting diode as claimed in claim 1; also comprise a protection module; couple this signal generation unit and according to the current potential of this driving signal; decide the state of a protection signal, make this signal generation unit more determine whether producing this pulse-width modulation signal according to this protection signal.
3. the drive circuit of light-emitting diode as claimed in claim 2, wherein when this current potential that drives signal during greater than one first default value or less than one second default value, this signal generation unit stops to export this driving signal.
4. the drive circuit of light-emitting diode as claimed in claim 2 is wherein worked as this current potential that drives signal in case greater than one first default value or less than one second default value, and this signal generation unit stops to export this driving signal.
5. the drive circuit of light-emitting diode as claimed in claim 2 wherein drives the current potential of signal in case continue a Preset Time greater than one first default value or less than one second default value when this, and this signal generation unit stops to export this driving signal.
6. as the drive circuit of the described light-emitting diode of arbitrary claim in the claim 3 to 5, wherein this signal generation unit comprises:
One error amplifier compared in order to should feedback a signal and a reference voltage, and produced a compensating signature; And
One pwm unit produces the pulse-width modulation signal according to the state of this protection signal and this compensating signature.
7. the drive circuit of light-emitting diode as claimed in claim 2, wherein this protection module comprises:
One voltage detector is in order to detect the current potential of this driving signal; And
One comparing unit compares in order to the current potential that will drive signal and one first value and one second value, and exports this protection signal.
8. light-emitting device comprises:
One light source module comprises a light-emitting diode at least;
One power transfer module was boosted an input voltage in order to the work period of foundation one pulse-width modulation signal or step-down becomes a driving signal to drive this light source module; And
One protection module in order to according to this current potential that drives signal, decides the state of a protection signal, to control the running of this power transfer module.
9. light-emitting device as claimed in claim 8, wherein when this current potential that drives signal during greater than one first default value or less than one second default value, then this protection module is exported this protection signal so that this power transfer module stops to export this driving signal.
10. light-emitting device as claimed in claim 8 is wherein worked as this current potential that drives signal in case greater than one first default value or less than one second default value, and then this protection module is exported this protection signal so that this power transfer module stops to export this driving signal.
11. light-emitting device as claimed in claim 8; wherein drive the current potential of signal in case continue a Preset Time greater than one first default value or less than one second default value when this, then this protection module is exported this protection signal so that this power transfer module stops to export this driving signal.
12. as the described light-emitting device of arbitrary claim in the claim 9 to 11, wherein this protection module comprises:
One voltage detector is in order to detect the current potential of this driving signal; And
One comparing unit drives the current potential of signal and the comparative result of this first default value and this second default value according to this, and exports this protection signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2006101435379A CN101179879A (en) | 2006-11-10 | 2006-11-10 | Luminous device and driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2006101435379A CN101179879A (en) | 2006-11-10 | 2006-11-10 | Luminous device and driving circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101179879A true CN101179879A (en) | 2008-05-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2006101435379A Pending CN101179879A (en) | 2006-11-10 | 2006-11-10 | Luminous device and driving circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101179879A (en) |
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102014540A (en) * | 2010-03-04 | 2011-04-13 | 凹凸电子（武汉）有限公司 | Drive circuit and controller for controlling electric power of light source |
| US8330388B2 (en) | 2008-12-12 | 2012-12-11 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US8339067B2 (en) | 2008-12-12 | 2012-12-25 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US8378589B2 (en) | 2008-12-12 | 2013-02-19 | O2Micro, Inc. | Driving circuit with dimming controller for driving light sources |
| US8378588B2 (en) | 2008-12-12 | 2013-02-19 | O2Micro Inc | Circuits and methods for driving light sources |
| US8508150B2 (en) | 2008-12-12 | 2013-08-13 | O2Micro, Inc. | Controllers, systems and methods for controlling dimming of light sources |
| US8698419B2 (en) | 2010-03-04 | 2014-04-15 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US8866398B2 (en) | 2012-05-11 | 2014-10-21 | O2Micro, Inc. | Circuits and methods for driving light sources |
| CN104159365A (en) * | 2014-07-22 | 2014-11-19 | 合肥鑫晟光电科技有限公司 | Backlight circuit and backlight with same |
| US9030122B2 (en) | 2008-12-12 | 2015-05-12 | O2Micro, Inc. | Circuits and methods for driving LED light sources |
| US9232591B2 (en) | 2008-12-12 | 2016-01-05 | O2Micro Inc. | Circuits and methods for driving light sources |
| US9253843B2 (en) | 2008-12-12 | 2016-02-02 | 02Micro Inc | Driving circuit with dimming controller for driving light sources |
| US9386653B2 (en) | 2008-12-12 | 2016-07-05 | O2Micro Inc | Circuits and methods for driving light sources |
| CN105792415A (en) * | 2016-03-18 | 2016-07-20 | 明纬(广州)电子有限公司 | Dimming control apparatus |
| TWI650947B (en) * | 2017-12-22 | 2019-02-11 | 隆達電子股份有限公司 | Filter circuit and control system |
| CN112533320A (en) * | 2019-08-28 | 2021-03-19 | 群光电能科技股份有限公司 | Light emitting diode control device |
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2006
- 2006-11-10 CN CNA2006101435379A patent/CN101179879A/en active Pending
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| US9386653B2 (en) | 2008-12-12 | 2016-07-05 | O2Micro Inc | Circuits and methods for driving light sources |
| US9030122B2 (en) | 2008-12-12 | 2015-05-12 | O2Micro, Inc. | Circuits and methods for driving LED light sources |
| US8330388B2 (en) | 2008-12-12 | 2012-12-11 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US9253843B2 (en) | 2008-12-12 | 2016-02-02 | 02Micro Inc | Driving circuit with dimming controller for driving light sources |
| US8378589B2 (en) | 2008-12-12 | 2013-02-19 | O2Micro, Inc. | Driving circuit with dimming controller for driving light sources |
| US8378588B2 (en) | 2008-12-12 | 2013-02-19 | O2Micro Inc | Circuits and methods for driving light sources |
| US8508150B2 (en) | 2008-12-12 | 2013-08-13 | O2Micro, Inc. | Controllers, systems and methods for controlling dimming of light sources |
| US9232591B2 (en) | 2008-12-12 | 2016-01-05 | O2Micro Inc. | Circuits and methods for driving light sources |
| US8339067B2 (en) | 2008-12-12 | 2012-12-25 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US8698419B2 (en) | 2010-03-04 | 2014-04-15 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US8664895B2 (en) | 2010-03-04 | 2014-03-04 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US8339063B2 (en) | 2010-03-04 | 2012-12-25 | O2Micro Inc | Circuits and methods for driving light sources |
| CN102014540A (en) * | 2010-03-04 | 2011-04-13 | 凹凸电子（武汉）有限公司 | Drive circuit and controller for controlling electric power of light source |
| US8890440B2 (en) | 2010-03-04 | 2014-11-18 | O2Micro, Inc. | Circuits and methods for driving light sources |
| US8866398B2 (en) | 2012-05-11 | 2014-10-21 | O2Micro, Inc. | Circuits and methods for driving light sources |
| CN104159365B (en) * | 2014-07-22 | 2017-04-05 | 合肥鑫晟光电科技有限公司 | Backlight circuit and backlight |
| CN104159365A (en) * | 2014-07-22 | 2014-11-19 | 合肥鑫晟光电科技有限公司 | Backlight circuit and backlight with same |
| CN105792415A (en) * | 2016-03-18 | 2016-07-20 | 明纬(广州)电子有限公司 | Dimming control apparatus |
| CN105792415B (en) * | 2016-03-18 | 2018-01-16 | 明纬(广州)电子有限公司 | Light adjusting and controlling device |
| TWI650947B (en) * | 2017-12-22 | 2019-02-11 | 隆達電子股份有限公司 | Filter circuit and control system |
| US10756706B2 (en) | 2017-12-22 | 2020-08-25 | Lextar Electronics Corporation | PWM filter circuit and related control system |
| CN112533320A (en) * | 2019-08-28 | 2021-03-19 | 群光电能科技股份有限公司 | Light emitting diode control device |
| CN112533320B (en) * | 2019-08-28 | 2023-05-12 | 群光电能科技股份有限公司 | LED control device |
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