CN202797873U - Light-emitting diode (LED) short-circuit protection circuit - Google Patents

Light-emitting diode (LED) short-circuit protection circuit Download PDF

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Publication number
CN202797873U
CN202797873U CN 201220494580 CN201220494580U CN202797873U CN 202797873 U CN202797873 U CN 202797873U CN 201220494580 CN201220494580 CN 201220494580 CN 201220494580 U CN201220494580 U CN 201220494580U CN 202797873 U CN202797873 U CN 202797873U
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CN
China
Prior art keywords
circuit
led
short
resistance
voltage
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Expired - Fee Related
Application number
CN 201220494580
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Chinese (zh)
Inventor
魏雄
陈家词
夏银华
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DONGGUAN AOYUAN ELECTRONIC TECHNOLOGY Co Ltd
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DONGGUAN AOYUAN ELECTRONIC TECHNOLOGY Co Ltd
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Priority to CN 201220494580 priority Critical patent/CN202797873U/en
Application granted granted Critical
Publication of CN202797873U publication Critical patent/CN202797873U/en
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Expired - Fee Related legal-status Critical Current

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Abstract

The utility model relates to the field of a light-emitting diode (LED) circuit, in particular to an LED short-circuit protection circuit. The LED short-circuit protection circuit comprises a voltage sampling circuit for collecting voltage at two negative poles of an LED, a comparator circuit for comparing the collected voltage of the negative poles and a short-circuit protection monitoring circuit for controlling an LED power supply according to comparative results, the collecting end of the voltage sampling circuit is connected with two negative pole voltage output ends of the LED, the comparison voltage output end of the voltage sampling circuit is connected with the comparison voltage input end of the comparator circuit, and the control end of the comparator circuit is connected with the input end of the short-circuit protection monitoring circuit. Voltage values of the LED collected by the voltage sampling circuit are input by the comparator circuit, movement of the short-circuit protection monitoring circuit is controlled by the results output by the comparator circuit, and a short-circuit protection function is started if an LED lamp has short circuits.

Description

A kind of LED short-circuit protection circuit
Technical field
The utility model relates to the led circuit field, relates in particular to a kind of LED short-circuit protection circuit.
Background technology
The IC that is used for control LED has in the market abandoned short-circuit protection function because of the restriction of cost and technology, and can there be unsafe factor in product when using.
Summary of the invention
The purpose of this utility model is to overcome shortcoming and defect of the prior art, and a kind of LED short-circuit protection circuit is provided.
To achieve these goals; the utility model adopts following technical scheme: a kind of LED short-circuit protection circuit; comprise for the voltage sampling circuit that gathers two cathode voltages of LED, be used for the comparison circuit of the cathode voltage that relatively gathers and according to the short-circuit protection observation circuit of comparative result control LED power supply; two cathode voltage outputs of the collection terminal of voltage sampling circuit and LED are connected; the comparative voltage output of voltage sampling circuit is connected with the comparative voltage input of comparison circuit, and the control end of comparison circuit is connected with the input of short-circuit protection observation circuit.
Wherein, described voltage sampling circuit comprises capacitor C 1, resistance R 3, R4, R5, R6, R7, R10 and R12; The end of R10, the end of C1 are connected an end and all are connected with constant voltage source Vcc with R7, the other end of R10 is connected with the end of R12, the other end ground connection of R12, the end of the other end of R7, the other end of C1, R3 is connected an end and is connected with R5, the other end of R3 is connected an end and is connected with R4, the other end of R4 is connected the cathode voltage output and is connected with LED, the other end of R5 is connected an end and is connected with R6, and the other end of R6 is connected the cathode voltage output and is connected with LED.
Wherein, described comparison circuit comprises resistance R 8 and R9, diode D1 and D2, capacitor C 2, triode Q2; The end of R8 is connected with constant voltage source Vcc, the other end of R8 is connected with the collector electrode of triode, the positive pole of D1 is connected with the other end of R5, the negative pole of D1, the negative pole of D2 are connected base stage and are connected with Q2, the positive pole of D2 is connected with the other end of R3, the emitter of Q2 is connected with the end of R9, the end of C2 respectively, the other end ground connection of the other end of R9, C2.
Wherein, described short-circuit protection observation circuit comprises control chip and the resistance R 11 that contains the short-circuit protection end, and the end of R11 connects the emitter of Q2, and the other end of R11 connects the short-circuit protection end.
Wherein, described C1 is 104PF/50V electric capacity, and R3, R4, R5 and R6 are the resistance of resistance 75K Ω, and R7, R10 and R12 are the resistance of resistance 10K Ω.
Wherein, described R8 is the resistance of resistance 5.1K Ω, and R9 is the resistance of resistance 10K Ω, and D1 and D2 are the IN4148 diode, and C2 is model 104PF/50V electric capacity, and triode Q2 is model 2N2222 triode.
Wherein, described R11 is the resistance of resistance 1K Ω.
Wherein, described control chip is the LA8303 chip.
The beneficial effects of the utility model are: the utility model comprises for the voltage sampling circuit that gathers two cathode voltages of LED, be used for the comparison circuit of the cathode voltage that relatively gathers and according to the short-circuit protection observation circuit of comparative result control LED power supply, the magnitude of voltage input comparison circuit of the LED that voltage sampling circuit gathers, the action of the output control short-circuit protection observation circuit of comparison circuit output, if short circuit appears in the LED lamp, then start short-circuit protection function; The utility model is realized by simple peripheral circuit, and is with low cost; And rely on diode and triode and realize defencive function, circuit safety and accurate; The utility model has also been avoided the damage of LED short circuit to control chip; Simultaneously, adopt the utility model after, can select the control chip in withstand voltage, must very high situation compare with the withstand voltage of control chip in the prior art, reduced material cost.
Description of drawings
Fig. 1 is circuit diagram of the present utility model.
Fig. 2 is circuit diagram of the present utility model.
Fig. 3 is the circuit diagram of two cathode voltage outputs of LED of the present utility model.
Fig. 1 to Fig. 3 comprises the following drawings mark:
Voltage sampling circuit-1; Comparison circuit-2; Short-circuit protection observation circuit-3.
Embodiment
Below in conjunction with accompanying drawing the utility model is described in detail.
With reference to figure 1; the utility model comprises for the voltage sampling circuit 1 that gathers two cathode voltages of LED, be used for the comparison circuit 2 of the cathode voltage that relatively gathers and according to the short-circuit protection observation circuit 3 of comparative result control LED power supply; two cathode voltage outputs of the collection terminal of voltage sampling circuit 1 and LED are connected; the comparative voltage output of voltage sampling circuit 1 is connected with the comparative voltage input of comparison circuit 2, and the control end of comparison circuit 2 is connected with the input of short-circuit protection observation circuit 3.
With reference to figure 2, voltage sampling circuit 1 comprises capacitor C 1, resistance R 3, R4, R5, R6, R7, R10 and R12; The end of R10, the end of C1 are connected an end and all are connected with constant voltage source Vcc with R7, the other end of R10 is connected with the end of R12, the other end ground connection of R12, the end of the other end of R7, the other end of C1, R3 is connected an end and is connected with R5, the other end of R3 is connected an end and is connected with R4, the other end of R4 is connected the cathode voltage output and is connected (being LED1-) with LED, the other end of R5 is connected an end and is connected with R6, and the other end of R6 is connected cathode voltage output (being LED2-) and is connected with LED.
Comparison circuit 2 comprises resistance R 8 and R9, diode D1 and D2, capacitor C 2, triode Q2; The end of R8 is connected with constant voltage source Vcc, the other end of R8 is connected with the collector electrode of triode, the positive pole of D1 is connected with the other end of R5, the negative pole of D1, the negative pole of D2 are connected base stage and are connected with Q2, the positive pole of D2 is connected with the other end of R3, the emitter of Q2 is connected with the end of R9, the end of C2 respectively, the other end ground connection of the other end of R9, C2.
Short-circuit protection observation circuit 3 comprises control chip and the resistance R 11 that contains the short-circuit protection end, and the end of R11 connects the emitter of Q2, and the other end of R11 connects the short-circuit protection end.
Vcc is the control chip feeder ear of LED power supply, and Vcc is high level.Be LED lamp cathode voltage with reference to figure 2 and 3, LED1-and LED2-, these two point voltages relatively are negative pressure, and the SCP point is the short-circuit protection end of control chip, when voltage is high level, and control chip shutdown.The voltage sampling circuit 1 that comprises resistance R 3, R4, R5 and R6 is sampled to the voltage of LED1-and LED2-respectively, and during normal operation, LED1-and LED2-are negative pressure, at this moment, diode D1, D2 is failure to actuate, triode Q2 base stage no current flows through, the Q2 cut-off, and SCP voltage is low level.When short circuit appears in the LED lamp, LED1-and the meeting of LED2-voltage and ground short circuit, at this moment; R3, R4, R5 and R6 carry out dividing potential drop to Vcc, D1, and the D2 conducting provides electric current for the Q2 base stage; the Q2 conducting, SCP changes high level into by low level, thus control chip shutdown realizes the LED short-circuit protection.
Voltage sampling circuit 1 in the present embodiment, comparison circuit 2 and short-circuit protection observation circuit 3 adopt above-mentioned execution mode, in addition, also can use other components and parts with identical function and other execution modes of connected mode.
Voltage sampling circuit 1 gathers the voltage of LED the first cathode voltage output and LED the second cathode voltage output, and magnitude of voltage inputted comparison circuit 2, comparison circuit 2 if short circuit appears in the LED lamp, then starts short-circuit protection function by the action of comparative result control short-circuit protection observation circuit 3; The utility model is realized short-circuit protection function by simple peripheral circuit, and is with low cost; And rely on diode and triode and realize defencive function, circuit safety and accurate; The utility model has also been avoided the damage of LED short circuit to control chip; Simultaneously, behind employing the utility model, can select withstand voltage moderate control chip, must very high situation compare with the withstand voltage of control chip in the prior art, reduce material cost.
As preferred embodiment: C1 is the electric capacity of 104PF/50V, and R3, R4, R5 and R6 are the resistance that resistance is 75K Ω, and R7, R10 and R12 are the resistance that resistance is 10K Ω.
R8 is that resistance is the resistance of 5.1K Ω, and R9 is that resistance is the resistance of 10K Ω, and D1 and D2 are the IN4148 diode, and C2 is model 104PF/50V electric capacity, and triode Q2 is model 2N2222 triode.R11 is that resistance is the resistance of 1K Ω.Control chip is the LA8303 chip, and control chip also can be other with the chip of SCP function.Certainly, those of ordinary skill in the art for satisfying the actual production demand, according to common practise and limited experiment, can adjust above-mentioned components and parts and parameter value.
Above content only is preferred embodiment of the present utility model, for those of ordinary skill in the art, according to thought of the present utility model, all will change in specific embodiments and applications, this description should not be construed as restriction of the present utility model.

Claims (8)

1. LED short-circuit protection circuit; it is characterized in that: comprise for the voltage sampling circuit that gathers two cathode voltages of LED, be used for the comparison circuit of the cathode voltage that relatively gathers and according to the short-circuit protection observation circuit of comparative result control LED power supply; two cathode voltage outputs of the collection terminal of voltage sampling circuit and LED are connected; the comparative voltage output of voltage sampling circuit is connected with the comparative voltage input of comparison circuit, and the control end of comparison circuit is connected with the input of short-circuit protection observation circuit.
2. a kind of LED short-circuit protection circuit according to claim 1, it is characterized in that: described voltage sampling circuit comprises capacitor C 1, resistance R 3, R4, R5, R6, R7, R10 and R12; The end of R10, the end of C1 are connected an end and all are connected with constant voltage source Vcc with R7, the other end of R10 is connected with the end of R12, the other end ground connection of R12, the end of the other end of R7, the other end of C1, R3 is connected an end and is connected with R5, the other end of R3 is connected an end and is connected with R4, the other end of R4 is connected the cathode voltage output and is connected with LED, the other end of R5 is connected an end and is connected with R6, and the other end of R6 is connected the cathode voltage output and is connected with LED.
3. a kind of LED short-circuit protection circuit according to claim 2, it is characterized in that: described comparison circuit comprises resistance R 8 and R9, diode D1 and D2, capacitor C 2, triode Q2; The end of R8 is connected with constant voltage source Vcc, the other end of R8 is connected with the collector electrode of triode, the positive pole of D1 is connected with the other end of R5, the negative pole of D1, the negative pole of D2 are connected base stage and are connected with Q2, the positive pole of D2 is connected with the other end of R3, the emitter of Q2 is connected with the end of R9, the end of C2 respectively, the other end ground connection of the other end of R9, C2.
4. a kind of LED short-circuit protection circuit according to claim 3; it is characterized in that: described short-circuit protection observation circuit comprises control chip and the resistance R 11 that contains the short-circuit protection end; the end of R11 connects the emitter of Q2, and the other end of R11 connects the short-circuit protection end.
5. a kind of LED short-circuit protection circuit according to claim 2, it is characterized in that: described C1 is 104PF/50V electric capacity, and R3, R4, R5 and R6 are the resistance of resistance 75K Ω, and R7, R10 and R12 are the resistance of resistance 10K Ω.
6. a kind of LED short-circuit protection circuit according to claim 3; it is characterized in that: described R8 is the resistance of resistance 5.1K Ω, and R9 is the resistance of resistance 10K Ω, and D1 and D2 are the IN4148 diode; C2 is model 104PF/50V electric capacity, and triode Q2 is model 2N2222 triode.
7. a kind of LED short-circuit protection circuit according to claim 4, it is characterized in that: described R11 is the resistance of resistance 1K Ω.
8. a kind of LED short-circuit protection circuit according to claim 4, it is characterized in that: described control chip is the LA8303 chip.
CN 201220494580 2012-09-26 2012-09-26 Light-emitting diode (LED) short-circuit protection circuit Expired - Fee Related CN202797873U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 201220494580 CN202797873U (en) 2012-09-26 2012-09-26 Light-emitting diode (LED) short-circuit protection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 201220494580 CN202797873U (en) 2012-09-26 2012-09-26 Light-emitting diode (LED) short-circuit protection circuit

Publications (1)

Publication Number Publication Date
CN202797873U true CN202797873U (en) 2013-03-13

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Application Number Title Priority Date Filing Date
CN 201220494580 Expired - Fee Related CN202797873U (en) 2012-09-26 2012-09-26 Light-emitting diode (LED) short-circuit protection circuit

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016090645A1 (en) * 2014-12-12 2016-06-16 深圳市聚作照明股份有限公司 Driving protection circuit and led switch-mode power supply
CN106953300A (en) * 2017-04-14 2017-07-14 深圳创维-Rgb电子有限公司 A kind of protective circuit of switch power source and display device
CN112498272A (en) * 2020-11-26 2021-03-16 惠州市德赛西威汽车电子股份有限公司 Alarm lamp diagnostic circuit and automobile instrument

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016090645A1 (en) * 2014-12-12 2016-06-16 深圳市聚作照明股份有限公司 Driving protection circuit and led switch-mode power supply
CN106953300A (en) * 2017-04-14 2017-07-14 深圳创维-Rgb电子有限公司 A kind of protective circuit of switch power source and display device
CN112498272A (en) * 2020-11-26 2021-03-16 惠州市德赛西威汽车电子股份有限公司 Alarm lamp diagnostic circuit and automobile instrument

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CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20130313

Termination date: 20150926

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