CN202276510U - LED (light-emitting diode) lamp overheat protection circuit - Google Patents
LED (light-emitting diode) lamp overheat protection circuit Download PDFInfo
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- CN202276510U CN202276510U CN2011203600589U CN201120360058U CN202276510U CN 202276510 U CN202276510 U CN 202276510U CN 2011203600589 U CN2011203600589 U CN 2011203600589U CN 201120360058 U CN201120360058 U CN 201120360058U CN 202276510 U CN202276510 U CN 202276510U
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Abstract
The utility model discloses an LED lamp overheat protection circuit, which comprises a photoelectric coupler and a voltage division circuit, wherein the photoelectric coupler can drive a pulse width modulation control chip to get into a protected state, the voltage division circuit is connected with a direct-current power supply, and is connected with a light-emitting diode in the photoelectric coupler through a transistor circuit, and a voltage regulation circuit for stabilizing the output voltage of the voltage division circuit is connected in parallel with the voltage division circuit. Because the voltage regulation circuit is connected in parallel with the voltage division circuit, the defect that the precision of the ordinary overheat protection circuit can be easily affected by the fluctuation of input voltage is overcome, thus the misoperation of overheat protection is reduced, and the stability of overheat protection is guaranteed. The LED lamp overheat protection circuit can be widely applied to the field of LED illumination.
Description
Technical field
The utility model relates to LED lamp lighting field, especially a kind of LED light fixture overheating protection circuit.
Background technology
At present, high light efficiency, low light decay, high-power LED (Light Emitting Diode, light-emitting diode) have been widely used in many lighting fields such as street lamp, bulkhead lamp capable, Tunnel Lamp, shot-light, fluorescent lamp, receive the consistent favorable comment of industry deeply.But the heat dissipation problem of LED light fixture is to influence the LED light fixture primary factor in useful life.
Fig. 1 has provided traditional LED light fixture aluminium base overheating protection circuit; Negative tempperature coefficient thermistor RT1 and resistance R 3 constitute a bleeder circuit; Through setting the reasonable resistance of thermistor RT1 and resistance R 3; Make when operate as normal, the voltage of triode Q2 base stage Vb (being the bias voltage of triode conducting) is less than 0.7V; When LED light fixture aluminium base temperature during greater than set point, thermistor RT1 resistance diminishes, and reaches 0.7 volt of triode conducting voltage thereby Vb voltage is raise; Triode is led the logical magnifying state that gets into of Q2; The interior light emitting diodes of photoelectrical coupler U2 is started working, and impels the elementary phototriode conducting of photoelectrical coupler U2, thereby drags down the feedback pin FB voltage of PWM IC gradually; Getting into guard mode until PWM IC quits work; The LED driving power stops output, has prevented that LED lamp pearl from working on and has caused the aluminium base temperature increasingly high, has influenced the life-span of LED.
There is following shortcoming in existing overheating protection circuit:
1, low precision; When the operating voltage instability of this protective circuit perhaps fluctuates, can influence the voltage of transistor base Vb, thereby cause misoperation, protect temperature just to get into guard mode such as reaching to set, perhaps reached the protection temperature spot of setting and but also do not protected.Make LED light fixture cisco unity malfunction.
2, realize that protection speed is slow; When the aluminium base temperature is too high when making the conducting of Vb rising triode; Just get into magnifying state; The electric current of collector electrode is along with temperature raises and increase gradually gradually; The electric current of photoelectrical coupler can not reach maximum fast, and the PWM IC of primary side can not get into guard mode immediately, stops output current.So the overtemperature protection of traditional circuit has hysteresis quality, can not in time protect.
The utility model content
The technical problem that the utility model will solve is: provide a kind of and not disturbed by mains fluctuations, the LED light fixture overheating protection circuit that the protection action is stable.
In order to solve the problems of the technologies described above, the technical scheme that the utility model adopted is:
A kind of LED light fixture overheating protection circuit; Comprise that one drives the photoelectrical coupler that the pulse width modulation controlled chip gets into guard mode; Also comprise the bleeder circuit that is connected with DC power supply; Said bleeder circuit is connected with the interior light-emitting diode of photoelectrical coupler through transistor circuit, is parallel with the voltage stabilizing circuit that makes its output voltage stabilization on the said bleeder circuit.
Further as preferred embodiment; Said bleeder circuit comprises current-limiting resistance, thermistor, the divider resistance of series connection successively; Said voltage stabilizing circuit constitutes the shunt circuit with thermistor of connecting and divider resistance, and the output point that the tie point of said thermistor and divider resistance constitutes bleeder circuit is connected with transistor circuit.
Further as preferred embodiment, said voltage stabilizing circuit is a voltage stabilizing didoe.
Further as preferred embodiment; Said transistor circuit comprises a positive-negative-positive triode and a NPN type triode; The emitter of said positive-negative-positive triode is connected with the interior light-emitting diode of photoelectrical coupler; The base stage of said positive-negative-positive triode is connected with the collector electrode of said NPN type triode, and the base stage of the collector electrode of said positive-negative-positive triode and NPN type triode is connected with the output point of bleeder circuit together.
The beneficial effect of the utility model is: the utility model overheating protection circuit; Through a parallelly connected voltage stabilizing circuit on bleeder circuit; Having overcome general overheating protection circuit receives input voltage fluctuation to influence the drawback of precision easily; Reduce the misoperation of overtemperature protection, guaranteed the stability of overtemperature protection.
Further; The utility model overheating protection circuit improves transistor circuit; Increased a positive-negative-positive triode, be connected with the positive feedback of original NPN type triode, moment the conducting state that can reach capacity; Thereby realized the quick conducting of photoelectrical coupler interior light emitting diodes, responded the overtemperature protection of LED light fixture fast.
Description of drawings
Be described further below in conjunction with the embodiment of accompanying drawing the utility model:
Fig. 1 is the circuit theory diagrams of existing overheating protection circuit;
Fig. 2 is the theory diagram of the utility model overheating protection circuit;
Fig. 3 is the circuit theory diagrams of the utility model overheating protection circuit.
Embodiment
With reference to Fig. 2; A kind of LED light fixture overheating protection circuit; Comprise that one drives the photoelectrical coupler that the pulse width modulation controlled chip gets into guard mode; Also comprise the bleeder circuit that is connected with DC power supply, said bleeder circuit is connected with the interior light-emitting diode of photoelectrical coupler through transistor circuit, is parallel with the voltage stabilizing circuit that makes its output voltage stabilization on the said bleeder circuit.
With reference to Fig. 3; Said bleeder circuit comprises current-limiting resistance R2, thermistor RT1, the divider resistance R3 of series connection successively; Voltage stabilizing didoe TL431 constitutes the shunt circuit with thermistor RT1 that connects and divider resistance R3; Current-limiting resistance R2 and voltage stabilizing didoe TL431 constitute the voltage stabilizing circuit of a 2.5V, and the output point that the tie point of said thermistor RT1 and divider resistance R3 constitutes bleeder circuit is connected with transistor circuit.
Further as preferred embodiment; Said transistor circuit comprises a positive-negative-positive triode Q1 and a NPN type triode Q2; The emitter of said positive-negative-positive triode Q1 is connected with the interior light-emitting diode of photoelectrical coupler U2; The base stage of said positive-negative-positive triode Q1 is connected with the collector electrode of said NPN type triode Q2, and the collector electrode of said positive-negative-positive triode Q1 is connected with the output point of bleeder circuit with the base stage of NPN type triode Q2 together.
In concrete the application; Through setting the suitable resistance of thermistor RT1 and divider resistance R3, make Vb holds when normal temperature work voltage less than 0.7V (bias voltage of NPN type triode Q2 conducting), thermistor RT1 is fixed on the aluminium base that LED lamp pearl belongs to; When LED light fixture aluminium base temperature during greater than set point; Thermistor RT1 resistance diminishes, and reaches 0.7 volt of triode conducting voltage thereby Vb voltage is raise, and the triode conducting gets into magnifying state.
The method that connects of positive-negative-positive triode Q1 and NPN type triode Q2 forms a positive feedback, has auto-lock function, is lower than 0.7V even Vb voltage drops to, and still can keep the saturation conduction state, and operation principle is similar to controllable silicon (thyristor).At NPN type triode Q2, during positive-negative-positive triode Q1 conducting just, because the effect of positive feedback; Positive-negative-positive triode Q1, NPN type triode Q2 get into the saturation conduction state rapidly; Make photoelectrical coupler U2 optocoupler inner light-emitting diode moment reach maximum current output, the phototriode of primary side is saturation conduction rapidly also, drags down the FB of PWM IC (feedback pin) voltage less than shutoff voltage; Thereby forbid PWM IC work; The secondary output current that stops, LED lamp pearl quits work, thereby has realized overheat protective function.
In the present embodiment, owing to the voltage of the base stage Vb that has guaranteed NPN type triode Q2 through current-limiting resistance and voltage stabilizing didoe TL431 is stable, guarantee not receive the influence of external voltage fluctuations; Simultaneously,, constitute positive feedback, accelerated to realize the response speed of overtemperature protection with NPN type triode Q2 through increasing positive-negative-positive triode Q1.
More than be that preferable enforcement to the utility model specifies; But the utility model is created and is not limited to said embodiment; Those of ordinary skill in the art make all equivalent variations or replacement under the prerequisite of the utility model spirit, also can doing, and distortion that these are equal to or replacement all are included in the application's claim institute restricted portion.
Claims (4)
1. LED light fixture overheating protection circuit; Comprise that one drives the photoelectrical coupler that the pulse width modulation controlled chip gets into guard mode; Also comprise the bleeder circuit that is connected with DC power supply; Said bleeder circuit is connected with the interior light-emitting diode of photoelectrical coupler through transistor circuit, it is characterized in that: be parallel with the voltage stabilizing circuit that makes its output voltage stabilization on the said bleeder circuit.
2. a kind of LED light fixture overheating protection circuit according to claim 1 is characterized in that:
Said bleeder circuit comprises current-limiting resistance, thermistor, the divider resistance of series connection successively; Said voltage stabilizing circuit constitutes the shunt circuit with thermistor of connecting and divider resistance, and the output point that the tie point of said thermistor and divider resistance constitutes bleeder circuit is connected with transistor circuit.
3. a kind of LED light fixture overheating protection circuit according to claim 2, it is characterized in that: said voltage stabilizing circuit is a voltage stabilizing didoe.
4. according to each described a kind of LED light fixture overheating protection circuit of claim 1 to 3; It is characterized in that: said transistor circuit comprises a positive-negative-positive triode and a NPN type triode; The emitter of said positive-negative-positive triode is connected with the interior light-emitting diode of photoelectrical coupler; The base stage of said positive-negative-positive triode is connected with the collector electrode of said NPN type triode, and the base stage of the collector electrode of said positive-negative-positive triode and NPN type triode is connected with the output point of bleeder circuit together.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203600589U CN202276510U (en) | 2011-09-23 | 2011-09-23 | LED (light-emitting diode) lamp overheat protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203600589U CN202276510U (en) | 2011-09-23 | 2011-09-23 | LED (light-emitting diode) lamp overheat protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN202276510U true CN202276510U (en) | 2012-06-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011203600589U Expired - Fee Related CN202276510U (en) | 2011-09-23 | 2011-09-23 | LED (light-emitting diode) lamp overheat protection circuit |
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| CN (1) | CN202276510U (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102751700A (en) * | 2012-06-28 | 2012-10-24 | 惠州市德赛视听科技有限公司 | Over-temperature protection circuit |
| CN105050295A (en) * | 2015-08-28 | 2015-11-11 | 深圳市志和兴业电子有限公司 | Over-temperature protection circuit of light-emitting diode (LED) drive power supply |
| CN105472811A (en) * | 2015-12-20 | 2016-04-06 | 合肥艾斯克光电科技有限责任公司 | Overheat protection circuit for LED |
| CN105703611A (en) * | 2016-03-11 | 2016-06-22 | 深圳市华星光电技术有限公司 | Voltage feedback circuit of flyback switching power supply and flyback switching power supply |
| TWI573958B (en) * | 2014-07-22 | 2017-03-11 | 玉晶光電股份有限公司 | Lamp with an overheating protection mechanism |
| CN109410883A (en) * | 2018-12-27 | 2019-03-01 | 惠科股份有限公司 | A kind of booster circuit of display panel, boost control method and display device |
| CN110828397A (en) * | 2019-10-28 | 2020-02-21 | 科华恒盛股份有限公司 | Chip heat dissipation auxiliary circuit and data processing chip |
| CN113964786A (en) * | 2021-07-23 | 2022-01-21 | 南京华士电子科技有限公司 | Long-life output circuit capable of monitoring output current and forcibly turning off after overcurrent |
-
2011
- 2011-09-23 CN CN2011203600589U patent/CN202276510U/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102751700A (en) * | 2012-06-28 | 2012-10-24 | 惠州市德赛视听科技有限公司 | Over-temperature protection circuit |
| TWI573958B (en) * | 2014-07-22 | 2017-03-11 | 玉晶光電股份有限公司 | Lamp with an overheating protection mechanism |
| CN105050295A (en) * | 2015-08-28 | 2015-11-11 | 深圳市志和兴业电子有限公司 | Over-temperature protection circuit of light-emitting diode (LED) drive power supply |
| CN105472811A (en) * | 2015-12-20 | 2016-04-06 | 合肥艾斯克光电科技有限责任公司 | Overheat protection circuit for LED |
| CN105703611A (en) * | 2016-03-11 | 2016-06-22 | 深圳市华星光电技术有限公司 | Voltage feedback circuit of flyback switching power supply and flyback switching power supply |
| CN109410883A (en) * | 2018-12-27 | 2019-03-01 | 惠科股份有限公司 | A kind of booster circuit of display panel, boost control method and display device |
| CN110828397A (en) * | 2019-10-28 | 2020-02-21 | 科华恒盛股份有限公司 | Chip heat dissipation auxiliary circuit and data processing chip |
| CN110828397B (en) * | 2019-10-28 | 2023-01-10 | 科华数据股份有限公司 | Chip heat dissipation auxiliary circuit and data processing chip |
| CN113964786A (en) * | 2021-07-23 | 2022-01-21 | 南京华士电子科技有限公司 | Long-life output circuit capable of monitoring output current and forcibly turning off after overcurrent |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120613 Termination date: 20140923 |
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| EXPY | Termination of patent right or utility model |