CN201571238U - LED constant current switch power circuit - Google Patents
LED constant current switch power circuit Download PDFInfo
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- CN201571238U CN201571238U CN 200920294170 CN200920294170U CN201571238U CN 201571238 U CN201571238 U CN 201571238U CN 200920294170 CN200920294170 CN 200920294170 CN 200920294170 U CN200920294170 U CN 200920294170U CN 201571238 U CN201571238 U CN 201571238U
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Abstract
The utility model discloses a LED constant current switch power circuit, characterized in that the LED constant current switch power circuit includes a controllable power supply and a feedback circuit, one output end of the controllable power supply is connected with a LED, the feedback circuit is provided with a thermister R5 adjacent to the LED, and a feedback end of the feedback circuit is connected with the controllable power supply. The obvious beneficial effects are that structure is simple, cost is low, and the LED lamp will be burned due to hyper-high temperature.
Description
Technical field
The utility model belongs to LED power supply and resist technology field, specifically, relates to the constant current switch power circuit of a kind of LED.
Background technology
The LED light fixture has advantages such as energy-saving and environmental protection, long service life, rich color, and the LED lighting technology has been widely used in indoor and outdoor lighting, the many fields of glory setting lamp, and the operational environment of LED lamp is big electric current, low-voltage.Simultaneously, the LED lamp can produce a large amount of heat energy at work, and the LED lamp is easy to because environment or self temperature are too high, thereby influences the useful life of LED lamp, even burns the LED lamp.
The shortcoming of prior art is: can't effectively control LED lamp working temperature, the LED lamp is easy to that Yin Wendu is too high to be burnt.
The utility model content
The purpose of this utility model is to provide a kind of LED constant current switch power circuit, can prolong the useful life of LED lamp, and protection LED lamp can not burnt because of temperature is too high.
For solving above technical problem, the technical solution of the utility model is as follows: a kind of LED constant current switch power circuit, its key is: be provided with controllable electric power and feedback circuit, the output of this controllable electric power is connected with LED, described feedback circuit is provided with thermistor, this thermistor is near described LED, and the feedback end of this feedback circuit connects described controllable electric power.
Described controllable electric power is provided with DC power supply and transformer, first end of the described transformer input of the positive supply termination of this DC power supply primary coil, the anode of second termination, second diode of this input primary coil, connect the positive power source terminal of described DC power supply behind negative electrode string first electric capacity of this second diode, the two ends of this first electric capacity also are connected to first resistance, second end of described input primary coil also is connected with the collector electrode of triode, the grounded emitter of this triode, connect an end of described transformer input secondary coil behind base stage string the 3rd electric capacity of this triode, the other end ground connection of this input secondary coil, connect the positive power source terminal of described DC power supply behind the base stage string pull-up resistor of described triode, the base stage of this triode also connects described feedback circuit;
Described feedback circuit is provided with first diode, the anode of this first diode connects an end of described transformer output winding, the other end ground connection of this transformer output winding, the negative electrode of described first diode connects the anode of LED, ground connection behind negative electrode string the 3rd resistance of this LED, the negative electrode of this LED also connects the reverse input end of comparator, the negative electrode of described first diode connects the front end of the 4th resistance, ground connection behind the rear end string voltage stabilizing didoe of the 4th resistance, the positive input that connects described comparator behind the 8th resistance is also gone here and there in the rear end of the 4th resistance, the base stage of the described triode of output termination of this comparator.
String just has the 4th electric capacity between the positive input of described comparator and the ground.
The base stage of described triode is connected with the negative electrode of the 3rd diode, the plus earth of the 3rd diode.
Ground connection behind the electric capacity is separated in the negative electrode crosstalk of described first diode.
Described feedback circuit also is provided with second triode and the 6th resistance, connect the base stage of second triode behind the anode series thermistor of described LED, ground connection behind base stage string the 6th resistance of this second triode, the collector electrode of this second triode connects the base stage of described triode, the grounded emitter of this second triode.
Described thermistor and described LED fit together.
Transistor collector output switching signal driving transformer primary coil, and be coupled to the transformer secondary coil and draw, again by second resistance, the 3rd electric capacity forms positive feedback and produces self-oscillation, and second resistance string is connected between secondary coil and the 3rd electric capacity.Triode is in switch working state, the turn-on and turn-off time is by the 3rd electric capacity and the decision of second resistance, the base stage of triode is connected with comparator output terminal with second transistor collector respectively again, when second triode or comparator had certain pull-down current, the duty ratio of triode conducting all can reduce.
Thermistor is a negative tempperature coefficient thermistor, when the LED working temperature raises, since and between the thermistor thermal coupling is arranged, and can produce following negative feedback process: the LED temperature ↑, thermistor temp ↑, the thermistor resistance value ↓, the second transistor collector electric current ↑, the minimizing of triode conducting duty ratio ↓, LED power ↓, the LED temperature ↓, thus it is too high to have limited the LED temperature.
When the LED electric current was excessive, pressure drop increases on the 3rd resistance, following negative feedback process can occur: comparator negative input voltage surpassed positive input, comparator output terminal is produced pull-down current, the minimizing of triode conducting duty ratio ↓, the LED electric current ↓, thereby realize constant current.
Comparator positive input voltage equals reference voltage Vref during steady operation, according to the constant current principle as can be known, the 3rd resistance drop is tending towards comparator positive input voltage to earth, and positive input Vref voltage is low more, the 3rd resistance drop is more little, and LED power is also more little.The 8th resistance and the 4th electric capacity are connected into integrating circuit among the figure, when whole system connected power supply, comparator positive input voltage rose with the RC charging curve in time, must just reach rated value through after a while, limit the power when LED powers on, realized soft start.
Beneficial effect: the utility model provides LED constant current switch power circuit a kind of simple in structure, with low cost, and protection LED lamp can not burnt because of temperature is too high.Simultaneously, for LED provides a constant current switch power supply, limited the power when powering on, realized soft start, protection LED can be not too high because of starting resistor, causes damage.
Description of drawings
Fig. 1 is a connection block diagram of the present utility model;
Fig. 2 is the circuit diagram of embodiment 1;
Fig. 3 is the circuit diagram of embodiment 2.
Embodiment
The utility model is described in further detail below in conjunction with drawings and Examples:
Embodiment 1: as shown in Figure 1, the utility model provides a kind of LED constant current switch power circuit, its key is: be provided with controllable electric power and feedback circuit, the output of this controllable electric power is connected with LED, described feedback circuit is provided with thermistor R5, this thermistor R5 is near described LED, and the feedback end of this feedback circuit connects described controllable electric power.
Described controllable electric power is provided with DC power supply and transformer T1, first end of the described transformer T1 input of the positive supply termination of this DC power supply primary coil, the anode of second termination, the second diode D2 of this input primary coil, connect the positive power source terminal of described DC power supply after negative electrode string first capacitor C 1 of this second diode D2, the two ends of this first capacitor C 1 also are connected to first resistance R 1, second end of described input primary coil also is connected with the collector electrode of triode Q1, the grounded emitter of this triode Q1, connect an end of described transformer T1 input secondary coil after base stage string the 3rd capacitor C 3 of this triode Q1, the other end ground connection of this input secondary coil, connect the positive power source terminal of described DC power supply behind the base stage string pull-up resistor R9 of described triode Q1, the base stage of this triode Q1 also connects described feedback circuit;
Described feedback circuit is provided with the first diode D1, the anode of this first diode D1 connects an end of described transformer T1 output winding, the other end ground connection of this transformer T1 output winding, the negative electrode of the described first diode D1 connects the anode of LED, negative electrode string the 3rd resistance R 3 back ground connection of this LED, the negative electrode of this LED also connects the reverse input end of comparator U, the negative electrode of the described first diode D1 connects the front end of the 4th resistance R 4, ground connection behind the rear end string voltage stabilizing didoe D4 of the 4th resistance R 4, the positive input that meets described comparator U after the 8th resistance R 8 is also gone here and there in the rear end of the 4th resistance R 4, the base stage of the described triode Q1 of output termination of this comparator U.
String just has the 4th capacitor C 4 between the positive input of described comparator U and the ground.
The base stage of described triode Q1 is connected with the negative electrode of the 3rd diode D3, the plus earth of the 3rd diode D3.
Capacitor C 2 back ground connection are separated in the negative electrode crosstalk of the described first diode D1.
Described feedback circuit also is provided with the second triode Q2 and the 6th resistance R 6, connect the base stage of the second triode Q2 behind the anode series thermistor R5 of described LED, base stage string the 6th resistance R 6 back ground connection of this second triode Q2, the collector electrode of this second triode Q2 connects the base stage of described triode Q1, the grounded emitter of this second triode Q2.
Described thermistor R5 and described LED fit together.
Its workflow is as follows: triode Q1 collector electrode output switching signal driving transformer T1 primary coil, and be coupled to transformer T1 secondary coil and draw, again by second resistance R 2, the 3rd capacitor C 3 forms positive feedback and produces self-oscillation, and second resistance R 2 is serially connected between secondary coil and the 3rd capacitor C 3.Triode Q1 is in switch working state, the turn-on and turn-off time is by the 3rd capacitor C 3 and 2 decisions of second resistance R, the base stage of triode Q1 is connected with comparator U output with the second triode Q2 collector electrode respectively again, when the second triode Q2 or comparator U had certain pull-down current, the duty ratio of triode Q1 conducting all can reduce.
Thermistor R5 is a negative tempperature coefficient thermistor, when the LED working temperature raises, since and between the thermistor R5 thermal coupling is arranged, and can produce following negative feedback process: the LED temperature ↑, thermistor R5 temperature ↑, thermistor R5 resistance value ↓, the second triode Q2 collector current ↑, the minimizing of triode Q1 conducting duty ratio ↓, LED power ↓, the LED temperature ↓, thus it is too high to have limited the LED temperature.
When the LED electric current was excessive, pressure drop increases on the 3rd resistance R 3, following negative feedback process can occur: comparator U negative input voltage surpassed positive input, comparator U output is produced pull-down current, the minimizing of triode Q1 conducting duty ratio ↓, the LED electric current ↓, thereby realize constant current.
Comparator U positive input voltage equals reference voltage Vref during steady operation, according to the constant current principle as can be known, 3 pressure drops of the 3rd resistance R are tending towards comparator U positive input voltage to earth, and positive input Vref voltage is low more, 3 pressure drops of the 3rd resistance R are more little, and LED power is also more little.The 8th resistance R 8 and the 4th capacitor C 4 are connected into integrating circuit among the figure, when whole system connected power supply, comparator U positive input voltage rose with the RC charging curve in time, must just reach rated value through after a while, limit the power when LED powers on, realized soft start.
In the utility model, not only be confined to the expressed circuit structure of embodiment 1, the mode of building of controllable electric power and feedback circuit is a lot, and all among the utility model protection range, as embodiment 2, the structure of present embodiment 2 is as follows:
The positive power source terminal of DC power supply BT1 is connected the emitter of PNP triode Q, and the collector electrode of this PNP triode Q and the negative power end of described DC power supply BT1 are powered to LED; The anode of LED connects the collector electrode of described PNP triode Q1, and negative electrode connects the negative power end of DC power supply BT1.
DC power supply BT1 and PNP triode Q form controllable electric power.
Between the base stage of described PNP triode Q and the collector electrode and be connected to resistance R, between the base stage of described PNP triode Q and the emitter and be connected to thermistor R5, this thermistor R5 is near described LED.
Resistance R and thermistor R5 form feedback circuit.
Its workflow is as follows:
LED lamp D1 temperature rising → thermistor R5 resistance value decline → PNP triode Q1 base voltage rising → PNP triode Q1 collector current decline → LED lamp D1 power decline → LED lamp D1 temperature descends, thereby has protected the LED lamp D1 temperature can be not too high.
Claims (7)
1. LED constant current switch power circuit, it is characterized in that: be provided with controllable electric power and feedback circuit, the output of this controllable electric power is connected with LED, described feedback circuit is provided with thermistor (R5), this thermistor (R5) is near described LED, and the feedback end of this feedback circuit connects described controllable electric power.
2. LED constant current switch power circuit according to claim 1, it is characterized in that: described controllable electric power is provided with DC power supply and transformer (T1), first end of the described transformer of positive supply termination (T1) the input primary coil of this DC power supply, the anode of second termination, second diode (D2) of this input primary coil, connect the positive power source terminal of described DC power supply behind negative electrode string first electric capacity (C1) of this second diode (D2), the two ends of this first electric capacity (C1) also are connected to first resistance (R1), second end of described input primary coil also is connected with the collector electrode of triode (Q1), the grounded emitter of this triode (Q1), connect an end of described transformer (T1) input secondary coil behind base stage string the 3rd electric capacity (C3) of this triode (Q1), the other end ground connection of this input secondary coil, connect the positive power source terminal of described DC power supply behind the base stage string pull-up resistor (R9) of described triode (Q1), the base stage of this triode (Q1) also connects described feedback circuit;
Described feedback circuit is provided with first diode (D1), the anode of this first diode (D1) connects an end of described transformer (T1) output winding, the other end ground connection of this transformer (T1) output winding, the negative electrode of described first diode (D1) connects the anode of LED, negative electrode string the 3rd resistance (R3) the back ground connection of this LED, the negative electrode of this LED also connects the reverse input end of comparator (U), the negative electrode of described first diode (D1) connects the front end of the 4th resistance (R4), rear end string voltage stabilizing didoe (D4) the back ground connection of the 4th resistance (R4), the positive input that meets described comparator (U) behind the 8th resistance (R8) is also gone here and there in the rear end of the 4th resistance (R4), the base stage of the described triode of output termination (Q1) of this comparator (U).
3. LED constant current switch power circuit according to claim 2 is characterized in that: string just has the 4th electric capacity (C4) between the positive input of described comparator (U) and the ground.
4. LED constant current switch power circuit according to claim 2 is characterized in that: the base stage of described triode (Q1) is connected with the negative electrode of the 3rd diode (D3), the plus earth of the 3rd diode (D3).
5. LED constant current switch power circuit according to claim 2 is characterized in that: electric capacity (C2) back ground connection is separated in the negative electrode crosstalk of described first diode (D1).
6. LED constant current switch power circuit according to claim 2, it is characterized in that: described feedback circuit also is provided with second triode (Q2) and the 6th resistance (R6), connect the base stage of second triode (Q2) behind the anode series thermistor (R5) of described LED, base stage string the 6th resistance (R6) the back ground connection of this second triode (Q2), the collector electrode of this second triode (Q2) connects the base stage of described triode (Q1), the grounded emitter of this second triode (Q2).
7. LED constant current switch power circuit according to claim 1 is characterized in that: described thermistor (R5) fits together with described LED.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200920294170 CN201571238U (en) | 2009-12-28 | 2009-12-28 | LED constant current switch power circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200920294170 CN201571238U (en) | 2009-12-28 | 2009-12-28 | LED constant current switch power circuit |
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| Publication Number | Publication Date |
|---|---|
| CN201571238U true CN201571238U (en) | 2010-09-01 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200920294170 Expired - Fee Related CN201571238U (en) | 2009-12-28 | 2009-12-28 | LED constant current switch power circuit |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101968174A (en) * | 2010-10-26 | 2011-02-09 | 江苏奥雷光电有限公司 | LED assembly for lighting |
| CN101977469A (en) * | 2010-11-11 | 2011-02-16 | 重庆三弓科技发展有限公司 | Adjustable LED drive power supply |
| CN102970798A (en) * | 2012-11-15 | 2013-03-13 | 深圳和而泰照明科技有限公司 | Drive circuit and LED (Light-Emitting Diode) illuminating device |
| CN103025014A (en) * | 2012-12-12 | 2013-04-03 | 宁波市镇海华泰电器厂 | Light-emitting diode (LED) lamp driving power supply with functions of lightning resistance and automatic temperature control |
| CN103220838A (en) * | 2013-04-23 | 2013-07-24 | 广州市隆都电子有限公司 | Light-emitting diode (LED) ballast driving circuit |
| CN112783254A (en) * | 2020-12-23 | 2021-05-11 | 南京交通职业技术学院 | Auxiliary voltage source capable of automatically adjusting output and suitable for building safety |
-
2009
- 2009-12-28 CN CN 200920294170 patent/CN201571238U/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101968174A (en) * | 2010-10-26 | 2011-02-09 | 江苏奥雷光电有限公司 | LED assembly for lighting |
| CN101977469A (en) * | 2010-11-11 | 2011-02-16 | 重庆三弓科技发展有限公司 | Adjustable LED drive power supply |
| CN101977469B (en) * | 2010-11-11 | 2013-07-10 | 重庆三弓科技发展有限公司 | Adjustable LED drive power supply |
| CN102970798A (en) * | 2012-11-15 | 2013-03-13 | 深圳和而泰照明科技有限公司 | Drive circuit and LED (Light-Emitting Diode) illuminating device |
| CN102970798B (en) * | 2012-11-15 | 2015-03-11 | 深圳和而泰照明科技有限公司 | Drive circuit and LED (Light-Emitting Diode) illuminating device |
| CN103025014A (en) * | 2012-12-12 | 2013-04-03 | 宁波市镇海华泰电器厂 | Light-emitting diode (LED) lamp driving power supply with functions of lightning resistance and automatic temperature control |
| CN103025014B (en) * | 2012-12-12 | 2014-12-10 | 宁波市镇海华泰电器厂 | Light-emitting diode (LED) lamp driving power supply with functions of lightning resistance and automatic temperature control |
| CN103220838A (en) * | 2013-04-23 | 2013-07-24 | 广州市隆都电子有限公司 | Light-emitting diode (LED) ballast driving circuit |
| CN103220838B (en) * | 2013-04-23 | 2016-03-02 | 陈经湛 | LED ballast driven circuit |
| CN112783254A (en) * | 2020-12-23 | 2021-05-11 | 南京交通职业技术学院 | Auxiliary voltage source capable of automatically adjusting output and suitable for building safety |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 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: 20100901 Termination date: 20141228 |
|
| EXPY | Termination of patent right or utility model |