CN105472811A - Overheat protection circuit for LED - Google Patents
Overheat protection circuit for LED Download PDFInfo
- Publication number
- CN105472811A CN105472811A CN201510954257.5A CN201510954257A CN105472811A CN 105472811 A CN105472811 A CN 105472811A CN 201510954257 A CN201510954257 A CN 201510954257A CN 105472811 A CN105472811 A CN 105472811A
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- CN
- China
- Prior art keywords
- triode
- resistance
- led
- control circuit
- protection circuit
- Prior art date
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Classifications
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/40—Details of LED load circuits
- H05B45/44—Details of LED load circuits with an active control inside an LED matrix
-
- 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]
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The invention relates to an overheat protection circuit for an LED. The circuit comprises a temperature detection circuit, a temperature control circuit and a constant current control circuit. The constant current control circuit comprises triodes Q1 and Q2, resistors R4, R5 and R6 and a capacitor C2. The emitting electrode of the triode Q1 is grounded through the resistor R6; the collecting electrode of the triode Q1 is connected with an input end of the LED lamp and is connected with the temperature control circuit through the resistor R4; the base electrode of the triode Q1 is grounded through the capacitor C2; the base electrode of the triode Q2 is connected with the emitting electrode of the triode Q1; the emitting electrode of the triode Q2 is grounded; and the collecting electrode of the triode Q2 is connected with the base electrode of the triode Q1 through the resistor R5. The overheat protection circuit for an LED is simple and safe and reliable, and not only the production cost can be effectively lowered, but also the accuracy of a thermal protection circuit of the LED lamp can be improved, so that the LED lamp is effectively protected.
Description
Technical field
The present invention relates to LED technology field, be specifically related to a kind of LED overheating protection circuit.
Background technology
LED is as new type light source, and it has energy-saving and environmental protection, efficiently feature, and technology is ripe and be applied to every field, and LED is widely used as lighting source.LED is a kind of current mode luminescent device; very responsive to the electric current flowing through self; require relative also very harsh, but LED is as point-source of light, its volume is very little; the heat sent during work is more concentrated; and the life cycle of temperature too high meeting serious curtailment LED, so the working life in order to ensure LED, need to add LED overtemperature protection in LED drive circuit; effectively protect when LED is overheated, prevent temperature too high and damage LED.
Current overheating protection circuit generally adopts and add chip overheating protection in LED constant current drives; indirectly reflect the working temperature of LED; it adopts integrated circuit; have circuit simple, use the advantages such as flexible; but it often can not reflect the working temperature of LED truly; so its accuracy is not high, effective overtemperature protection can not be provided for LED.
Summary of the invention
The object of the present invention is to provide a kind of accuracy high and the LED overheating protection circuit of overtemperature protection can be effectively provided.
For achieving the above object, present invention employs following technical scheme: comprise temperature sensing circuit, temperature-control circuit and constant-current control circuit, described constant-current control circuit comprises triode Q1, Q2, resistance R4, R5, R6 and electric capacity C2, the emitter of described triode Q1 is through resistance R6 ground connection, its collector electrode is connected with the input of LED, and be connected with temperature-control circuit through resistance R4, the base stage of triode Q1 is through electric capacity C2 ground connection, the base stage of described triode Q2 is connected with the emitter of triode Q1, its grounded emitter, its collector electrode is connected with the base stage of triode Q1 through resistance R5.
Described temperature-control circuit comprises resistance R1, R2, R3 and accurate adjustable voltage stabilizer N1, one end of described resistance R1 is connected with power supply, its other end is through resistance R2 ground connection, the plus earth of described accurate adjustable voltage stabilizer N1, its negative electrode is connected with resistance R4 with the base stage of triode Q1 respectively through resistance R3, and the reference edge of accurate adjustable voltage stabilizer N1 is connected to the Nodes between resistance R1 and resistance R2.
Described temperature sensing circuit is made up of thermistor R1, and described thermistor R1 is connected in parallel on the two ends of resistance R2.
The model of described accurate adjustable voltage stabilizer N1 is LM431.
As shown from the above technical solution, LED overheating protection circuit of the present invention, safe and reliable, circuit is simple, not only effectively can reduce production cost, and this overheating protection circuit accuracy high, available protecting can be provided for LED lamp.
Accompanying drawing explanation
Fig. 1 is circuit diagram of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the present invention will be further described:
As shown in Figure 1; the LED overheating protection circuit of the present embodiment; comprise temperature sensing circuit, temperature-control circuit and constant-current control circuit; constant-current control circuit comprises triode Q1, Q2; resistance R4, R5, R6 and electric capacity C2; the emitter of triode Q1 is through resistance R6 ground connection; its collector electrode is connected with the input of LED; and be connected with temperature-control circuit through resistance R4; the base stage of triode Q1 is through electric capacity C2 ground connection; the base stage of triode Q2 is connected with the emitter of triode Q1, its grounded emitter, and its collector electrode is connected with the base stage of triode Q1 through resistance R5.
This temperature-control circuit comprises resistance R1, R2, R3 and accurate adjustable voltage stabilizer N1, one end of resistance R1 is connected with power supply, its other end is through resistance R2 ground connection, the plus earth of accurate adjustable voltage stabilizer N1, its negative electrode is connected with resistance R4 with the base stage of triode Q1 respectively through resistance R3, and the reference edge of accurate adjustable voltage stabilizer N1 is connected to the Nodes between resistance R1 and resistance R2.In the present embodiment, temperature sensing circuit is made up of thermistor R1, and thermistor R1 is connected in parallel on the two ends of resistance R2.The model of accurate adjustable voltage stabilizer N1 is LM431.
Operation principle: when LED normally works, by the 4th resistance R4 to triode Q1 base stage operating current, triode Q1 conducting, LED is started working, and LED is by resistance R6, now electric current is set by triode Q2 conducting voltage, and this conducting voltage is the base voltage of triode Q2.When the electric current of LED increases, namely triode Q2 base current strengthens, pressure drop between triode Q2 collector electrode and emitter reduces, collector current increases, thus make the base bleeder current of triode Q1 that its electric current is reduced, the collector current of triode Q1 declines, and makes electric current drop to setting current work, thus keeps LED stably to work.When LED temperature is too high; thermistor resistance raises; accurate adjustable voltage stabilizer N1 raises with reference to pole tension; when reaching operating current, accurate adjustable voltage stabilizer N1 starts working, and shunts the base current of triode Q1; the conducting degree of triode Q1 is declined; LED current reduces, and heat declines, thus serves overheat protector effect.
Above-described embodiment is only be described the preferred embodiment of the present invention; not scope of the present invention is limited; under not departing from the present invention and designing the prerequisite of spirit; the various distortion that those of ordinary skill in the art make technical scheme of the present invention and improvement, all should fall in protection range that claims of the present invention determines.
Claims (4)
1. a LED overheating protection circuit, comprise temperature sensing circuit, temperature-control circuit and constant-current control circuit, it is characterized in that: described constant-current control circuit comprises triode Q1, Q2, resistance R4, R5, R6 and electric capacity C2, the emitter of described triode Q1 is through resistance R6 ground connection, its collector electrode is connected with the input of LED, and be connected with temperature-control circuit through resistance R4, the base stage of triode Q1 is through electric capacity C2 ground connection, the base stage of described triode Q2 is connected with the emitter of triode Q1, its grounded emitter, its collector electrode is connected with the base stage of triode Q1 through resistance R5.
2. LED overheating protection circuit according to claim 1; it is characterized in that: described temperature-control circuit comprises resistance R1, R2, R3 and accurate adjustable voltage stabilizer N1; one end of described resistance R1 is connected with power supply; its other end is through resistance R2 ground connection; the plus earth of described accurate adjustable voltage stabilizer N1; its negative electrode is connected with resistance R4 with the base stage of triode Q1 respectively through resistance R3, and the reference edge of accurate adjustable voltage stabilizer N1 is connected to the Nodes between resistance R1 and resistance R2.
3. LED overheating protection circuit according to claim 2, it is characterized in that: described temperature sensing circuit is made up of thermistor R1, described thermistor R1 is connected in parallel on the two ends of resistance R2.
4. LED overheating protection circuit according to claim 2, is characterized in that: the model of described accurate adjustable voltage stabilizer N1 is LM431.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510954257.5A CN105472811A (en) | 2015-12-20 | 2015-12-20 | Overheat protection circuit for LED |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510954257.5A CN105472811A (en) | 2015-12-20 | 2015-12-20 | Overheat protection circuit for LED |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105472811A true CN105472811A (en) | 2016-04-06 |
Family
ID=55609947
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510954257.5A Pending CN105472811A (en) | 2015-12-20 | 2015-12-20 | Overheat protection circuit for LED |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105472811A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202276510U (en) * | 2011-09-23 | 2012-06-13 | 广州莱迪光电股份有限公司 | LED (light-emitting diode) lamp overheat protection circuit |
| CN103001177A (en) * | 2011-09-19 | 2013-03-27 | 海洋王（东莞）照明科技有限公司 | LED lamp and overheat protecting circuit thereof |
| CN203261005U (en) * | 2013-04-22 | 2013-10-30 | 深圳创维－Rgb电子有限公司 | LED constant-current over-temperature protection circuit and LED lamp |
-
2015
- 2015-12-20 CN CN201510954257.5A patent/CN105472811A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103001177A (en) * | 2011-09-19 | 2013-03-27 | 海洋王（东莞）照明科技有限公司 | LED lamp and overheat protecting circuit thereof |
| CN202276510U (en) * | 2011-09-23 | 2012-06-13 | 广州莱迪光电股份有限公司 | LED (light-emitting diode) lamp overheat protection circuit |
| CN203261005U (en) * | 2013-04-22 | 2013-10-30 | 深圳创维－Rgb电子有限公司 | LED constant-current over-temperature protection circuit and LED lamp |
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|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20160406 |