CN201571237U - LED overheating protection circuit - Google Patents
LED overheating protection circuit Download PDFInfo
- Publication number
- CN201571237U CN201571237U CN 200920294169 CN200920294169U CN201571237U CN 201571237 U CN201571237 U CN 201571237U CN 200920294169 CN200920294169 CN 200920294169 CN 200920294169 U CN200920294169 U CN 200920294169U CN 201571237 U CN201571237 U CN 201571237U
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- CN
- China
- Prior art keywords
- power supply
- pnp triode
- led
- led lamp
- thermistor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model discloses an LED overheating protection circuit which comprises a direct-current power supply BT1 and is characterized in that a positive power supply end of the direct-current power supply BT1 is connected with an emitting electrode of a PNP triode Q1, and a collector electrode of the PNP triode Q1 and a negative power supply end of the direct-current power supply BT1 are used for supplying power for a load; a resistance R1 is connected between a base electrode and the collector electrode of the PNP triode Q1 in parallel; a thermistor R2 is connected between the base electrode and the emitting electrode of the PNP triode Q1 in parallel; and the thermistor R2 is close to the load. The LED overheating protection circuit has the advantages of having simple structure and low cost, and protecting an LED lamp from being burnt out due to overhigh temperature.
Description
Technical field
The utility model belongs to LED power supply and resist technology field, specifically, relates to the overheating protection 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 overheating protection 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 overheating protection circuit, comprise DC power supply, its key is: the positive power source terminal of this DC power supply is connected the emitter of PNP triode, and the collector electrode of this PNP triode and the negative power end of described DC power supply power to the load;
Between the base stage of described PNP triode and the collector electrode and be connected to resistance, between the base stage of described PNP triode and the emitter and be connected to thermistor, this thermistor is near described load.
Described load is the LED lamp, and the anode of this LED lamp connects the collector electrode of described PNP triode, and the negative electrode of this LED lamp connects the negative power end of described DC power supply.
Thermistor is a negative tempperature coefficient thermistor, and critical temperature Tc is the work ceiling temperature of LED.LED lamp and thermistor mechanically link together, and are used to detect the temperature of LED lamp.
When the LED light temperature was low, the thermistor resistance value was very big, and the PNP triode produces the bias current conducting by resistance,
After detecting the LED light temperature and reaching certain working temperature, thermistor diminishes with the last reduction resistance value of temperature, and the LED lamp is started working, when the LED light temperature near critical temperature Tc, it is as follows to go out negative feedback process:
LED light temperature rising → thermistor resistance value decline → PNP transistor base voltage rising → PNP transistor collector electric current decline → LED lamp power decline → LED light temperature descends, thereby has protected the LED light temperature can be not too high.
Beneficial effect: the utility model provides LED overheating protection circuit a kind of simple in structure, with low cost, and protection LED lamp can not burnt because of temperature is too high.
Description of drawings
Fig. 1 is a circuit diagram of the present utility model.
Embodiment
The utility model is described in further detail below in conjunction with drawings and Examples:
As shown in Figure 1, the utility model provides a kind of LED overheating protection circuit, comprise DC power supply, the positive power source terminal of this DC power supply BT1 is connected the emitter of PNP triode Q1, and the collector electrode of this PNP triode Q1 and the negative power end of described DC power supply BT1 power to the load;
Between the base stage of described PNP triode Q1 and the collector electrode and be connected to resistance R 1, between the base stage of described PNP triode Q1 and the emitter and be connected to thermistor R2, this thermistor R2 is near described load.
Described load is LED lamp D1, and the anode of this LED lamp D1 connects the collector electrode of described PNP triode Q1, and the negative electrode of this LED lamp D1 connects the negative power end of described DC power supply BT1.
Thermistor R2 is a negative tempperature coefficient thermistor, and critical temperature Tc is the work ceiling temperature of LED.LED lamp D1 and thermistor R2 mechanically link together, and are used to detect the temperature of LED lamp D1.
When LED lamp D1 temperature was low, thermistor R2 resistance value was very big, and PNP triode Q1 produces the bias current conducting by resistance R 1,
After detecting LED lamp D1 temperature and reaching certain working temperature, thermistor R2 diminishes with the last reduction resistance value of temperature, and LED lamp D1 starts working, when LED lamp D1 temperature near critical temperature Tc, can go out negative feedback process.
Its workflow is as follows:
LED lamp D1 temperature rising → thermistor R2 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 (2)
1. LED overheating protection circuit, comprise DC power supply (BT1), it is characterized in that: the positive power source terminal of this DC power supply (BT1) is connected the emitter of PNP triode (Q1), and the negative power end of the collector electrode of this PNP triode (Q1) and described DC power supply (BT1) powers to the load;
Between the base stage of described PNP triode (Q1) and the collector electrode and be connected to resistance (R1), between the base stage of described PNP triode (Q1) and the emitter and be connected to thermistor (R2), this thermistor (R2) is near described load.
2. LED overheating protection circuit according to claim 1; it is characterized in that: described load is LED lamp (D1); the anode of this LED lamp (D1) connects the collector electrode of described PNP triode (Q1), and the negative electrode of this LED lamp (D1) connects the negative power end of described DC power supply (BT1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200920294169 CN201571237U (en) | 2009-12-28 | 2009-12-28 | LED overheating protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200920294169 CN201571237U (en) | 2009-12-28 | 2009-12-28 | LED overheating protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201571237U true CN201571237U (en) | 2010-09-01 |
Family
ID=42663535
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200920294169 Expired - Fee Related CN201571237U (en) | 2009-12-28 | 2009-12-28 | LED overheating protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201571237U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102269041A (en) * | 2011-08-26 | 2011-12-07 | 龚文资 | Alarm circuit for poor heat radiation of automobile engine water tank |
| CN102593790A (en) * | 2011-01-05 | 2012-07-18 | 海洋王照明科技股份有限公司 | Lighting fixture overheating protection circuit and lighting fixture thereof |
| CN105140997A (en) * | 2015-09-09 | 2015-12-09 | 成都川睿科技有限公司 | Intelligent lamp charger of intelligent traffic system |
-
2009
- 2009-12-28 CN CN 200920294169 patent/CN201571237U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102593790A (en) * | 2011-01-05 | 2012-07-18 | 海洋王照明科技股份有限公司 | Lighting fixture overheating protection circuit and lighting fixture thereof |
| CN102593790B (en) * | 2011-01-05 | 2015-01-07 | 海洋王照明科技股份有限公司 | Lighting fixture overheating protection circuit and lighting fixture thereof |
| CN102269041A (en) * | 2011-08-26 | 2011-12-07 | 龚文资 | Alarm circuit for poor heat radiation of automobile engine water tank |
| CN105140997A (en) * | 2015-09-09 | 2015-12-09 | 成都川睿科技有限公司 | Intelligent lamp charger of intelligent traffic system |
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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 |