CN203261005U - LED constant-current over-temperature protection circuit and LED lamp - Google Patents

LED constant-current over-temperature protection circuit and LED lamp Download PDF

Info

Publication number
CN203261005U
CN203261005U CN 201320205182 CN201320205182U CN203261005U CN 203261005 U CN203261005 U CN 203261005U CN 201320205182 CN201320205182 CN 201320205182 CN 201320205182 U CN201320205182 U CN 201320205182U CN 203261005 U CN203261005 U CN 203261005U
Authority
CN
China
Prior art keywords
resistance
triode
control circuit
led
circuit
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.)
Active
Application number
CN 201320205182
Other languages
Chinese (zh)
Inventor
魏秋兰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Skyworth RGB Electronics Co Ltd
Original Assignee
Shenzhen Skyworth RGB Electronics Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Shenzhen Skyworth RGB Electronics Co Ltd filed Critical Shenzhen Skyworth RGB Electronics Co Ltd
Priority to CN 201320205182 priority Critical patent/CN203261005U/en
Application granted granted Critical
Publication of CN203261005U publication Critical patent/CN203261005U/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Abstract

The utility model provides an LED constant-current over-temperature protection circuit and an LED lamp. The LED constant-current over-temperature protection circuit is connected with an LED lamp, and the LED lamp is equipped with radiating fins. The LED constant-current over-temperature protection circuit comprises a temperature detection circuit, a temperature control circuit and a constant current control circuit, wherein an output end of the temperature detection circuit is connected with an input end of the temperature control circuit, an output end of the temperature control circuit is connected with an input end of the constant current control circuit, and an output end of the constant current control circuit is connected with the LED lamp. The utility model provides further provides the LED lamp including the LED constant-current over-temperature protection circuit. With the LED constant-current over-temperature protection circuit and the LED lamp which are provided by the utility model, the problem that the temperature of an LED lamp is too high in the prior art is solved, safety and reliability are achieved, the circuit is simple, and the production cost can be effectively reduced.

Description

A kind of LED constant current thermal-shutdown circuit and LED light fixture
Technical field
The utility model belongs to the LED field, relates in particular to a kind of LED constant current thermal-shutdown circuit and LED light fixture.
Background technology
The LED lamp of use high brightness is done light source has become a kind of development trend at present, although and high-brightness LED can send enough light when using, to reduce the usage quantity of LED, but it can produce amount of heat, under regular service conditions, how many work lumens of LED is, can produce how high temperature to LED can expect.But when fault occured, excess Temperature can make the brightness of LED produce decay and even damage LED.Therefore, the LED light fixture needs a kind of thermal-shutdown circuit, deals with the situation of this excess temperature.And thermal-shutdown circuit of the prior art, the general chip that uses special use, cost is high, and circuit is complicated.
The utility model content
The purpose of this utility model is to provide a kind of thermal-shutdown circuit, is intended to solve the problem that there is excess Temperature in LED light fixture in prior art.In order to solve the problems of the technologies described above, the utility model adopts following scheme to be achieved:
A kind of LED constant current thermal-shutdown circuit; be connected with the LED lamp; described LED lamp is equipped with fin; described LED constant current thermal-shutdown circuit also comprises: temperature sensing circuit, temperature-control circuit and constant-current control circuit; the output of described temperature sensing circuit is connected with the input of described temperature-control circuit; the output of described temperature-control circuit is connected with the input of described constant-current control circuit, and the output of described constant-current control circuit is connected with described LED lamp.
Described temperature sensing circuit comprises thermistor, and described thermistor is installed on the fin of described LED lamp.
Described thermistor is semistor.
Described temperature-control circuit comprises the first resistance, the second resistance, the 3rd resistance and three end adjustable shunt reference sources;
The first termination stabilized voltage power supply of described the first resistance, the second end of described the first resistance is by described the second grounding through resistance, described thermistor is in parallel with described the second resistance, the reference utmost point of described three end adjustable shunt reference sources is connected with the second end of described the first resistance, the plus earth of described three end adjustable shunt reference sources, the negative electrode of described three end adjustable shunt reference sources is connected with the first end of described the 3rd resistance.
Described constant-current control circuit comprises the 4th resistance, the 5th resistance, the 6th resistance, the first triode and the second triode;
The first end of described the 4th resistance is connected with the collector electrode of described the first triode, the second end of described the 4th resistance is connected with the second end of described the 3rd resistance, the second end of described the 4th resistance also is connected with the base stage of described the first triode, the second end of described the 4th resistance also is connected with the collector electrode of described the second triode by described the 5th resistance, the emitter of described the first triode is by described the 6th grounding through resistance, the emitter of described the first triode also is connected with the base stage of described the second triode, the grounded emitter of described the second triode.
Described the first triode is NPN type triode.
Described the second triode is NPN type triode.
Another purpose of the present utility model is to provide a kind of LED light fixture, comprises above-mentioned LED constant current thermal-shutdown circuit.
The LED constant current thermal-shutdown circuit that the utility model provides and LED light fixture have solved the too high problem of LED light temperature that exists in the prior art, and safe and reliable, circuit is simple, can effectively reduce production costs simultaneously.
Description of drawings
Fig. 1 is the theory diagram of the constant current thermal-shutdown circuit that provides of the utility model;
Fig. 2 is the detailed circuit diagram of the constant current thermal-shutdown circuit that provides of the utility model.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explaining the utility model, and be not used in restriction the utility model.
The detailed description embodiment is as follows:
With reference to figure 1; a kind of LED constant current thermal-shutdown circuit 10; be connected with LED lamp 4; LED constant current thermal-shutdown circuit 10 also comprises: temperature sensing circuit 1, temperature-control circuit 2 and constant-current control circuit 3; the output of temperature sensing circuit 1 is connected with the input of temperature-control circuit 2; the output of temperature-control circuit 2 is connected with the input of constant-current control circuit 3, and the output of constant-current control circuit 3 is connected with LED lamp 4.
Temperature sensing circuit 1 comprises thermistor RT1, and the first end of thermistor RT1 is the output of temperature sensing circuit 1, and LED lamp 4 is furnished with fin, and thermistor RT1 is installed on the fin of LED lamp 4.
Thermistor RT1 is semistor.
Temperature-control circuit 2 comprises the first resistance R 1, the second resistance R 2, the 3rd resistance R 3 and three end adjustable shunt reference source TL431;
First termination stabilized voltage power supply+VCC of the first resistance R 1, the second end of the first resistance R 1 is by the second resistance R 2 ground connection, the second end of the first resistance R 1 is the input of temperature-control circuit 2, thermistor RT1 is in parallel with the second resistance R 2, the reference utmost point of three end adjustable shunt reference source TL431 is connected with the second end of the first resistance R 1, the plus earth of three end adjustable shunt reference source TL431, the negative electrode of three end adjustable shunt reference source TL431 is connected with the first end of the 3rd resistance R 3, and the second end of the 3rd resistance R 3 is the output of temperature-control circuit 2.
Constant-current control circuit 3 comprises the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the first triode Q1 and the second triode Q2;
The first end of the 4th resistance R 4 is connected with the collector electrode of the first triode Q1; The second end of the 4th resistance R 4 is connected with the second end of the 3rd resistance R 3; The first end of the 4th resistance R 4 is the output of constant-current control circuit 3; The second end of the 4th resistance R 4 is the input of constant-current control circuit 3; The second end of the 4th resistance R 4 also is connected with the base stage of the first triode Q1; The second end of the 4th resistance R 4 also is connected with the collector electrode of the second triode Q2 by the 5th resistance R 5; The emitter of the first triode Q1 is by the 6th resistance R 6 ground connection; The emitter of the first triode Q1 also is connected with the base stage of the second triode Q2; The grounded emitter of the second triode Q2.
The first triode Q1 is NPN type triode.
The second triode Q2 is NPN type triode.
Another purpose of the present utility model is to provide a kind of LED light fixture, comprises above-mentioned LED constant current thermal-shutdown circuit 10.
The elaboration operation principle is as follows:
Temperature sensing circuit 1 can detect the variation of temperature, and this temperature detection signal is sent to temperature-control circuit 2, when excess Temperature, temperature-control circuit 2 can send current controling signal to constant-current control circuit 3, constant-current control circuit 3 guarantees the normal operation of ELD lamp by reducing the current reduction temperature by LED lamp 4.
Particularly, when when normal operation, the suitable operating voltage of power LED+provide, give the first triode Q1 base stage operating current by the 4th resistance R 4, the first triode Q1 conducting, LED lamp 4 is started working, and LED lamp 4 is by the 6th resistance R 6, and this moment, electric current was by the second triode Q2 conducting voltage V B/ R6 sets, wherein V BIt is the base voltage of the second triode Q2.
When the electric current of LED lamp 4 increases, namely the second triode Q2 base current strengthens, according to the triode amplification principle, pressure drop between the second triode Q2 collector electrode and emitter reduces, collector current increases, thereby makes the base bleeder current of the first triode Q1 that its electric current is reduced, and the collector current of the first triode Q1 descends, make electric current drop to the setting current work, thereby keep LED stably to work.
When LED lamp 4 excess Temperature; the thermistor of positive temperature coefficient that can be by being arranged on the LED fin detects, and when temperature was raised to the temperature of setting, the thermistor resistance raise; three end adjustable shunt reference source TL431 raise with reference to pole tension; when reaching operating current, three end adjustable shunt reference source TL431 start working, and the base current of the first triode Q1 is shunted; the conducting degree of the first triode Q1 is descended; the LED electric current reduces, and heat descends, and has played the overheat protector effect.
The LED constant current thermal-shutdown circuit that the utility model provides and LED light fixture have solved the problem of the excess Temperature that exists in the prior art, and safe and reliable, circuit is simple, can effectively reduce production costs simultaneously.
The above is only preferred embodiment of the present utility model; not in order to limit the utility model; all any modifications of doing within spirit of the present utility model and principle, be equal to and replace and improvement etc., within all should being included in protection range of the present utility model.

Claims (8)

1. LED constant current thermal-shutdown circuit; be connected with the LED lamp; described LED constant current thermal-shutdown circuit also comprises: temperature sensing circuit, temperature-control circuit and constant-current control circuit; the output of described temperature sensing circuit is connected with the input of described temperature-control circuit; the output of described temperature-control circuit is connected with the input of described constant-current control circuit, and the output of described constant-current control circuit is connected with described LED lamp.
2. LED constant current thermal-shutdown circuit as claimed in claim 1; it is characterized in that, described temperature sensing circuit comprises thermistor, and the first end of described thermistor is the output of described temperature sensing circuit; described LED lamp is furnished with fin, and described thermistor is installed on described fin.
3. LED constant current thermal-shutdown circuit as claimed in claim 2, is characterized in that, described thermistor is semistor.
4. LED constant current thermal-shutdown circuit as claimed in claim 2, is characterized in that, described temperature-control circuit comprises the first resistance, the second resistance, the 3rd resistance and three end adjustable shunt reference sources;
The first termination stabilized voltage power supply of described the first resistance; The second end of described the first resistance is by described the second grounding through resistance; The second end of described the first resistance is the input of described temperature-control circuit; Described thermistor is in parallel with described the second resistance; The reference utmost point of described three end adjustable shunt reference sources is connected with the second end of described the first resistance; The plus earth of described three end adjustable shunt reference sources; The negative electrode of described three end adjustable shunt reference sources is connected with the first end of described the 3rd resistance; The second end of described the 3rd resistance is the output of described temperature-control circuit.
5. LED constant current thermal-shutdown circuit as claimed in claim 4, is characterized in that, described constant-current control circuit comprises the 4th resistance, the 5th resistance, the 6th resistance, the first triode and the second triode;
The first end of described the 4th resistance is connected with the collector electrode of described the first triode; The second end of described the 4th resistance is connected with the second end of described the 3rd resistance; The first end of described the 4th resistance is the output of described constant-current control circuit; The second end of described the 4th resistance is the input of described constant-current control circuit; The second end of described the 4th resistance also is connected with the base stage of described the first triode; The second end of described the 4th resistance also is connected with the collector electrode of described the second triode by described the 5th resistance; The emitter of described the first triode is by described the 6th grounding through resistance; The emitter of described the first triode also is connected with the base stage of described the second triode; The grounded emitter of described the second triode.
6. LED constant current thermal-shutdown circuit as claimed in claim 5, is characterized in that, described the first triode is NPN type triode.
7. LED constant current thermal-shutdown circuit as claimed in claim 5, is characterized in that, described the second triode is NPN type triode.
8. a LED light fixture, is characterized in that, comprises the described LED constant current of any one thermal-shutdown circuit in claim 1-7.
CN 201320205182 2013-04-22 2013-04-22 LED constant-current over-temperature protection circuit and LED lamp Active CN203261005U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 201320205182 CN203261005U (en) 2013-04-22 2013-04-22 LED constant-current over-temperature protection circuit and LED lamp

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 201320205182 CN203261005U (en) 2013-04-22 2013-04-22 LED constant-current over-temperature protection circuit and LED lamp

Publications (1)

Publication Number Publication Date
CN203261005U true CN203261005U (en) 2013-10-30

Family

ID=49473543

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 201320205182 Active CN203261005U (en) 2013-04-22 2013-04-22 LED constant-current over-temperature protection circuit and LED lamp

Country Status (1)

Country Link
CN (1) CN203261005U (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
CN105517227A (en) * 2015-12-20 2016-04-20 合肥艾斯克光电科技有限责任公司 LED lamp over-temperature protection method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
CN105517227A (en) * 2015-12-20 2016-04-20 合肥艾斯克光电科技有限责任公司 LED lamp over-temperature protection method

Similar Documents

Publication Publication Date Title
CN103687240B (en) Over-voltage over-current protection circuit and electronic installation
CN103281835A (en) LED over-temperature protection circuit applied to alternative current LED drive system
CN103281836A (en) Chip over-temperature protection circuit applied to alternative current LED drive system
CN103401209B (en) LED-backlit short-circuit protection circuit
CN204068678U (en) A kind of Switching Power Supply output over-voltage protection and thermal-shutdown circuit
CN203840609U (en) LED circuit having overheating protection function
CN203261005U (en) LED constant-current over-temperature protection circuit and LED lamp
CN102043413A (en) Temperature control circuit
CN104918385A (en) Temperature detection circuit and LED (Light-Emitting Diode) lamp provided with temperature control protection circuit
CN203504786U (en) Electromagnetic heating control circuit and electric pressure cooker
CN204795768U (en) LED constant -current drive circuit
CN204721676U (en) The LED lamp of a kind of temperature sensing circuit and band temperature control protective circuit
CN202634852U (en) Linear constant-current LED (light-emitting diode) driver
CN202679701U (en) Novel LED drive circuit
CN203840611U (en) LED circuit having overheating protection function
CN203708595U (en) Novel LED light adjustment circuit
CN204104196U (en) LED lamp and excess temperature, overvoltage crowbar
CN203027547U (en) LED (light-emitting diode) intelligent fan radiating system control circuit
CN203590537U (en) High efficiency LED drive circuit
CN103052212A (en) Over-current protection light emitting diode (LED) lamp
CN102883506A (en) Method for dynamically controlling temperature of central area of array light emitting diode (LED) lighting lamp
CN203504157U (en) IGBT protection circuit
CN202141532U (en) Circuit heating state display device
CN202889689U (en) Led constant current circuit
CN202634853U (en) Power-saving light emitting diode driver

Legal Events

Date Code Title Description
C14 Grant of patent or utility model
GR01 Patent grant