CN203608424U - LED constant current drive circuit with over-temperature buffer protection function - Google Patents

LED constant current drive circuit with over-temperature buffer protection function Download PDF

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CN203608424U
CN203608424U CN201320768728.XU CN201320768728U CN203608424U CN 203608424 U CN203608424 U CN 203608424U CN 201320768728 U CN201320768728 U CN 201320768728U CN 203608424 U CN203608424 U CN 203608424U
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module
inverter
output
hysteresis
input
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曾以成
陶亮
李志军
武世明
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Xiangtan University
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Xiangtan University
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Abstract

The utility model discloses an LED constant current drive circuit with an over-temperature buffer protection function. The circuit comprises a constant current driver module, a hysteresis and over-temperature buffer module, a hysteresis and over-temperature turn-off module, and a time-delay reset module. The hysteresis and over-temperature turn-off module, the constant current driver module, the hysteresis and over-temperature buffer module and the time-delay reset module are connected successively. The time-delay reset module is connected to the constant current driver module. The hysteresis and over-temperature buffer module can achieve regulation of a time domain and a temperature range, so that application of the circuit is more flexible, and the operating interval and application range of the circuit are enlarged. Besides, the circuit is designed with double temperature hysteresis intervals, sizes of which can be adjusted via externally-connected resistors, so that the circuit is prevented from thermal oscillation.

Description

A kind of LED constant-current drive circuit with excess temperature buffering protection function
Technical field
The utility model relates to a kind of LED constant-current drive circuit, particularly a kind of LED constant-current drive circuit with excess temperature buffering protection function.
Background technology
Along with the generally application of large power white light LED in light decoration and illumination, large power white light LED drives the demand of chip also increasing, and the increase of power output is risen obviously chip temperature, affects the useful life of LED.At present thermal-shutdown circuit exists circuit in the shortcoming that reached warm spot and turn-off immediately, has limited use value and the scope of application of thermal-shutdown circuit.
Summary of the invention
In order to solve the problems of the technologies described above, the utility model provides a kind of LED constant-current drive circuit with excess temperature buffering protection function.
The technical scheme that the utility model addresses the above problem is: a kind of LED constant-current drive circuit with excess temperature buffering protection function; comprise that constant-current driven module, hysteresis and excess temperature buffer module, hysteresis and excess temperature turn-off module and time-delay reset module; described hysteresis is turn-offed module with excess temperature and is connected with constant-current driven module; constant-current driven module is connected with excess temperature buffer module with hysteresis; hysteresis is connected with time-delay reset module with excess temperature buffer module, and time-delay reset module is connected with constant-current driven module.
Described constant-current driven module comprises bandgap voltage reference, operational amplifier, the one NMOS pipe, the 2nd NMOS pipe, the first resistance and the second resistance, described bandgap voltage reference has three outputs, its first output respectively with the inverting input of operational amplifier, hysteresis is connected with excess temperature buffer module, its second output turn-offs module with hysteresis and excess temperature and is connected, its the 3rd output is successively through the first resistance, after the second resistance, be connected with the in-phase input end of operational amplifier, the output of described operational amplifier respectively with the grid of a NMOS pipe, the grid of the 2nd NMOS pipe, hysteresis is turn-offed module with excess temperature and is connected, the source electrode of the one NMOS pipe, the source grounding of the 2nd NMOS pipe, the drain electrode of the one NMOS pipe is connected with time-delay reset module, the drain electrode of the 2nd NMOS pipe is connected with LED lamp.
Described hysteresis and excess temperature turn-off module and comprise the first voltage generation circuit, the first comparator, the first reverser, the second inverter and the 4th NMOS pipe, the in-phase input end of described the first comparator is connected with the second output of bandgap voltage reference, the inverting input of the first comparator is connected with the first voltage generation circuit, the output of the first comparator is successively through the first inverter, the second inverter is connected with the first voltage generation circuit, the output of described the first comparator is connected with the grid of the 4th NMOS pipe, the source ground of the 4th NMOS pipe, the 4th drain electrode of NMOS pipe and the output of operational amplifier are connected.
Described hysteresis and excess temperature buffer module comprise that second voltage produces circuit, the second comparator, the 3rd inverter, the 4th inverter, the in-phase input end of described the second comparator is connected with the first output of bandgap voltage reference, the inverting input of the second comparator produces circuit with second voltage and is connected, the output of the second comparator produces circuit through the 3rd inverter, the 4th inverter with second voltage successively and is connected, and the output of the 4th inverter is connected with time-delay reset module.
Described time-delay reset module comprises the 5th inverter, hex inverter, the 7th inverter, two input nand gates, two input NOR gate, delay circuit and the 3rd NMOS pipe, the input of described the 5th inverter is connected with the output of the 4th inverter, the output of the 5th inverter respectively with delay circuit, an input of two input nand gates is connected, another input of two input nand gates is connected with delay circuit, the output of two input nand gates is connected with the input of hex inverter, the output of hex inverter is connected with an input of two input NOR gate, another input of two input NOR gate is connected with the output of the 4th inverter, the output of two input NOR gate is connected with the input of the 7th inverter, the output of the 7th inverter is connected with the grid of the 3rd NMOS pipe, the source electrode of the 3rd NMOS pipe is connected with the drain electrode of a described NMOS pipe, the drain electrode of the 3rd NMOS pipe respectively with the first resistance, the second resistance is connected.
The beneficial effects of the utility model are:
1) the utility model is in the time that normal work reaches design temperature control point, drive current is not to become at once 0, but be down to the constant drive current of setting, thereby circuit power consumption is declined, be conducive to circuit heat radiation, impel circuit to recover normal work, and drive current fall can be regulated by outer meeting resistance, avoid LED light fixture because the large light decay of overheated generation causes early failure, extended the useful life of LED;
2) hysteresis of the present utility model and excess temperature buffer module can realize the adjusting of time domain and temperature range, make circuit application more be rich in flexibility, have promoted operation interval and the range of application of circuit;
3) the utility model has designed two temperature hysteresis interval, and the large I in temperature hysteresis interval regulates by outer meeting resistance, has avoided circuit generation thermal oscillation.
Accompanying drawing explanation
Fig. 1 is structured flowchart of the present utility model.
Fig. 2 is circuit theory diagrams of the present utility model.
Embodiment
Below in conjunction with drawings and Examples, the utility model is further described.
As shown in Figure 1, the utility model comprises that constant-current driven module 1, hysteresis and excess temperature buffer module 3, hysteresis and excess temperature turn-off module 2 and time-delay reset module 4, described hysteresis is turn-offed module 2 with excess temperature and is connected with constant-current driven module 1, constant-current driven module 1 is connected with excess temperature buffer module 3 with hysteresis, hysteresis is connected with time-delay reset module 4 with excess temperature buffer module 3, and time-delay reset module 4 is connected with constant-current driven module 1.
As shown in Figure 2, described constant-current driven module 1 comprises that bandgap voltage reference, operational amplifier OPA, NMOS manage M 1, NMOS manages M 2, resistance R sense1and resistance R sense2described bandgap voltage reference has three outputs, its first output (1.54V) is connected with inverting input, hysteresis and the excess temperature buffer module 3 of operational amplifier OPA respectively, its second output (2V) turn-offs module 2 with hysteresis and excess temperature and is connected, and its 3rd output (3.28V) is successively through resistance R sense1, resistance R sense2be connected with the in-phase input end of operational amplifier OPA afterwards, the output of described operational amplifier OPA is managed M with NMOS respectively 1grid, NMOS manage M 2grid, hysteresis and excess temperature turn-off module 2 and be connected, NMOS manages M 1source electrode, NMOS manage M 2source grounding, NMOS manages M 1drain electrode be connected with time-delay reset module 4, NMOS manages M 2drain electrode be connected with LED lamp.
Described hysteresis and excess temperature turn-off module 2 and comprise voltage generation circuit PTAT1, comparator C OM1, reverser 21, inverter 22 and NMOS pipe M 4the in-phase input end of described comparator C OM1 is connected with the second output of bandgap voltage reference, the inverting input of comparator C OM1 is connected with voltage generation circuit PTAT1, the output of comparator C OM1 is connected with voltage generation circuit PTAT1 through reverser 21, inverter 22 successively, the output of described comparator C OM1 and NMOS pipe M 4grid be connected, NMOS manages M 4source ground, NMOS manages M 4drain electrode be connected with the output of operational amplifier OPA.
Described hysteresis and excess temperature buffer module 3 comprise voltage generation circuit PTAT2, comparator C OM2, inverter 31, inverter 32, the in-phase input end of described comparator C OM2 is connected with the first output of bandgap voltage reference, the inverting input of comparator C OM2 is connected with voltage generation circuit PTAT2, the output of comparator C OM2 is connected with voltage generation circuit PTAT2 through inverter 31, inverter 32 successively, and the output of inverter 32 is connected with time-delay reset module 4.
Described time-delay reset module 4 comprises inverter 41, inverter 42, inverter 43, two input nand gate NAND, two input NOR gate NOR, delay circuit and NMOS pipe M 3, the input of described inverter 41 is connected with the output of inverter 32, the output of inverter 41 respectively with delay circuit, an input of two input nand gate NAND is connected, another input of two input nand gate NAND is connected with delay circuit, the output of two input nand gate NAND is connected with the input of inverter 42, the output of inverter 42 is connected with an input of two input NOR gate NOR, another input of two input NOR gate NOR is connected with the output of inverter 32, the output of two input NOR gate NOR is connected with the input of inverter 43, the output of inverter 43 and NMOS pipe M 3grid be connected, NMOS manages M 3source electrode and described NMOS pipe M 1drain electrode be connected, NMOS manages M 3drain electrode respectively with resistance R sense1, resistance R sense2be connected.
Operation principle of the present utility model is as follows: under normal working temperature, the voltage generation circuit PTAT2 of described hysteresis and excess temperature buffer module 3 produces the voltage that voltage Vptat is less than the 1.54V that bandgap voltage reference provides, and Vm is that high level makes NMOS pipe M 3conducting, sample resistance R sense2by short circuit.Same described hysteresis and excess temperature turn-off the lag function of module 2 and close, and the lag function of described hysteresis and excess temperature buffer module 3 is also in closed condition; Vptat is also less than the voltage of the 2.0V that bandgap voltage reference provides, and Vp is low level, makes NMOS pipe M 4turn-off cut-off, do not affect NMOS pipe M 1normal work.
In the time that temperature forward reaches the protection temperature threshold of first setting, now the voltage generation circuit PTAT2 of described hysteresis and excess temperature buffer module produces the voltage that voltage Vptat is greater than the 1.54V that bandgap voltage reference provides, and Vm is that low level makes NMOS pipe M 3turn-off sample resistance R sense2place in circuit work, I senseand I lEDdecline, make equally the lag function of hysteresis and excess temperature shutoff module 2 open-minded, circuit enters buffer stage.Now hysteresis and excess temperature turn-off the voltage that voltage Vptat that module 2 produces is still less than the 2.0V that bandgap voltage reference provides, and Vp is low level, makes NMOS pipe M 4turn-off cut-off, do not affect NMOS pipe M 1normal work.
Temperature is after the buffering heat radiation of buffer stage, and temperature is declined, and also may be subject to other and can not resist factor to disturb, and temperature continues to rise, so there will be following two kinds of situations:
Figure DEST_PATH_IMAGE001
if circuit temperature starts to decline, described NMOS pipe M 1still keep work, circuit is in buffering area,, because the temperature hysteresis function of hysteresis and excess temperature buffer module 3 is opened, temperature continues to decline after dropping to the protection temperature threshold of first setting, and after certain sluggish temperature, Vm is high level, R sense2by short circuit, circuit recovers normal work, and the lag function of hysteresis and excess temperature buffer module 3 is closed.Always in running order at excess temperature buffer stage circuit, realize the function of hysteresis excess temperature buffer protection;
Figure 593884DEST_PATH_IMAGE002
if because other factors interference, the timely radiating and cooling of circuit, circuit temperature continues to rise, and for preventing circuit malfunction, hysteresis and excess temperature turn-off module 2 and work.In the time that temperature forward reaches the protection temperature threshold of second setting; the voltage generation circuit PTAT1 that now hysteresis and excess temperature turn-off module 2 produces the voltage that voltage Vptat is greater than the 2V that bandgap voltage reference provides; comparator C OM1 output low level becomes high level through inverter 21, and NMOS manages M 4conducting, closes NMOS pipe M 1output, carries out overheat protector.Vn is low level simultaneously, and the lag function in hysteresis and excess temperature shutoff module 2 is open-minded.Temperature declines until after certain sluggish temperature, NMOS manages M 1again normally work, drive current returns 350mA, and circuit is normally worked, and has realized the temperature hysteresis function of overheat protector.
Enter behind buffering area at circuit, avoid circuit for a long time in buffering area, when the lasting time that exceedes setting in the time of buffer stage of circuit, time-delay reset module 4 is just drawn high switching tube grid voltage, makes switching tube M 3conducting, circuit recovers normal work, and the delay time of circuit is set as required.

Claims (5)

1. one kind has the LED constant-current drive circuit of excess temperature buffering protection function; it is characterized in that: comprise that constant-current driven module, hysteresis and excess temperature buffer module, hysteresis and excess temperature turn-off module and time-delay reset module; described hysteresis is turn-offed module with excess temperature and is connected with constant-current driven module; constant-current driven module is connected with excess temperature buffer module with hysteresis; hysteresis is connected with time-delay reset module with excess temperature buffer module, and time-delay reset module is connected with constant-current driven module.
2. the LED constant-current drive circuit with excess temperature buffering protection function according to claim 1, it is characterized in that: described constant-current driven module comprises bandgap voltage reference, operational amplifier, the one NMOS pipe, the 2nd NMOS pipe, the first resistance and the second resistance, described bandgap voltage reference has three outputs, its first output respectively with the inverting input of operational amplifier, hysteresis is connected with excess temperature buffer module, its second output turn-offs module with hysteresis and excess temperature and is connected, its the 3rd output is successively through the first resistance, after the second resistance, be connected with the in-phase input end of operational amplifier, the output of described operational amplifier respectively with the grid of a NMOS pipe, the grid of the 2nd NMOS pipe, hysteresis is turn-offed module with excess temperature and is connected, the source electrode of the one NMOS pipe, the source grounding of the 2nd NMOS pipe, the drain electrode of the one NMOS pipe is connected with time-delay reset module, the drain electrode of the 2nd NMOS pipe is connected with LED lamp.
3. the LED constant-current drive circuit with excess temperature buffering protection function according to claim 2, it is characterized in that: described hysteresis and excess temperature turn-off module and comprise the first voltage generation circuit, the first comparator, the first reverser, the second inverter and the 4th NMOS pipe, the in-phase input end of described the first comparator is connected with the second output of bandgap voltage reference, the inverting input of the first comparator is connected with the first voltage generation circuit, the output of the first comparator is successively through the first inverter, the second inverter is connected with the first voltage generation circuit, the output of described the first comparator is connected with the grid of the 4th NMOS pipe, the source ground of the 4th NMOS pipe, the 4th drain electrode of NMOS pipe and the output of operational amplifier are connected.
4. the LED constant-current drive circuit with excess temperature buffering protection function according to claim 3, it is characterized in that: described hysteresis and excess temperature buffer module comprise that second voltage produces circuit, the second comparator, the 3rd inverter, the 4th inverter, the in-phase input end of described the second comparator is connected with the first output of bandgap voltage reference, the inverting input of the second comparator produces circuit with second voltage and is connected, the output of the second comparator is successively through the 3rd inverter, the 4th inverter produces circuit with second voltage and is connected, the output of the 4th inverter is connected with time-delay reset module.
5. the LED constant-current drive circuit with excess temperature buffering protection function according to claim 4, it is characterized in that: described time-delay reset module comprises the 5th inverter, hex inverter, the 7th inverter, two input nand gates, two input NOR gate, delay circuit and the 3rd NMOS pipe, the input of described the 5th inverter is connected with the output of the 4th inverter, the output of the 5th inverter respectively with delay circuit, an input of two input nand gates is connected, another input of two input nand gates is connected with delay circuit, the output of two input nand gates is connected with the input of hex inverter, the output of hex inverter is connected with an input of two input NOR gate, another input of two input NOR gate is connected with the output of the 4th inverter, the output of two input NOR gate is connected with the input of the 7th inverter, the output of the 7th inverter is connected with the grid of the 3rd NMOS pipe, the source electrode of the 3rd NMOS pipe is connected with the drain electrode of a described NMOS pipe, the drain electrode of the 3rd NMOS pipe respectively with the first resistance, the second resistance is connected.
CN201320768728.XU 2013-11-29 2013-11-29 LED constant current drive circuit with over-temperature buffer protection function Expired - Fee Related CN203608424U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105357811A (en) * 2015-12-21 2016-02-24 佛山市南海区联合广东新光源产业创新中心 LED constant-current drive circuit with over-temperature protection function
CN112601327A (en) * 2020-12-21 2021-04-02 京东方科技集团股份有限公司 Temperature control circuit and light emitting device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105357811A (en) * 2015-12-21 2016-02-24 佛山市南海区联合广东新光源产业创新中心 LED constant-current drive circuit with over-temperature protection function
CN112601327A (en) * 2020-12-21 2021-04-02 京东方科技集团股份有限公司 Temperature control circuit and light emitting device

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