CN105338694A - Protection circuit for LED light fixture - Google Patents
Protection circuit for LED light fixture Download PDFInfo
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- CN105338694A CN105338694A CN201510686912.3A CN201510686912A CN105338694A CN 105338694 A CN105338694 A CN 105338694A CN 201510686912 A CN201510686912 A CN 201510686912A CN 105338694 A CN105338694 A CN 105338694A
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Abstract
The invention provides a protection circuit for an LED light fixture. The protection circuit for an LED light fixture includes a temperature control protection circuit, a high voltage open circuit and an LED connection circuit, wherein the LED connection circuit is formed through series-parallel connection of LED chips; the temperature control protection circuit is arranged on an LED lamp panel, and comprises an LED driver chip U2, a thermistor NTC1 and an MOS transistor Q2; the high voltage open circuit includes a controllable precision stabilized power supply U1 and an MOS transistor Q1; the temperature of the LED lamp panel can be measured by the thermistor; the magnitude of the LED output current can be controlled through temperature variation; and the output power is suitably adjusted to reduce heat generation of LED so that the luminous flux and the service life of the LED can be guaranteed maximumly. When the input voltage of an external power supply VCC is greater than 36V and the potential of the reference electrode of the controllable precision stabilized power supply U1 is greater than 2.5V, the controllable precision stabilized power supply U1 is conducted and the MOS transistor Q1 is disconnected and the input high voltage is added to the MOS transistor Q1 so that high voltage protection is formed on other components in the circuit.
Description
Technical field
The present invention relates to LED lamp, especially LED lamp is had to the function of temperature protection and high pressure disconnection.
Background technology
Heat dissipation problem is that LED needs one of problem solved, the heater element mainly LED chip of LED lamp always, and some LED chips are concentrated and are fitted in LED lamp panel, and during LED lamp work, LED lamp panel can produce amount of heat.The heat dissipating method of current LED lamp mainly adopts radiator and fan to dispel the heat to LED lamp panel.But for some heat-dissipating space is limited can not the LED lamp of installation of heat radiator, owing to not arranging heat abstractor, operationally temperature is easily too high to make this kind of light fixture, and the luminous flux of LED and life-span can be subject to certain impact.
LED lamp, especially LED car lamp, especially carry out switching over frequently with needs, and during switching, power supply likely can produce instantaneous pressure pulse to LED circuit, produces infringement to circuit.Existing LED car lamp does not generally arrange high pressure open circuit, the hidden danger making LED car lamp there is circuit to be injured by high-voltage pulse.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of LED lamp protective circuit, by regulating the heat of the size control LED of LED output current, ensures luminous flux and the life-span of LED; Can prevent the high-voltage pulse within 200V from producing infringement to LED circuit.
For solving the problems of the technologies described above, technical scheme of the present invention is: a kind of LED lamp protective circuit, comprises temperature control protective circuit, high pressure open circuit and the LED connecting circuit be connected by connection in series-parallel by LED chip;
Described temperature control protective circuit is located in LED lamp panel, and temperature control protective circuit comprises LED drive chip U2, thermistor NTC1 and metal-oxide-semiconductor Q2; One end of described thermistor NTC1 is connected with the light modulation pin ACTL of LED drive chip U2, other end ground connection; The control pin GATE of LED drive chip U2 is connected with the grid of metal-oxide-semiconductor Q2, the source ground of metal-oxide-semiconductor Q2, and the drain electrode of metal-oxide-semiconductor Q2 is connected by the output of inductance L 1 with LED connecting circuit; External power source VCC is connected with the input of LED connecting circuit by resistance RZ1;
Described high pressure open circuit comprises controllable accurate source of stable pressure U1 and metal-oxide-semiconductor Q1; External power source VCC is connected with the input of LED connecting circuit, external power source VCC is connected with the reference pole of controllable accurate source of stable pressure U1 by resistance R1, external power source VCC is connected with the negative electrode of controllable accurate source of stable pressure U1 by resistance R2, resistance R4 is connected with between the anode of controllable accurate source of stable pressure U1 and reference pole, and the plus earth GND0 of controllable accurate source of stable pressure U1; The negative electrode of controllable accurate source of stable pressure U1 is connected with the grid of metal-oxide-semiconductor Q1 by forward diode D1, and the grid of metal-oxide-semiconductor passes through the source ground GND0 of ground connection GND0, metal-oxide-semiconductor Q1 after resistance R3 parallel with one another and voltage stabilizing didoe Z1, the grounded drain GND of metal-oxide-semiconductor Q1.
Operation principle of the present invention: during light fixture work, the temperature of LED lamp panel can raise, when temperature rises to set point time, the resistance of thermistor NTC1 changes, thus cause the voltage at thermistor NTC1 two ends to change, the voltage signal of change is input to the light modulation pin ACTL of LED drive chip, then controls cut-offfing of metal-oxide-semiconductor Q2 by controlling pin GATE, thus the size of regulation output LED current.In theory, when temperature exceedes set point, temperature is higher, and LED output current is less, this function be mainly applied in heat-dissipating space limited when, suitable regulation output power, thus the luminous flux and the useful life that ensure that LED to greatest extent.The normal working voltage of circuit of the present invention is 10-30V.When the input voltage of external power source VCC is higher than 36V, the current potential of the reference pole of controllable accurate source of stable pressure U1 is greater than 2.5V, now controllable accurate source of stable pressure U1 conducting, and metal-oxide-semiconductor Q1 disconnects, the high voltage of input is added on metal-oxide-semiconductor Q1, thus forms high voltage protective to other components and parts in circuit; After the input voltage of single external power source VCC returns to normal working voltage, protection is removed, and LED connecting circuit normally works.
As improvement, the pin ISP of LED drive chip U2 is connected by the input of resistance R11, RZ1 and LED connecting circuit successively; The pin ISN of LED drive chip U2 is connected with the input of LED connecting circuit by resistance R13; Electric capacity C6 is provided with between pin ISP and pin ISN.
As improvement, described external power source VCC is successively by being connected with the drain electrode of metal-oxide-semiconductor Q2 after reverse Xiao Te diode D2, magnetic bead FB1.
As improvement, described thermistor NTC1 and LED lamp panel surface are affixed the temperature sensing LED lamp panel.
As improvement, the model of described LED drive chip U2 is RT8475.
As improvement, the resistance of described resistance R1 is 68K, and the resistance of resistance R2 is 10K, and the resistance of resistance R4 is 5.1K.
As improvement, between the negative electrode of controllable accurate source of stable pressure U1 and the anode of diode D1, be provided with high-frequency diode.
As improvement, described voltage stabilizing didoe Z1 is 0.5W, 10V voltage-stabiliser tube; The resistance of resistance R3 is 10K.
As improvement, described LED connecting circuit has some LED strip parallel with one another connection branch road to be formed by connecting.
The beneficial effect that the present invention is compared with prior art brought is:
By the temperature of thermistor sensing LED lamp panel, by variations in temperature control LED output current size, suitable regulation output power, the heat reducing LED produces, thus ensure that luminous flux and the useful life of LED to greatest extent.When the input voltage of external power source VCC is higher than 36V; the current potential of the reference pole of controllable accurate source of stable pressure U1 is greater than 2.5V; now controllable accurate source of stable pressure U1 conducting; metal-oxide-semiconductor Q1 disconnects; the high voltage of input is added on metal-oxide-semiconductor Q1; thus high voltage protective is formed to other components and parts in circuit, the present invention can prevent the high-voltage pulse within 200V from producing infringement to LED circuit.
Accompanying drawing explanation
Fig. 1 is circuit diagram of the present invention.
Embodiment
Below in conjunction with Figure of description, the invention will be further described.
As shown in Figure 1, a kind of LED lamp protective circuit, comprises temperature control protective circuit, high pressure open circuit and the LED connecting circuit be connected by connection in series-parallel by LED chip.Described LED connecting circuit joins branch road by some LED strip parallel with one another and is formed by connecting.
Described temperature protection circuit is located in LED lamp panel, comprises LED drive chip U2, thermistor NTC1 and metal-oxide-semiconductor Q2.The model of described LED drive chip U2 is RT8475.Described thermistor NTC1 and LED lamp panel surface are affixed the temperature sensing LED lamp panel; One end of described thermistor NTC1 is connected with the light modulation end ACTL of LED drive chip U2, other end ground connection.The control pin GATE of LED drive chip U2 is connected with the grid of metal-oxide-semiconductor Q2, the source ground of metal-oxide-semiconductor Q2, and the drain electrode of metal-oxide-semiconductor Q2 is connected by the output of inductance L 1 with LED connecting circuit.The external power source VCC of 10-30V is connected with the input of LED connecting circuit by resistance RZ1.The pin ISP of LED drive chip U2 is connected by the input of resistance R11, RZ1 and LED connecting circuit successively; The pin ISN of LED drive chip U2 is connected with the input of LED connecting circuit by resistance R13; Electric capacity C6 is provided with between pin ISP and pin ISN.Described external power source VCC is successively by being connected with the drain electrode of metal-oxide-semiconductor Q2 after reverse Xiao Te diode D2, magnetic bead FB1.Temperature protection circuit operation principle: during light fixture work; the temperature of LED lamp panel can raise; when temperature rises to set point time; the resistance of thermistor NTC1 changes; thus cause the voltage at thermistor NTC1 two ends to change; the voltage signal of change is input to the light modulation pin ACTL of LED drive chip U2, then controls cut-offfing of metal-oxide-semiconductor Q2 by controlling pin GATE, thus the size of regulation output LED current.In theory, when temperature exceedes set point, temperature is higher, and LED output current is less, this function be mainly applied in heat-dissipating space limited when, suitable regulation output power, thus the luminous flux and the useful life that ensure that LED to greatest extent.
Described high pressure open circuit comprises controllable accurate source of stable pressure U1 and metal-oxide-semiconductor Q1, external power source VCC is connected with the input of LED connecting circuit, external power source VCC is connected with the reference pole of controllable accurate source of stable pressure U1 by resistance R1, external power source VCC is connected with the negative electrode of controllable accurate source of stable pressure U1 by resistance R2, resistance R4 is connected with between the anode of controllable accurate source of stable pressure U1 and reference pole, and the plus earth GND0 of controllable accurate source of stable pressure U1; The resistance of described resistance R1 is 68K, and the resistance of resistance R2 is 10K, and the resistance of resistance R4 is 5.1K.The negative electrode of controllable accurate source of stable pressure U1 is connected with the grid of metal-oxide-semiconductor Q1 by high-frequency diode, forward diode D1 successively, the grid of metal-oxide-semiconductor is by ground connection GND0 after resistance R3 parallel with one another and voltage stabilizing didoe Z1, and described voltage stabilizing didoe Z1 is 0.5W, 10V voltage-stabiliser tube; The resistance of resistance R3 is 10K; The grounded drain GND of the source ground GND0 of metal-oxide-semiconductor Q1, metal-oxide-semiconductor Q1.High pressure open circuit operation principle: the normal working voltage of circuit is 10-30V, when the input voltage of external power source VCC is higher than 36V, the current potential of the reference pole of controllable accurate source of stable pressure U1 is greater than 2.5V, now controllable accurate source of stable pressure U1 conducting, metal-oxide-semiconductor Q1 disconnects, the high voltage of input is added on metal-oxide-semiconductor Q1, thus forms high voltage protective to other components and parts in circuit; After the input voltage of single external power source VCC returns to normal working voltage, protection is removed, and LED connecting circuit normally works, and the present invention can prevent the high-voltage pulse within 200V from producing infringement to LED circuit.
Claims (9)
1. a LED lamp protective circuit, is characterized in that: comprise temperature control protective circuit, high pressure open circuit and the LED connecting circuit be connected by connection in series-parallel by LED chip;
Described temperature control protective circuit is located in LED lamp panel, and temperature control protective circuit comprises LED drive chip U2, thermistor NTC1 and metal-oxide-semiconductor Q2; One end of described thermistor NTC1 is connected with the light modulation pin ACTL of LED drive chip U2, other end ground connection; The control pin GATE of LED drive chip U2 is connected with the grid of metal-oxide-semiconductor Q2, the source ground of metal-oxide-semiconductor Q2, and the drain electrode of metal-oxide-semiconductor Q2 is connected by the output of inductance L 1 with LED connecting circuit; External power source VCC is connected with the input of LED connecting circuit by resistance RZ1;
Described high pressure open circuit comprises controllable accurate source of stable pressure U1 and metal-oxide-semiconductor Q1; External power source VCC is connected with the input of LED connecting circuit, external power source VCC is connected with the reference pole of controllable accurate source of stable pressure U1 by resistance R1, external power source VCC is connected with the negative electrode of controllable accurate source of stable pressure U1 by resistance R2, resistance R4 is connected with between the anode of controllable accurate source of stable pressure U1 and reference pole, and the plus earth GND0 of controllable accurate source of stable pressure U1; The negative electrode of controllable accurate source of stable pressure U1 is connected with the grid of metal-oxide-semiconductor Q1 by forward diode D1, and the grid of metal-oxide-semiconductor passes through the source ground GND0 of ground connection GND0, metal-oxide-semiconductor Q1 after resistance R3 parallel with one another and voltage stabilizing didoe Z1, the grounded drain GND of metal-oxide-semiconductor Q1.
2. a kind of LED lamp protective circuit according to claim 1, is characterized in that: the pin ISP of LED drive chip U2 is connected by the input of resistance R11, RZ1 and LED connecting circuit successively; The pin ISN of LED drive chip U2 is connected with the input of LED connecting circuit by resistance R13; Electric capacity C6 is provided with between pin ISP and pin ISN.
3. a kind of LED lamp protective circuit according to claim 1, is characterized in that: described external power source VCC is successively by being connected with the drain electrode of metal-oxide-semiconductor Q2 after reverse Xiao Te diode D2, magnetic bead FB1.
4. a kind of LED lamp protective circuit according to claim 1, is characterized in that: described thermistor NTC1 and LED lamp panel surface are affixed the temperature sensing LED lamp panel.
5. a kind of LED lamp protective circuit according to claim 1, is characterized in that: the model of described LED drive chip U2 is RT8475.
6. a kind of LED lamp protective circuit according to claim 1, is characterized in that: the resistance of described resistance R1 is 68K, and the resistance of resistance R2 is 10K, and the resistance of resistance R4 is 5.1K.
7. a kind of LED lamp protective circuit according to claim 1, is characterized in that: be provided with high-frequency diode between the negative electrode of controllable accurate source of stable pressure U1 and the anode of diode D1.
8. a kind of LED lamp protective circuit according to claim 1, is characterized in that: described voltage stabilizing didoe Z1 is 0.5W, 10V voltage-stabiliser tube; The resistance of resistance R3 is 10K.
9. a kind of LED lamp protective circuit according to claim 1, is characterized in that: described LED connecting circuit joins branch road by some LED strip parallel with one another and is formed by connecting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510686912.3A CN105338694B (en) | 2015-10-22 | 2015-10-22 | A kind of LED lamp protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510686912.3A CN105338694B (en) | 2015-10-22 | 2015-10-22 | A kind of LED lamp protection circuit |
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| CN105338694A true CN105338694A (en) | 2016-02-17 |
| CN105338694B CN105338694B (en) | 2018-09-14 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107489993A (en) * | 2017-09-29 | 2017-12-19 | 江门市创亚照明电器有限公司 | A kind of heat-dissipating casing with tilting fin |
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2015
- 2015-10-22 CN CN201510686912.3A patent/CN105338694B/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107489993A (en) * | 2017-09-29 | 2017-12-19 | 江门市创亚照明电器有限公司 | A kind of heat-dissipating casing with tilting fin |
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| CN105338694B (en) | 2018-09-14 |
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