CN204836691U - Keep apart LED drive circuit - Google Patents

Abstract

The utility model discloses a keep apart LED drive circuit, including chip U1, chip U2, electric capacity C1, transformer T, controllable accurate steady voltage source VS and inductance L4, 220V alternating current one end is connected respectively to electric capacity C1 one end, electric capacity C5 and transformer T coil L1, the electric capacity C5 other end and chip U2 pin D are connected respectively to the transformer T coil L1 other end, chip U2 pin S connects electric capacity C2 respectively, electric capacity C8, the electric capacity C1 other end, the 220V alternating current other end, transformer T coil L3 and electric capacity C6, diode D4 negative pole and chip U1 pin 1 are connected respectively to the electric capacity C6 other end. The utility model discloses keep apart LED drive circuit adopts chip U2 to use as keeping apart to optimizing circuit structure, making circuit structure simpler, with low costs, the interference killing feature is strong, and diode D1 and D2 constitute a clamp circuit, can arrive safe value because of the spike voltage clamper that the leakage inductance produced with inductance L4, and emitting diode LED both ends voltage is very stable, is fit for using widely.

Description

A kind of isolation LED drive circuit

Technical field

The utility model relates to a kind of LED, specifically a kind of isolation LED drive circuit.

Background technology

In energy crisis and climate warming problem more and more serious today, energy-conservationly become social focus subject under discussion with environmental protection.LED gets more and more people's extensive concerning because of plurality of advantages such as it is efficient, energy-saving and environmental protection, life-span length, rich color, little, the resistance to flicker of volume, reliability are high, regulation and control are convenient, is considered to 21 century the most promising lighting source.Traditional incandescent lamp efficiency is low, power consumption is high; Fluorescent lamp power saving, but useful life is short, frangible, and there is mercury pollution in discarded object; There is the shortcomings such as efficiency is low, power consumption is high, the life-span is short, hazards of electromagnetic radiation in high-intensity gas discharge lamp; If current poor efficiency, the traditional lighting of highly energy-consuming can be replaced with LED illumination, current more and more urgent energy shortage and ecological deterioration problem can be alleviated undoubtedly.Due to voltage-current characteristic and the temperature characterisitic of LED self, make the susceptibility of LED to electric current be higher than susceptibility to voltage, therefore can not be powered directly to LED by traditional power supply.Therefore, make with LED the problem that first lighting source will solve driving, how to provide stability is high, cost is low LED power circuit to become the research direction of Ge great LED producer.

Utility model content

The purpose of this utility model is to provide a kind of isolation LED drive circuit, to solve the problem proposed in above-mentioned background technology.

For achieving the above object, the utility model provides following technical scheme:

A kind of isolation LED drive circuit, comprises chip U1, chip U2, electric capacity C1, transformer T, controllable accurate source of stable pressure VS and inductance L 4, described electric capacity C1 one end connects 220V alternating current one end respectively, electric capacity C5 and transformer T coil L1, the transformer T coil L1 other end connects the electric capacity C5 other end and chip U2 pin D respectively, and chip U2 pin S connects electric capacity C2 respectively, electric capacity C8, the electric capacity C1 other end, the 220V alternating current other end, transformer T coil L3 and electric capacity C6, the electric capacity C6 other end connects diode D4 negative pole and chip U1 pin 1, the diode D4 positive pole connection transformer T coil L3 other end respectively, and chip U1 pin 2 connects the electric capacity C8 other end respectively, resistance R1 and chip U2 pin C, the resistance R1 other end connects the electric capacity C2 other end, described chip U1 pin 4 contact resistance R2, the resistance R2 other end connects the K pole of electric capacity C7 and controllable accurate source of stable pressure VS respectively, the electric capacity C7 other end connects the R pole of controllable accurate source of stable pressure VS, the A pole contact resistance R3 respectively of controllable accurate source of stable pressure VS, electric capacity C3, electric capacity C4, diode D2 positive pole, transformer T coil L2 and LED negative pole, the transformer T coil L2 other end connects diode D3 positive pole, and diode D3 negative pole connects the electric capacity C3 other end respectively, chip U1 pin 3 and inductance L 4, inductance L 4 other end is the contact resistance R3 other end respectively, the electric capacity C4 other end, diode D1 positive pole and LED positive pole, diode D1 negative pole connects diode D2 negative pole, and described chip U1 model is 4N25, and described chip U2 model is TOP414G.

As further program of the utility model: described controllable accurate source of stable pressure VS model is TL431.

As the utility model further scheme: described diode D2 is voltage stabilizing didoe.

Compared with prior art, the beneficial effects of the utility model are: the utility model isolation LED drive circuit adopts chip U2 to use as isolation, and optimized circuit structure, make circuit structure comparatively simple, cost is low, and antijamming capability is strong, diode D1 and D2 forms a clamp circuit, the peak voltage clamper that inductance L 4 can be produced because of leakage inductance is to safety value, and LED both end voltage is highly stable, is applicable to promoting the use of.

Accompanying drawing explanation

Fig. 1 is the circuit diagram of isolation LED drive circuit.

Embodiment

Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.

Refer to Fig. 1, in the utility model embodiment, a kind of isolation LED drive circuit, comprises chip U1, chip U2, electric capacity C1, transformer T, controllable accurate source of stable pressure VS and inductance L 4, electric capacity C1 one end connects 220V alternating current one end respectively, electric capacity C5 and transformer T coil L1, the transformer T coil L1 other end connects the electric capacity C5 other end and chip U2 pin D respectively, and chip U2 pin S connects electric capacity C2 respectively, electric capacity C8, the electric capacity C1 other end, the 220V alternating current other end, transformer T coil L3 and electric capacity C6, the electric capacity C6 other end connects diode D4 negative pole and chip U1 pin 1, the diode D4 positive pole connection transformer T coil L3 other end respectively, and chip U1 pin 2 connects the electric capacity C8 other end respectively, resistance R1 and chip U2 pin C, the resistance R1 other end connects the electric capacity C2 other end, chip U1 pin 4 contact resistance R2, the resistance R2 other end connects the K pole of electric capacity C7 and controllable accurate source of stable pressure VS respectively, the electric capacity C7 other end connects the R pole of controllable accurate source of stable pressure VS, the A pole contact resistance R3 respectively of controllable accurate source of stable pressure VS, electric capacity C3, electric capacity C4, diode D2 positive pole, transformer T coil L2 and LED negative pole, the transformer T coil L2 other end connects diode D3 positive pole, and diode D3 negative pole connects the electric capacity C3 other end respectively, chip U1 pin 3 and inductance L 4, inductance L 4 other end is the contact resistance R3 other end respectively, the electric capacity C4 other end, diode D1 positive pole and LED positive pole, diode D1 negative pole connects diode D2 negative pole, and chip U1 model is 4N25, and chip U2 model is TOP414G.

Controllable accurate source of stable pressure VS model is TL431.

Diode D2 is voltage stabilizing didoe.

Operation principle of the present utility model is: refer to Fig. 1, electric capacity C1 is input filter capacitor, resistance R1 is chip U2 control end resistance, electric capacity C2 is shunt capacitance, C8 in parallel between the C-S pin of chip U2 prevents from causing when High-frequency Interference appears in control end triggering power-down circuit misoperation, diode D3 is for exporting rectifier diode, the output filter that electric capacity C3, electric capacity C4, inductance L 4 are formed, electric capacity C4 is output de-noising electric capacity, diode D1 and D2 forms a clamp circuit, and the peak voltage clamper that inductance L 4 can be produced because of leakage inductance is to safety value; External error amplifier is made up of controllable accurate source of stable pressure TL431, when there is fluctuation in LED place voltage, sampling voltage is obtained after resistance R3 dividing potential drop, just compare with the reference voltage of TL431, produce an external control signal, change chip TOP414G control end electric current by chip 4N25 again, and then regulate duty ratio that voltage on LED is tended towards stability, the gain of control loop is set by resistance R2.

Claims (3)

1. isolate a LED drive circuit, comprise chip U1, chip U2, electric capacity C1, transformer T, controllable accurate source of stable pressure VS and inductance L 4, is characterized in that, described electric capacity C1 one end connects 220V alternating current one end respectively, electric capacity C5 and transformer T coil L1, the transformer T coil L1 other end connects the electric capacity C5 other end and chip U2 pin D respectively, and chip U2 pin S connects electric capacity C2 respectively, electric capacity C8, the electric capacity C1 other end, the 220V alternating current other end, transformer T coil L3 and electric capacity C6, the electric capacity C6 other end connects diode D4 negative pole and chip U1 pin 1, the diode D4 positive pole connection transformer T coil L3 other end respectively, and chip U1 pin 2 connects the electric capacity C8 other end respectively, resistance R1 and chip U2 pin C, the resistance R1 other end connects the electric capacity C2 other end, described chip U1 pin 4 contact resistance R2, the resistance R2 other end connects the K pole of electric capacity C7 and controllable accurate source of stable pressure VS respectively, the electric capacity C7 other end connects the R pole of controllable accurate source of stable pressure VS, the A pole contact resistance R3 respectively of controllable accurate source of stable pressure VS, electric capacity C3, electric capacity C4, diode D2 positive pole, transformer T coil L2 and LED negative pole, the transformer T coil L2 other end connects diode D3 positive pole, and diode D3 negative pole connects the electric capacity C3 other end respectively, chip U1 pin 3 and inductance L 4, inductance L 4 other end is the contact resistance R3 other end respectively, the electric capacity C4 other end, diode D1 positive pole and LED positive pole, diode D1 negative pole connects diode D2 negative pole, and described chip U1 model is 4N25, and described chip U2 model is TOP414G.

2. isolation LED drive circuit according to claim 1, is characterized in that, described controllable accurate source of stable pressure VS model is TL431.

3. isolation LED drive circuit according to claim 1, is characterized in that, described diode D2 is voltage stabilizing didoe.