CN203233578U - Light adjustable LED power supply - Google Patents

Abstract

The utility model discloses a light adjustable LED power supply which comprises a rectification filter module, a boost module, a light adjustment signal detection and transmission module and a buck constant current output module. An external power supply is input into the rectification filter module, undergoes rectification of the rectification filter module, is output to the boost module, undergoes boost of the boost module, is output to the buck constant current output module, undergoes constant current processing of the buck constant current output module, and is output to power an LED. The input end of the light adjustment signal detection and transmission module is connected with the rectification filter module, and the output end is connected with the buck constant current output module. According to the utility model, when the light adjustable LED power supply works, an electronic transformer is not impacted; in a simple and low cost mode, the detection and the transmission of a thyristor light adjustment signal are realized; and an analog signal can be accepted to carry out output current adjustment, so as to realize constant current output and output current adjustment.

Description

A dimmable LED power supply

technical field

The utility model discloses an LED power supply, in particular a dimmable LED power supply.

Background technique

Due to the advantages of high luminous efficiency, long service life, energy saving and environmental protection, LED has gradually replaced traditional incandescent lamps, tungsten halogen lamps, fluorescent tubes and cold cathode fluorescent lamps in recent years, and has been increasingly used in the lighting field and liquid crystal display backlight. Wide range of applications. Especially now, in the tide of environmental protection and energy saving, the upgrading of lighting products is also accelerating, such as incandescent lamps, halogen lamps, fluorescent lamps and other traditional lighting products have been replaced by LED products, and in this trend, MR16 halogen lamps The LEDization of LED has encountered relatively large technical difficulties. One is that it cannot be compatible with various electronic transformers, and the other is that it cannot be compatible with thyristor dimmers. Now for the compatibility of electronic transformers, many companies have proposed feasible solutions. As for the LED power supply of the dimmable MR16 lamp head, in recent years, major companies have invested a lot of manpower and material resources to develop this product. , but there has been no mature product production, and there is no breakthrough in low-power products below 10W.

Now various companies have two solutions for MR16 dimmable LED power supply: one is to design a dedicated chip to solve it, but the result is relatively high cost and the effect is not ideal. The second way is to use a programmable MCU chip to detect and process signals. The circuit is complicated, but the cost is high and the effect is average.

Contents of the invention

In view of the shortcomings of the above-mentioned adjustable LED power supply scheme in the prior art with complex structure and high cost, the utility model provides a new simple and low-cost circuit composed of a MR16 lamp head with a built-in dimmable LED power supply to realize The following two functional breakthroughs are made, one is compatible with various electronic transformers, and the other is compatible with general thyristor dimmers to achieve dimming.

The technical solution adopted by the utility model to solve the technical problem is: a dimmable LED power supply, the power supply includes a rectification filter module, a boost module, a dimming signal detection transmission module and a step-down constant current output module, and an external power supply input rectification filter The module is rectified by the rectifier and filter module and output to the boost module, and then output to the step-down constant current output module after being boosted by the step-up module, and then output to the LED power supply and dimming signal after constant current processing by the step-down constant current output module The input end of the detection transmission module is connected to the rectification and filtering module, and the output end is connected to the step-down constant current output module.

The technical solution adopted by the utility model to solve its technical problems further includes:

The rectification and filtering module includes a diode D1, a diode D2, a diode D3, a diode D4, and a filter capacitor C1. The diodes D1 to D4 are connected in the form of a bridge rectifier, and the filter capacitor C1 is connected between the output terminal of the bridge rectifier and the ground. .

The filter capacitor C1 is a ceramic capacitor.

The boost module includes a PFC chip U1, a switch tube Q1, a triode Q4, a boost inductor L1, a voltage regulator tube ZD1 and a voltage regulator tube ZD2, and the control signal output end of the PFC chip U1 is connected with a switch tube Q1, a switch tube Q1 and resistor R4 are connected in series between the DC bus and the negative DC line, the boost inductor L1 is connected in series to the DC bus, the diode D5 is connected in series to the DC bus of the rear stage of the switch tube Q1, and the common connection between the switch tube Q1 and the resistor R4 terminal is connected to the sixth pin of the PFC chip U1 through the resistor R9, the voltage regulator tube ZD1 and the resistor R10 are connected in series between the DC bus and the sixth pin of the PFC chip U1, and the resistor R5 is connected in series with the voltage regulator tube ZD2 in the DC Between the bus bar and the negative DC line, the base of the transistor Q4 is connected between the resistor R5 and the regulator ZD2, the collector of the transistor Q4 is connected to the DC bus, and the emitter of the transistor Q4 is connected to the negative DC line through the capacitor C3 .

The resistor R4 is connected in parallel with a resistor R3.

The step-down constant current output module includes a current detection chip U2, a power inductor L2 and a diode D7, the diode D7 and the power inductor L2 are connected in series on the DC bus, the other end of the power inductor L2 is the negative output terminal LB-, and the DC bus Resistor R8 is connected, resistor R8 is the positive output terminal LB+, the VIN terminal of the current detection chip U2 is connected to the DC bus, the ISEN terminal of the current detection chip U2 is connected to the positive output terminal LB+, and the LX terminal of the current detection chip U2 is connected to the On the common end of the diode D7 and the power inductor L2, the ADJ end of the current detection chip U2 is connected to the output end of the dimming signal detection transmission module.

The dimming signal detection transmission module includes a diode D6, a transistor Q2 and a transistor Q3, the diode D6 is connected to the output terminal of the rectification filter module, the diode D6, the resistor R6 and the resistor R11 are connected in series in sequence, and the resistor R11 is connected to the base of the transistor Q2. On the pole, the collector of the transistor Q2 is connected to the ADJ terminal of the current detection chip U2 through the resistor R14, the emitter of the transistor Q2 is connected to the negative DC line through the resistor R13, the base of the transistor Q3 is connected to the emitter of the transistor Q2, and the transistor The collector of Q2 is connected to the negative DC line, and the emitter of the triode Q2 is connected to the ADJ terminal of the current detection chip U2.

The beneficial effects of the utility model are: when the utility model is working, it will not cause impact on the electronic transformer; Signal to adjust the output current to achieve constant current output and adjust the output current.

The utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is a circuit block diagram of the utility model.

Fig. 2 is the schematic circuit diagram of the utility model.

Detailed ways

This embodiment is a preferred implementation mode of the present utility model. Others whose principle and basic structure are the same or similar to this embodiment are within the protection scope of the present utility model.

Please refer to accompanying drawings 1 and 2. The utility model mainly includes a rectification and filtering module, a boost module, a dimming signal detection transmission module and a step-down constant current output module. After that, it is output to the boost module, and then output to the step-down constant current output module after being boosted by the step-up module, and then output to the LED power supply after constant current processing by the step-down constant current output module. The dimming signal detection transmission module is connected to the step-down constant current output module to realize the purpose of dimming. The utility model uses a simple and low-cost circuit to form a built-in dimmable LED power supply for the MR16 lamp head, and realizes the following two functional breakthroughs. One is that the utility model is compatible with various electronic transformers, and the other is that it is compatible with general Silicon-controlled dimmers realize dimming. The utility model can be compatible with various electronic transformers with an output of 12V to drive LED loads within 10W, and can adjust the brightness of light through a general thyristor dimmer.

In this embodiment, the rectification and filtering module mainly includes a diode D1, a diode D2, a diode D3, a diode D4, and a filter capacitor C1. The diodes D1 to D4 are connected in the form of a bridge rectifier to rectify and high-frequency the high-frequency alternating current output by the electronic transformer. Frequency filtering to provide a pulsating DC power for the subsequent circuit. The filter capacitor C1 adopts a small-capacity ceramic capacitor, which will not cause impact on the electronic transformer.

In this embodiment, the working mode of the boost module is a control mode of fixed off-time and peak current detection, and its operating frequency will vary with the input voltage, so that the current on the boost inductor L1 will not be interrupted. Working in continuous mode, there will be power consumption in each working cycle of the electronic transformer, making the power supply a resistive load, so that the PF value of the electronic transformer can be as high as 0.9 or more during operation, and can adapt to general Triac dimmer for dimming. It can convert the pulsating direct current voltage of about 12V in the rectification and filtering part into a smoother direct current of 30V. The boost module mainly includes PFC chip U1, switch tube Q1, transistor Q4, boost inductor L1, voltage regulator tube ZD1 and voltage regulator tube ZD2. PFC chip U1 is the core part of the boost module, and the control signal output of PFC chip U1 The switch tube Q1 is connected to the terminal through the resistor R2, the switch tube Q1 and the resistor R4 are connected in series between the DC bus and the negative DC line, the resistor R3 is connected in parallel with the resistor R4, and the boost inductor L1 is connected in series on the DC bus. The diode D5 is connected in series to the DC bus of the rear stage of the switching tube Q1. The common end of the switching tube Q1 and the resistor R4 is connected to the sixth pin of the PFC chip U1 through the resistor R9, the regulator tube ZD1 and the resistor R10 are connected in series between the DC bus and the sixth pin of the PFC chip U1, and the resistor R5 and the sixth pin of the PFC chip U1 are connected in series. The Zener tube ZD2 is connected in series between the DC bus and the negative DC line, the base of the transistor Q4 is connected between the resistor R5 and the Zener tube ZD2, the collector of the transistor Q4 is connected to the DC bus, and the emitter of the transistor Q4 passes through Capacitor C3 is connected to the negative DC line.

In this embodiment, the step-down constant current output module can receive an analog signal to adjust the output current to realize constant current output and adjust the output current. The step-down constant current output module mainly includes a current detection chip U2, a power inductor L2 and a diode D7, the diode D7 and the power inductor L2 are connected in series on the DC bus, and the other end of the power inductor L2 is the negative output terminal LB- of the utility model, and A resistor R8 is connected to the bus, and the resistor R8 is the positive output terminal LB+ of the utility model. The VIN terminal of the current detection chip U2 is connected to the DC bus, and the ISEN terminal of the current detection chip U2 is connected to the positive output terminal LB+. The LX terminal of U2 is connected to the common terminal of the diode D7 and the power inductor L2, and the ADJ terminal of the current detection chip U2 is connected to the output terminal of the dimming signal detection transmission module. The step-down constant current output module receives the dimming signal to adjust the output current, and provides a stable output current for the LED.

In this embodiment, the dimming signal detection transmission module is used to detect the input average voltage, and an emitter follower circuit is used to transmit the voltage analog signal to the subsequent output constant current circuit to realize output current regulation. This part of the circuit uses a simple, low-cost The detection and transmission of the thyristor dimming signal are realized in a cost-effective way. This module part averages the input voltage and turns it into an analog voltage signal that can follow the phase angle of the dimmer, and then uses a simple emitter follower circuit to send this signal to the subsequent stage for output current regulation. This part mainly includes diode D6, transistor Q2 and transistor Q3. Diode D6 is connected to the output terminal of the rectifier filter module. Diode D6, resistor R6 and resistor R11 are connected in series in sequence. Resistor R11 is connected to the base of transistor Q2. The collector is connected to the ADJ terminal of the current detection chip U2 through the resistor R14, the emitter of the transistor Q2 is connected to the negative DC line through the resistor R13, the base of the transistor Q3 is connected to the emitter of the transistor Q2, and the collector of the transistor Q2 is connected to the The negative DC line, the emitter of the triode Q2 is connected to the ADJ terminal of the current detection chip U2.

Claims (7)

1. A dimmable LED power supply, characterized in that: the power supply includes a rectification and filtering module, a boost module, a dimming signal detection transmission module and a step-down constant current output module, and an external power supply is input to the rectification and filtering module. After being rectified by the filter module, it is output to the boost module, and then output to the step-down constant current output module after being boosted by the boost module, and then output to the LED power supply after constant current processing by the step-down constant current output module. The terminal is connected to the rectification and filtering module, and the output terminal is connected to the step-down constant current output module. 2. The dimmable LED power supply according to claim 1, characterized in that: said rectification and filtering module includes diode D1, diode D2, diode D3, diode D4 and filter capacitor C1, and diode D1 to diode D4 are connected to form a bridge In the form of a bridge rectifier, the filter capacitor C1 is connected between the output terminal of the bridge rectifier and the ground. 3. The dimmable LED power supply according to claim 2, wherein the filter capacitor C1 is a ceramic capacitor. 4. The dimmable LED power supply according to claim 1, characterized in that: the boost module includes a PFC chip U1, a switch tube Q1, a triode Q4, a boost inductor L1, a regulator tube ZD1 and a regulator tube ZD2, the switch tube Q1 is connected to the control signal output terminal of the PFC chip U1, the switch tube Q1 and the resistor R4 are connected in series between the DC bus and the negative DC line, the boost inductor L1 is connected in series to the DC bus, and the diode D5 is connected in series On the DC bus of the rear stage of the switching tube Q1, the common end of the switching tube Q1 and the resistor R4 is connected to the sixth pin of the PFC chip U1 through the resistor R9, and the regulator ZD1 and the resistor R10 are connected in series to the DC bus and the PFC chip U1 Between the sixth pin of the resistor R5 and the Zener tube ZD2 are connected in series between the DC bus and the negative DC line, the base of the transistor Q4 is connected between the resistor R5 and the Zener tube ZD2, and the collector of the transistor Q4 is connected to On the DC bus, the emitter of the transistor Q4 is connected to the negative DC line through the capacitor C3. 5. The dimmable LED power supply according to claim 4, characterized in that: the resistor R4 is connected in parallel with a resistor R3. 6. The dimmable LED power supply according to claim 1, characterized in that: the step-down constant current output module includes a current detection chip U2, a power inductor L2 and a diode D7, and the diode D7 and the power inductor L2 are connected in series On the DC bus, the other end of the power inductor L2 is the negative output terminal LB-, the resistor R8 is connected to the DC bus, and the resistor R8 is the positive output terminal LB+, the VIN terminal of the current detection chip U2 is connected to the DC bus, and the current detection chip U2 The ISEN terminal is connected to the positive output terminal LB+, the LX terminal of the current detection chip U2 is connected to the common terminal of the diode D7 and the power inductor L2, and the ADJ terminal of the current detection chip U2 is connected to the output terminal of the dimming signal detection transmission module. 7. The dimmable LED power supply according to claim 6, characterized in that: the dimming signal detection and transmission module includes a diode D6, a transistor Q2 and a transistor Q3, and the diode D6 is connected to the output end of the rectification and filtering module, The diode D6, the resistor R6 and the resistor R11 are connected in series in sequence, the resistor R11 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the ADJ terminal of the current detection chip U2 through the resistor R14, and the emitter of the transistor Q2 is connected to the The negative DC line, the base of the transistor Q3 is connected to the emitter of the transistor Q2, the collector of the transistor Q2 is connected to the negative DC line, and the emitter of the transistor Q2 is connected to the ADJ terminal of the current detection chip U2.

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