CN202602979U - A kind of LED driving power supply circuit - Google Patents

Abstract

The utility model discloses an LED driving power supply circuit, including an input power rectification circuit, a main control circuit, a transformer circuit, and a load driving circuit. The main control circuit and the transformer circuit are connected to the input power rectification circuit respectively. The main control circuit includes an LED dimming driving chip for LED dimming control and an RC frequency correction circuit for adjusting the working frequency of the LED dimming driving chip. The RC frequency correction circuit is connected to the LED dimming driving chip. The pulse width modulation signal output end of the LED dimming driving chip is connected to another power input end of the transformer circuit. The voltage output end of the transformer circuit is connected to the input end of the load driving circuit. The output end of the load driving circuit is connected to a load LED. The purpose of the utility model is to provide an LED driving power supply circuit for adjusting the brightness of a load LED without flickering.

Description

A kind of LED driving power supply circuit

[technical field]

The utility model relates to an LED driving power supply circuit.

[Background technique]

LED lighting has become a mainstream technology, and various countries are promoting LED lamps to replace incandescent and fluorescent lamps in mains-powered residential, commercial and industrial applications. The energy savings achieved by switching to energy-efficient LED lighting can be staggering. In China alone, according to government estimates, if one-third of the lighting market is switched to LED products, they will save 100 million kilowatt-hours of electricity per year and reduce 29 million tons of carbon dioxide emissions. However, different lighting locations and different public places have different lighting demand standards. For example, in store lighting, bright food can stimulate appetite; jewelry, clocks, clothing, etc. have bright illumination to stimulate the desire to buy; color printing, galleries, museums, consultation rooms, etc. The lighting of classrooms, factories, production lines, etc. requires non-glare but sufficient lighting brightness, so the brightness should be adjusted according to actual needs. Good lighting design not only saves energy and electricity, but also meets environmental protection requirements.

Incandescent lamps are easily dimmed using simple, low-cost leading-edge triac dimmers that are ubiquitous, but solid-state lighting replacement lamps must be able to use existing LEDs if they are to be truly successful. The controller and circuit realize dimming. When trying to adjust the brightness of LED lights, there are often problems of unstable operation and flickering. It is difficult to control the dimming of LED lights well. Therefore, it is necessary to solve the above problems .

[utility model content]

The utility model overcomes the shortcomings of the above-mentioned technologies, and provides a device that can control the turn-on time of the transformer and adjust the working frequency of the whole machine through the chip to realize the flicker-free light-emitting drive of the LED lamp, and realize the control of the LED lamp by cooperating with the thyristor dimmer. LED drive power supply circuit for load LED brightness adjustment.

In order to achieve the above object, the utility model adopts the following technical solutions:

A kind of LED driving power supply circuit, comprises input power rectification circuit 1, main control circuit 3, transformer circuit 4, and load drive circuit 5, a power input terminal of described main control circuit 3, transformer circuit 4 is rectified with input power respectively The circuit 1 is connected, the main control circuit 3 includes an LED dimming driver chip 31 for LED dimming control and an RC frequency effect circuit 32 for adjusting the operating frequency of the LED dimming driver chip 31, and the RC frequency effector The circuit 32 is connected to the LED dimming driver chip 31, the pulse width modulation signal output terminal of the LED dimming driver chip 31 is connected to the other power input terminal of the transformer circuit 4, and the voltage output terminal of the transformer circuit 4 is connected to the load driving The input end of the circuit 5 is connected, and the output end of the load driving circuit 5 is connected with a load LED.

A current detection circuit 2 is connected between the input power rectification circuit 1 and the main control circuit 3 , and the output terminal of the current detection circuit 2 is connected to an LED dimming driver chip 31 .

The current detection circuit 2 includes a triode Q1, the base and the emitter of the triode Q1 are used as two signal input detection terminals of the current detection circuit 2 and respectively connected to the two output terminals of the input power rectification circuit 1, and the triode Q1 The collector of the current detection circuit 2 is connected to the LED dimming drive chip 31 as the signal output terminal.

The transformer circuit 4 includes a transformer T1, one input end of the transformer T1 is connected to the input power rectifying circuit 1, the other input end of the transformer circuit 4 is connected to the signal output control end of the LED dimming driver chip 31, and the transformer T1 The first secondary output winding N4 of T1 is connected to the load drive circuit 5, the second secondary output winding N3 of the transformer T1 is connected to the LED dimming drive chip 31, and a capacitor is connected to the second secondary output winding N3 .

The load driving circuit 5 is also connected with an optocoupler 51 for feeding back the output voltage of the load driving circuit 5 to the LED dimming driving chip 31 , and the output terminal of the optocoupler 51 is connected to the LED dimming driving chip 31 .

The model of the LED dimming driver chip 31 is ssl2102t.

The beneficial effects of the utility model are: 1. The operating frequency of the LED dimming drive chip is adjusted by the RC frequency effect positive circuit, and the LED dimming drive chip outputs a pulse width modulation signal to control the conduction of the transformer, thereby realizing the adjustment of the output current and voltage, Realize flicker-free dimming control of LED loads, and achieve the purpose of dimming and energy saving of the utility model. 2. Through the detection of the current detection circuit, when the input current is too large, the LED dimming driver chip controls the conduction of the transformer circuit to ensure the stability of the work. 3. Combined with the real-time voltage feedback of the load drive circuit to the LED dimming drive chip, the overvoltage protection of the load LED is realized. 4. The auxiliary power supply circuit of the LED dimming driver chip is designed through the transformer circuit, which can improve the energy utilization rate. 5. It can be compatible and used with thyristor dimmers, and the control is simple and convenient.

[Description of drawings]

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

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

[Detailed ways]

Below in conjunction with accompanying drawing and embodiment of the present utility model, further describe in detail:

Referring to Fig. 1-2, an LED driving power supply circuit includes an input power rectification circuit 1, a main control circuit 3, a transformer circuit 4, and a load driving circuit 5, one of the main control circuit 3 and the transformer circuit 4 The power input terminals are respectively connected to the input power rectification circuit 1, and the main control circuit 3 includes an LED dimming driver chip 31 for LED dimming control and an RC frequency effect circuit for adjusting the working frequency of the LED dimming driver chip 31 32. The RC frequency effect circuit 32 is connected to the LED dimming driver chip 31, the pulse width modulation signal output terminal of the LED dimming driver chip 31 is connected to the other power input terminal of the transformer circuit 4, and the transformer circuit The voltage output terminal of 4 is connected with the input terminal of the load driving circuit 5, and the output terminal of the load driving circuit 5 is connected with a load LED.

The input power rectification circuit 1 includes a rectification circuit composed of a fuse F1, resistors R1-R4, R9-R13, R17, capacitor C1, electrolytic capacitors C2, C7, and diodes D1-D5.

The LED dimming driver chip 31 is connected with an RC frequency effect circuit 32 for adjusting its operating frequency so that the load LED does not flicker and emit light. The model of the LED dimming driver chip 31 is ssl2102t, and the RC frequency effect circuit 32 includes resistors R14-R15, capacitors C8-C9, the resistors R14, capacitors C8, and capacitors C9 are connected in parallel, one connection point is grounded, and the other connection point is connected to the frequency setting terminal of the LED dimming drive chip 31, The other connection point is also connected to the other frequency setting terminal of the LED dimming drive chip 31 through the resistor R15. The control signal output end of the LED dimming drive chip 31 is connected to an input end of the transformer circuit 4. When the thyristor dimmer adjusts the brightness of the LED, the frequency may be insufficient to produce LED flickering. Through the RC frequency effect circuit 32, adjust The operating frequency of the LED dimming driver chip 31 realizes flicker-free light emission.

The output end of the input power rectification circuit 1 is also connected with a current detection circuit 2 , and the output end of the current detection circuit 2 is connected with the current sensing input end of the LED dimming drive chip 31 . The current detection circuit 2 includes a triode Q1, resistors R22-R27, capacitor C12, electrolytic capacitor C11, voltage regulator tube D12, and the base of the triode Q1 is used as an input terminal of the current detection circuit 2 through the resistor R22 It is connected to the positive output terminal VACT of the input power rectification circuit 1, the emitter of the triode Q1 is used as another input terminal, and it is connected to the negative output terminal RGND of the input power rectification circuit 1 through the resistor R23, and the collector of the triode Q1 is used as the signal output terminal It is connected to the current sensing input terminal of the LED dimming driver chip 31 through the resistor R26. When the voltage between the two input terminals VACTR and RGND of the current detection circuit 2 is less than the conduction voltage of the transistor Q1, no current flows through the collector of the transistor Q1. However, when the voltage between VACTR and RGND exceeds the turn-on voltage of the transistor Q1, the transistor Q1 is turned on, and the collector of the transistor Q1 outputs a signal to the LED dimming driver chip 31, and the LED dimming driver chip 31 controls the conduction of the transformer circuit 4. Through, to achieve precision current control dimming energy saving function.

The transformer circuit 4 includes a transformer T1, a voltage regulator tube D6, and a diode D7. One input terminal of the primary winding of the transformer T1 is connected to the positive output terminal of the input power rectifier circuit 1, and the other input terminal of the primary winding of the transformer T1 is connected to the LED dimming terminal. The drive chip 31 is connected, the two output terminals of the first secondary output winding N4 of the transformer T1 are connected with the load drive circuit 5, the second secondary output winding N3 of the transformer T1 is used as the auxiliary power supply of the LED dimming drive chip 31, and it passes through the resistor R20 and diode D10 are connected to the pin VCC of the LED dimming driver chip 31. When the voltage on the pin VCC exceeds the startup level of the LED dimming driver chip 31, the LED dimming driver chip 31 immediately performs power supply switching to achieve high efficiency. Work.

The load drive circuit 5 includes a LED drive circuit composed of D8, C4, R8, R7, D9, and R28 for rectifying, filtering, and stabilizing voltage. For the optocoupler 51 of the LED dimming driver chip 31, the model of the optocoupler 51 is EL817, and the triode collector of the optocoupler 51 is used as the feedback output terminal of the load drive circuit 5, which is input to the PWM limit of the LED dimming driver chip 31 Pin connection, through the feedback signal, the LED dimming driver chip 31 adjusts the working state of the whole machine, controls the conduction time of the transformer T1, and performs overvoltage protection for the load LED to achieve more precise control.

Claims (6)

1. A kind of LED drive power supply circuit, it is characterized in that comprising input power rectification circuit (1), main control circuit (3), transformer circuit (4), and load drive circuit (5), described main control circuit (3) ), a power supply input terminal of the transformer circuit (4) is respectively connected with the input power rectification circuit (1), and the main control circuit (3) includes an LED dimming driver chip (31) for LED dimming control and for An RC frequency effect circuit (32) for adjusting the working frequency of the LED dimming drive chip (31), the RC frequency effect circuit (32) is connected to the LED dimming drive chip (31), and the LED dimming drive chip The pulse width modulation signal output terminal of (31) is connected with another power supply input terminal of the transformer circuit (4), and the voltage output terminal of the transformer circuit (4) is connected with the input terminal of the load driving circuit (5), and the load driving circuit (5) The output terminal is connected with a load LED. 2. A kind of energy-saving LED drive power supply circuit according to claim 1, characterized in that a current detection circuit (2) is connected between the input power rectification circuit (1) and the main control circuit (3), and the current The output end of the detection circuit (2) is connected to the LED dimming drive chip (31). 3. An energy-saving LED drive power supply circuit according to claim 2, characterized in that the current detection circuit (2) includes a triode Q1, and the base and emitter of the triode Q1 serve as the current detection circuit (2) The two signal input detection terminals of the current detection circuit (2) are respectively connected to the two output terminals of the input power rectification circuit (1), and the collector of the triode Q1 is connected to the LED dimming drive chip (31) as the signal output terminal of the current detection circuit (2). . 4. An energy-saving LED drive power supply circuit according to claim 1, characterized in that the transformer circuit (4) includes a transformer T1, an input terminal of the transformer T1 is connected to the input power rectifier circuit (1), and the transformer T1 The other input end of the circuit (4) is connected to the signal output control end of the LED dimming drive chip (31), the first secondary output winding N4 of the transformer T1 is connected to the load drive circuit (5), and the transformer T1 The second secondary output winding N3 of the second secondary output winding N3 is connected to the LED dimming drive chip (31), and a capacitor is connected to the second secondary output winding N3. 5. A kind of energy-saving LED drive power supply circuit according to claim 1, characterized in that the load drive circuit (5) is also connected with an output voltage for feeding back the load drive circuit (5) to the LED dimming drive chip ( 31) an optocoupler (51), the output end of the optocoupler (51) is connected to the LED dimming drive chip (31). 6. An energy-saving LED driving power supply circuit according to claim 1, characterized in that the model of the LED dimming driving chip (31) is ssl2102t.

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