CN206498565U - A kind of LED drive power - Google Patents

Abstract

The utility model provides a kind of LED drive power, belongs to technical field of lamps.It solves existing technology and there is the problem of larger EMI is disturbed.This LED drive power includes EMI and controls circuit and the rectification filtering unit for controlling circuit to be connected with EMI successively, voltage conversion circuit and output filter circuit, PFC control circuit is also associated between voltage conversion circuit and rectification filtering unit, switch element is also associated between PFC control circuit and voltage conversion circuit, rectification filtering unit includes the bridge rectifier and filter capacitor CX2 being made up of four diodes, the inductance L2 and resistance R8 being connected in parallel are also associated between bridge rectifier and filter capacitor CX2, switch element includes FET Q1, the drain electrode of the FET Q1 is connected with voltage conversion circuit, grid and source electrode are connected with PFC control circuit respectively, electric capacity C11 is also associated between FET Q1 drain electrode and source electrode.This driving power supply can effectively reduce EMI values and EMI is suppressed in critical field.

Description

A LED drive power supply

technical field

The utility model belongs to the technical field of lamps and relates to an LED driving power supply.

Background technique

At present, there are many LED drive power products, most of which are based on IC control. Many IC companies at home and abroad have successively launched various IC circuits for drive power, most of which are economical and practical to compete for the market. Constant current type, constant voltage constant current hybrid type, low power factor PF: about 0.4-0.6, high harmonic content THD: greater than 100, LED drive with this kind of power, there will be electromagnetic interference (Electromagnetic Interference, EMI), output The current is not clean, the current ripple is high, and the voltage and current constant effect is poor, so that the LED cannot work in an ideal state. In addition, in the certification of LED drive power supply, conducted EMI is the difficulty of testing, and the problem of exceeding the standard is the most common. The fundamental reason for the conduction EMI of the LED drive power supply is the sudden change of current (di/dt) and sudden change of voltage (du/dt) in the circuit, which form conduction EMI through the coupling of wires, inductance and capacitance. When the rectifier and output diode of the LED drive power supply are forward-conducting, there is a large forward current flowing through them. When they are turned to cut-off by the reverse bias voltage, the reverse recovery current decreases sharply and a large di/dt occurs, which will produce a relatively large Strong high-frequency interference.

Existing conducted EMI noise suppression technology: The main disadvantage of passive filtering technology is that it is bulky and will cause a decrease in filtering performance when the noise source impedance and load impedance change. Active EMI filtering technology needs to detect signals and inject signals, and the circuit is complex , the reliability still needs to be further improved.

In view of the above existing problems, the existing Chinese patent literature discloses a light-emitting diode light source drive power supply [application number: CN201010551052.X], including EMI input suppression circuit, input rectification filter circuit, PFC and DC conversion power, IC auxiliary power supply Circuit, output rectification and filtering unit, constant voltage and constant current output feedback control circuit, EMI input suppression circuit is composed of CX1; L1; CX2; L2, the output electrical signal after filtering the grid clutter is connected to the input rectification and filtering circuit for rectification through C1 filtering; the rectified and filtered DC is connected to the isolation transformer; then connected to V1 in the PFC and DC conversion circuit, and connected to the IC auxiliary power supply circuit at the same time, coupled to the auxiliary line group through the isolation transformer for rectification and filtering, and then connected to PFC and DC The grid power factor correction chip IC1 in the DC conversion circuit supplies power to it. Although the invention can realize an LED drive power supply whose output voltage is adjusted according to the change of the load and the current is constant, the invention cannot suppress the EMI within the standard range during the EMI detection process, and there is a large EMI interference.

Contents of the invention

The purpose of the utility model is to solve the above-mentioned problems in the existing technology, and propose a LED driving power supply. The technical problem to be solved by the LED driving power supply is: how to effectively reduce the EMI value and suppress the EMI within the standard range.

The purpose of the utility model can be achieved through the following technical solutions: a LED drive power supply, including an EMI control circuit connected to the input end of an external power supply and a rectification filter unit, a voltage conversion circuit and an output filter circuit connected to the EMI control circuit in turn, The output terminal of the output filter circuit is connected to the LED module, a PFC control circuit is also connected between the voltage conversion circuit and the rectification filter unit, and a switch unit is also connected between the PFC control circuit and the voltage conversion circuit. The rectification filter unit includes a bridge rectifier circuit made up of four diodes D1, D2, D3, D4 and a filter capacitor CX2. One end of the filter capacitor CX2 is connected to the negative end of the diode D3, and the other end is grounded. It is characterized in that, An inductance L2 and a resistor R8 connected in parallel are also connected between the bridge rectifier circuit and the filter capacitor CX2, the switch unit includes a field effect transistor Q1, the drain of the field effect transistor Q1 is connected to the voltage conversion circuit, and the gate The pole and the source are respectively connected to the PFC control circuit, and a capacitor C11 is also connected between the drain and the source of the field effect transistor Q1.

The working principle of the LED drive power supply is: the input end of the EMI control circuit is connected to the input end of the external power supply, which is mainly used to suppress the noise of the power grid and the noise generated by itself, and eliminate the influence of the power grid on the LED drive power supply and the influence of the LED drive power supply on the power grid. , the output terminal of the EMI control circuit is connected to the positive terminals of diode D3 and diode D4 in the bridge rectifier circuit, the signal from the EMI control circuit is rectified and converted into DC, and then output after passing through the filter capacitor CX2, and the negative terminal of diode D3 Two parallel inductors L2 and resistor R8 are also connected between the extreme and the filter capacitor CX2, which are mainly used to limit the EMI peak current and suppress the EMI within the standard range. The voltage conversion circuit is connected with the rectification filter unit, the switch unit and the output filter circuit. It is used to receive the signal output by the rectifier filter unit, perform voltage conversion under the control of the switch unit, and output the converted voltage to the output filter circuit, and the output filter circuit drives the LED module to work; the voltage conversion circuit is connected to the PFC control circuit , used to provide a stable working power supply for the PFC control unit; the switch unit is connected to the PFC control circuit and the voltage conversion circuit respectively, and the switch unit is periodically turned on and off under the control of the control signal output by the PFC control circuit, thereby controlling the voltage For the voltage conversion of the conversion circuit, a capacitor C11 is connected in parallel to the switch unit, which can effectively reduce the EMI limit when detecting the EMI value, avoid EMI exceeding the standard, and ensure that the EMI value is within the standard range.

In the above-mentioned LED drive power supply, the PFC control circuit includes a PFC control chip U1 and a peripheral circuit, the peripheral circuit includes a resistor R10, and the DRV pin of the PFC control chip U1 is connected to the gate of the field effect transistor Q1 through the resistor R10 connection, the resistance R17 and the diode D6 are also connected between the resistor R10 and the gate of the field effect transistor Q1, the resistor R17 and the diode D6 are connected in parallel, and the positive end of the diode D6 is connected to the gate of the field effect transistor Q1 connected, the negative terminal is connected to the resistor R10, and the resistor R11 is also connected between the gate of the field effect transistor Q1 and the CS pin of the PFC control chip U1, and the source of the field effect transistor Q1 is also connected to two parallel-connected resistor R15 and resistor R16. Resistor R10 and resistor R17 are connected in series between the DRV pin of the PFC control chip U1 and the gate of the field effect transistor Q1 to limit the EMI peak current. The diode D6 connected in parallel to the resistor R17 adopts high-speed switching The diode is used to accelerate the turn-off time of the field effect transistor Q1, thereby reducing the intensity of EMI interference. The setting of the resistor R11 is used to make the work of the field effect transistor Q1 more stable. The source of the field effect transistor Q1 is connected with two resistors connected in parallel R15 and resistor R16 are used to make the circuit current constant.

In the above-mentioned LED driving power supply, the peripheral circuit further includes resistor R2, resistor R5, resistor R7, resistor R9, resistor R14, capacitor C8 and electrolytic capacitor C10, one end of resistor R2 is connected to filter capacitor CX2, and the other end is connected in series Resistor R5 and resistor R7 are connected to the VCC pin of the PFC control chip U1, the positive pole of the electrolytic capacitor C10 is connected to the VCC pin of the PFC control chip U1, the negative pole is connected to the GND pin of the PFC control chip U1, and the COMP of the PFC control chip U1 The feet are connected in series to the capacitor C8 and then grounded, the FB feet of the PFC control chip U1 are respectively connected to one end of the resistor R9 and the resistor R14, the other end of the resistor R9 is connected to the voltage conversion circuit, the other end of the resistor R14 is grounded, and the resistor R14 A capacitor C13 is also connected in parallel at both ends of the electrolytic capacitor C10, and a capacitor C9 is also connected in parallel at both ends of the electrolytic capacitor C10. The capacitor C13 is connected in parallel to the resistor R14, and the capacitor C9 is connected in parallel to both ends of the electrolytic capacitor C10, which can effectively filter out high-frequency interference, thereby reducing EMI more reliably, so that the EMI in the safety test will not exceed the standard.

In the above-mentioned LED driving power supply, the voltage conversion circuit includes a high-frequency transformer T3, and the high-frequency transformer T3 includes a primary winding N2, a first secondary winding N3, and a second secondary winding N4, and the input terminal of the primary winding N2 Pin 1 is connected to the rectifier filter unit, pin 2 of the output terminal is connected to the switch unit, the first secondary winding N3 is connected to the output filter circuit, the second secondary winding N4 provides working power to the PFC control unit through the diode D8, and the primary winding N2 and A high-frequency filter circuit and a diode D5 are also connected between the rectifier and filter units. The anode of the diode D5 is connected to the output terminal 2 of the primary winding, and the cathode of the diode D5 is connected to the high-frequency filter circuit. Diode D5 and high-frequency filter circuit are connected between high-frequency transformer T3 and rectifier filter unit, which can effectively eliminate high-frequency interference and reduce EMI value, so that EMI in safety test will not exceed the standard.

In the above LED driving power supply, the high frequency filter circuit includes a capacitor C3, a resistor R6 and a resistor R3 connected in parallel. In this LED driving power supply, the capacitor C3, the resistor R6 and the resistor R3 connected in parallel are used together with the diode D5, which can effectively eliminate high-frequency interference and reduce the EMI value.

In the above-mentioned LED drive power supply, the EMI control circuit includes a varistor TVR1, a capacitor C1, a capacitor C4, a resistor R20, a resistor R21 and a filter L4, and the resistor R20 and the resistor R21 are connected in series with the varistor TVR1 respectively. , capacitor C1, capacitor C4 and filter L4 are connected in parallel. The EMI control circuit is connected to the input terminal of the external power supply. It is used in the circuit of the LED drive power supply to suppress the noise of the power grid and the noise generated by itself, eliminate the influence of the power grid on the LED drive power supply and the influence of the LED drive power supply on the power grid, and improve the efficiency of the LED drive power supply. Anti-interference ability and system reliability. In addition, the varistor TVR1 is used to protect the LED drive power supply and LED from damage caused by the instantaneous increase of the grid voltage.

In the above-mentioned LED drive power supply, the output filter circuit includes a diode D7, a resistor R18, a resistor R19, a resistor R22, a capacitor C2 and an electrolytic capacitor C12, and the anode of the diode D7 is connected to the first secondary winding N3 of the high-frequency transformer T3 The output terminal 3 pins of the output end are connected, the negative pole is connected with the positive pole of the electrolytic capacitor C12, the negative pole of the electrolytic capacitor C12 is connected with the input terminal 4 pins of the first secondary winding N3, the resistor R18 and the capacitor C12 are connected in series with the diode D7, The resistor R19 is connected in parallel with the resistor R18, the resistor R22 is connected in parallel with both ends of the electrolytic capacitor C12, and the cathode of the diode D7 and the negative electrode of the electrolytic capacitor C12 lead to output terminals for connecting with the LED module. The output filter circuit is used to filter the voltage converted by the voltage conversion circuit, output it to the LED module and drive it to work, and the resistor R22 is used to protect the circuit.

Compared with the existing technology, this LED drive power supply precisely adjusts the output through the PFC control circuit to achieve the purpose of accurately adjusting the LED working current, adding inductance L2, capacitor C11, resistor R8, resistor R11, resistor R17, diode D6, diode D5 and high-frequency filter circuit can effectively reduce the EMI interference intensity, thereby effectively reducing the EMI value and suppressing the EMI within the standard range, so that the EMI in the safety test will not exceed the standard.

Description of drawings

Fig. 1 is a block diagram of the principle structure of the utility model.

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

In the figure, 1. EMI control circuit; 2. Rectification filter unit; 3. Voltage conversion circuit; 4. Output filter circuit; 5. PFC control circuit; 6. Switching unit; 7. LED module; 8. High frequency filter circuit ; 9, external power input.

detailed description

The following are specific embodiments of the utility model and in conjunction with the accompanying drawings, the technical solution of the utility model is further described, but the utility model is not limited to these embodiments.

As shown in Figure 1, the LED drive power supply includes an external power input terminal 9, an EMI control circuit 1, a rectification filter unit 2, a voltage conversion circuit 3, an output filter circuit 4, a PFC control circuit 5, a switch unit 6, and an LED module 7 And high-frequency filtering circuit 8, wherein, the input end of EMI control circuit 1 is connected with external power supply input end 9, and the output end is connected with the input end of rectification filter unit 2, is used for the signal rectification that EMI control circuit 1 transmits and converts into DC and output after filtering; the voltage conversion circuit 3 is connected to the rectification filter unit 2, the switch unit 6 and the output filter circuit 4 respectively, the LED module 7 is connected to the output filter circuit 4, and the voltage conversion circuit 3 is used to receive the rectification filter unit 2 The output signal is subjected to voltage conversion under the control of the switch unit 6, and the converted voltage is output to the output filter circuit 4, and after being filtered by the output filter circuit 4, the LED module 7 is driven to work, and the voltage conversion circuit 3 also communicates with the output filter circuit 4. The PFC control circuit 5 is connected to provide working power for the PFC control circuit 5. The PFC control circuit 5 is also connected to the rectification and filtering unit 2 to provide initial working power for the PFC control circuit 5. The PFC control circuit 5 is also connected to the switch unit 6. Connected to output control signal to control switch unit 6 to turn on and off periodically, and then control the voltage conversion of voltage conversion circuit 3; high frequency filter circuit 8 is connected between rectification filter unit 2 and voltage conversion circuit 3 .

As shown in Figure 2, the rectification and filtering unit 2 includes a bridge rectification circuit composed of diode D1, diode D2, diode D3, and diode D4 and a filter capacitor CX2, wherein the positive terminal of diode D3 and the positive terminal of diode D4 are used for The input terminal connected to the EMI control circuit 1, the positive terminal of the diode D1 and the negative terminal of the diode D3 lead to the output terminal for connection with the external circuit, one end of the filter capacitor CX2 is connected to the negative terminal of the diode D3, and the other end is grounded, the bridge An inductor L2 and a resistor R8 connected in parallel between the type rectifier circuit and the filter capacitor CX2 are mainly used to limit the EMI peak current, thereby suppressing the EMI within the standard range.

EMI control circuit 1 includes varistor TVR1, capacitor C1, capacitor C4, resistor R20, resistor R21 and filter L4, resistor R20 and resistor R21 are connected in parallel with varistor TVR1, capacitor C1, capacitor C4 and filter L4 after being connected in series connect. The EMI control circuit 1 is connected to the input terminal 9 of the external power supply, and is used in the circuit of the LED drive power supply to suppress grid noise and self-generated noise, eliminate the influence of the grid on the LED drive power supply and the impact of the LED drive power supply on the grid, and improve the LED drive power supply. The anti-interference ability of the power supply and the reliability of the system. In addition, the varistor TVR1 is used to protect the LED drive power supply and LED from damage caused by the instantaneous increase of the grid voltage.

The voltage conversion circuit 3 includes a high-frequency transformer T3, and the high-frequency transformer T3 includes a primary winding N2, a first secondary winding N3, and a second secondary winding N4. The input terminal 1 of the primary winding N2 is connected to the rectification and filtering unit 2, and the output terminal 2 It is connected to the switch unit 6, the first secondary winding N3 is connected to the output filter circuit 4, the second secondary winding N4 provides working power to the PFC control unit through the diode D8, and a high-frequency filter is also connected between the primary winding N2 and the rectification filter unit 2 The circuit 8 and the diode D5, the anode of the diode D5 is connected to the output terminal 2 of the original winding, and the cathode of the diode D5 is connected to the high frequency filter circuit 8. Among them, the high-frequency filter circuit 8 includes a capacitor C3, a resistor R6 and a resistor R3. After the capacitor C3, the resistor R6 and the resistor R3 are connected in parallel, one end is connected to the negative end of the diode D5, and the other end is respectively connected to the rectification filter unit 2 and the original winding N2. Input terminal 1 pin connection. Connecting the diode D5 and the high-frequency filter circuit 8 between the high-frequency transformer T3 and the rectifier filter unit 2 can effectively eliminate high-frequency interference and reduce the EMI value, so that the EMI in the safety test will not exceed the standard.

The switch unit 6 includes a field effect transistor Q1, the drain of the field effect transistor Q1 is connected to the output terminal 2 pin of the primary winding N2 of the high-frequency transformer T3, and the gate is connected to the DRV pin of the PFC control chip U1 through two series connection resistors R10 and R17 connection, the source is connected to the CS pin of the PFC control chip U1, the source is also connected to two parallel resistors R15 and R16 in series and then grounded, and a capacitor C11 is also connected between the drain and the source of the field effect transistor Q1, as a preferred , the resistor R17 is also connected in parallel with a diode D6, the positive terminal of the diode D6 is connected to the gate of the field effect transistor Q1, and the negative terminal is connected to the resistor R10, between the gate of the field effect transistor Q1 and the CS pin of the PFC control chip U1 A resistor R11 is also connected. Resistor R10 and resistor R17 are connected in series between the DRV pin of the PFC control chip U1 and the gate of the field effect transistor Q1 to limit the EMI peak current. The diode D6 connected in parallel to the resistor R17 adopts high-speed switching The diode is used to accelerate the turn-off time of the field effect transistor Q1, thereby reducing the intensity of EMI interference. The setting of the resistor R11 is used to make the work of the field effect transistor Q1 more stable. The source of the field effect transistor Q1 is connected with two resistors connected in parallel R15 and resistor R16 are used to make the circuit current constant. As another preferred solution, the switch unit 6 may also be a triode.

The PFC control circuit 5 includes a PFC control chip U1 and a peripheral circuit. The peripheral circuit includes a resistor R2, a resistor R5, a resistor R7, a resistor R9, a resistor R10, a resistor R14, a capacitor C8 and an electrolytic capacitor C10. One end of the resistor R2 is connected to the filter capacitor CX2 , the other end is connected to the VCC pin of the PFC control chip U1 in series with the resistor R5 and resistor R7 in sequence, the negative terminal of the diode D5 is connected to the VCC pin of the PFC control chip U1 after being connected in series with the resistor R7, and the positive pole of the electrolytic capacitor C10 is connected to the PFC control chip U1 The VCC pin of the chip U1 is connected, the negative pole is connected to the GND pin of the PFC control chip U1, and the two ends of the electrolytic capacitor C10 are also connected in parallel with the capacitor C9; the FB pin of the PFC control chip U1 is respectively connected to one end of the resistor R9 and the resistor R14, and the resistor R9 The other end of the high-frequency transformer T3 is connected to the output terminal 6 of the second secondary winding N4, the other end of the resistor R14 is grounded, the two ends of the resistor R14 are connected in parallel with a capacitor C13, and the COMP pin of the PFC control chip U1 is connected in series with the capacitor C8 back to ground. Among them, the PFC control chip U1 can choose LZC8120. The capacitor C13 is connected in parallel to the resistor R14, and the capacitor C9 is connected in parallel to both ends of the electrolytic capacitor C10, which can effectively filter out high-frequency interference, thereby reducing EMI more reliably, so that the EMI in the safety test will not exceed the standard.

The output filter circuit 4 includes a diode D7, a resistor R18, a resistor R19, a resistor R22, a capacitor C2 and an electrolytic capacitor C12. The positive pole of the diode D7 is connected to the output terminal 3 of the first secondary winding N3 in the high-frequency transformer, and the negative pole is connected to the electrolytic capacitor C12. The positive pole of the electrolytic capacitor C12 is connected to the input terminal 4 of the first secondary winding N3, then the capacitor CY12 is connected in series, and then connected to the diode D7, the resistor R18 and the capacitor C12 are connected in series, and the resistor R19 is connected in parallel with the resistor R18. The two ends of the electrolytic capacitor C12 are connected in parallel, and the negative electrodes of the diode D7 and the negative electrode of the electrolytic capacitor C12 respectively lead to output terminals for connecting with the LED module 7 . The output filter circuit 4 is used to filter the voltage converted by the voltage conversion circuit 3 and output it to the LED module 7 to drive it to work, wherein the resistor R22 is used to protect the circuit.

The working principle of the LED drive power supply is: the current of the input terminal 9 of the external power supply is sent to the input terminal of the EMI control circuit 1 for filtering through the fuse F1, and the filtered signal passes through a bridge composed of diode D1, diode D2, diode D3 and diode D4 Type rectification circuit rectification, inductance L2 and resistor R8 connected in parallel to limit EMI peak current and filter capacitor CX2 to provide initial power supply for PFC control chip U1, and output to input terminal 1 of primary winding N2 of high frequency transformer T3. The control signal generated by the PFC control chip U1 controls the field effect transistor Q1 to be turned on and off periodically through the DRV pin, so that a voltage signal is generated on the first secondary winding N3 and passed through the diode D7, the electrolytic capacitor C12, the capacitor C2, the resistor R18, The output filter circuit 4 composed of the resistor R19 and the resistor R22 is sent to both ends of the LED module 7 to provide working power for the LED module 7 . After the PFC control chip U1 works stably, the second secondary winding N4 of the high-frequency transformer T3 supplies power to the PFC control chip U1 through the diode D8 and the resistor R7. In addition, the CS pin and FB pin of the PFC control chip U1 also collect the high-frequency transformer The PFC control chip U1 adjusts the control signal according to the collected signal, and then achieves the purpose of accurately adjusting the LED working circuit. The capacitor C11 is connected in parallel to the source and drain of the field effect transistor Q1, which can reduce the EMI value when the frequency is between 20M-30M, and avoid the phenomenon that the EMI exceeds the standard during the detection process. The gate of the field effect transistor Q1 and The resistor R17, the resistor R11 and the diode D6 connected between the PFC control chip U1 can further reduce the electromagnetic interference of EMI and ensure that the EMI value can be suppressed within the standard range.

The specific embodiments described herein are only examples to illustrate the spirit of the present invention. Those skilled in the technical field to which the utility model belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the utility model or go beyond the appended claims defined range.

Claims (7)

1. A LED drive power supply, comprising an EMI control circuit (1) connected to an external power supply input terminal (9) and a rectification filter unit (2) connected to the EMI control circuit (1) in turn, a voltage conversion circuit (3) and an output filter circuit (4), the output end of the output filter circuit (4) is connected to the LED module (7), and a PFC control circuit is also connected between the voltage conversion circuit (3) and the rectification filter unit (2) circuit (5), a switching unit (6) is also connected between the PFC control circuit (5) and the voltage conversion circuit (3), and the rectification and filtering unit (2) includes four diodes D1, D2, D3, A bridge rectifier circuit composed of D4 and a filter capacitor CX2, one end of the filter capacitor CX2 is connected to the negative terminal of the diode D3, and the other end is grounded, and it is characterized in that a bridge rectifier circuit is also connected to the filter capacitor CX2. Inductance L2 and resistor R8 connected in parallel, the switch unit (6) includes a field effect transistor Q1, the drain of the field effect transistor Q1 is connected to the voltage conversion circuit (3), and the gate and source are respectively connected to the PFC control circuit (5) Connection, a capacitor C11 is also connected between the drain and the source of the field effect transistor Q1. 2. The LED drive power supply according to claim 1, wherein the PFC control circuit (5) comprises a PFC control chip U1 and a peripheral circuit, the peripheral circuit comprises a resistor R10, and the DRV of the PFC control chip U1 The pin is connected to the gate of the field effect transistor Q1 through the resistor R10, and a resistor R17 and a diode D6 are also connected between the resistor R10 and the gate of the field effect transistor Q1, and the resistor R17 and the diode D6 are connected in parallel, and the diode The positive terminal of D6 is connected to the gate of the field effect transistor Q1, and the negative terminal is connected to the resistor R10. A resistor R11 is also connected between the gate of the field effect transistor Q1 and the CS pin of the PFC control chip U1. The source of the tube Q1 is also connected to two resistors R15 and R16 connected in parallel. 3. The LED driving power supply according to claim 2, characterized in that, the peripheral circuit also includes resistor R2, resistor R5, resistor R7, resistor R9, resistor R14, capacitor C8 and electrolytic capacitor C10, one end of resistor R2 is connected to The filter capacitor CX2 is connected, and the other end is connected to the VCC pin of the PFC control chip U1 in series with the resistor R5 and the resistor R7 in sequence. The positive pole of the electrolytic capacitor C10 is connected to the VCC pin of the PFC control chip U1, and the negative pole is connected to the GND pin of the PFC control chip U1. , the COMP pin of the PFC control chip U1 is connected in series with the capacitor C8 and grounded, the FB pin of the PFC control chip U1 is connected to one end of the resistor R9 and the resistor R14 respectively, and the other end of the resistor R9 is connected to the voltage conversion circuit (3) , the other end of the resistor R14 is grounded, a capacitor C13 is connected in parallel to both ends of the resistor R14, and a capacitor C9 is connected in parallel to both ends of the electrolytic capacitor C10. 4. The LED driving power supply according to claim 1, characterized in that, the voltage conversion circuit (3) includes a high-frequency transformer T3, and the high-frequency transformer T3 includes a primary winding N2, a first secondary winding N3 and a second The secondary winding N4, the input pin 1 of the primary winding N2 is connected to the rectification filter unit (2), the output pin 2 is connected to the switch unit (6), the first secondary winding N3 is connected to the output filter circuit (4), and the second The secondary winding N4 provides operating power to the PFC control unit through a diode D8, and a high-frequency filter circuit (8) and a diode D5 are also connected between the primary winding N2 and the rectifying filter unit (2), and the anode of the diode D5 is connected to the diode D5. The output end of the original winding is connected to pin 2, and the cathode of the diode D5 is connected to the high-frequency filter circuit (8). 5. The LED driving power supply according to claim 4, characterized in that the high frequency filter circuit (8) comprises a capacitor C3, a resistor R6 and a resistor R3 connected in parallel. 6. The LED drive power supply according to claim 1, characterized in that, the EMI control circuit (1) comprises a varistor TVR1, a capacitor C1, a capacitor C4, a resistor R20, a resistor R21 and a filter L4, and the resistor R20 and resistor R21 are connected in parallel with varistor TVR1 , capacitor C1 , capacitor C4 and filter L4 after being connected in series. 7. The LED drive power supply according to claim 4, characterized in that, the output filter circuit (4) comprises a diode D7, a resistor R18, a resistor R19, a resistor R22, a capacitor C2 and an electrolytic capacitor C12, the diode D7 The positive pole is connected to pin 3 of the output terminal of the first secondary winding N3 in the high-frequency transformer T3, and the negative pole is connected to the positive pole of the electrolytic capacitor C12, and the negative pole of the electrolytic capacitor C12 is connected to pin 4 of the input terminal of the first secondary winding N3. The resistor R18 and the capacitor C12 are connected in series to the diode D7, the resistor R19 is connected in parallel with the resistor R18, the resistor R22 is connected in parallel at both ends of the electrolytic capacitor C12, and the negative pole of the diode D7 and the negative pole of the electrolytic capacitor C12 are respectively drawn out Output terminal for connecting with the LED module (7).