LED driver

Abstract

The present invention discloses an LED driver, including: a PFC main circuit, a drive control circuit, an isolation circuit, a voltage regulation circuit, a frequency control drive circuit, a current regulation circuit and a resonant DC-DC circuit, wherein the PFC main circuit is connected to the resonant DC-DC circuit, the resonant DC-DC circuit is respectively connected to the input end of the current regulation circuit and the input end of the voltage regulation circuit, the output end of the current regulation circuit is connected to the input end of the frequency control drive circuit, the output end of the frequency control drive circuit is connected to the resonant DC-DC circuit, the output end of the voltage regulation circuit is connected to the input end of the drive control circuit via the isolation circuit, and the output end of the drive control circuit is connected to the PFC main circuit. The present invention realizes the multi-channel output of the LED driver through different coupling coefficients between the two secondary windings of the transformer and the primary winding, and realizes that the multi-channel output of an LED has both constant voltage output and constant current output through the voltage regulation circuit and the current regulation circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of lighting equipment, and in particular to an LED driver. Background Art

[0002] LED is widely used in the field of lighting due to its advantages of energy saving, environmental protection, long life and high conversion efficiency. LED drivers convert input voltage into direct current and supply it to LED loads. Currently, there are two types of LED drivers, one is a constant current LED driver and the other is a constant voltage LED driver. In some lighting occasions, the same driver needs to drive two loads at the same time. The existing LED drivers can have two or more outputs, but the multiple outputs of the same driver are all of the same type, that is, the same driver has multiple constant current outputs or multiple constant voltage outputs, but it is not possible to achieve both constant current output and constant voltage output in the multiple outputs of the same driver.

[0003] For example, a "constant voltage and constant current driver for high-power LED spotlights" disclosed in Chinese patent documents, with publication number CN201467519U and publication date May 12, 2010, includes a power input terminal, a rectifier circuit connected to the power input terminal, a switch transformer connected to the rectifier circuit, and an output terminal connected to the switch transformer for connecting a load LED, characterized in that it also includes a PFC circuit, a power drive constant voltage circuit and a constant current circuit, the PFC circuit is arranged between the rectifier circuit and the switch transformer, the power drive constant voltage circuit includes a power drive circuit and a constant voltage control circuit, the power drive circuit is arranged between the PFC circuit and the switch transformer, the constant voltage control circuit collects the output signal of the switch transformer and generates a feedback signal to the power drive circuit, and a constant current circuit is arranged between the switch transformer and the output terminal. The constant voltage and constant current output of the LED driver is realized by the constant current circuit and the constant voltage current, but the LED driver of the invention can still only realize constant voltage or constant current output, and cannot realize that the multi-channel output of the same driver has both constant current output and constant voltage output. Summary of the invention

[0004] The present invention mainly solves the problem that the existing LED driver cannot realize the simultaneous output of constant voltage and constant current by providing an LED driver, which can achieve both constant current output and constant voltage output in the multi-channel output of the same driver through constant voltage and constant current detection and regulation.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions: an LED driver, comprising a PFC main circuit, a drive control circuit, an isolation circuit, a voltage regulation circuit, a frequency control drive circuit, a current regulation circuit and a resonant DC-DC circuit, wherein the input end of the PFC main circuit serves as the input end of the LED driver and is used to connect a power supply, the output end of the PFC main circuit is connected to the input end of the resonant DC-DC circuit, the output end of the resonant DC-DC circuit comprises a constant voltage output end and a constant current output end, the input end of the current regulation circuit is connected to the constant current output end, the output end of the current regulation circuit is connected to the frequency control drive circuit, and the current regulation circuit is used to detect the current outputted by the constant current output end and A first feedback signal is output to the frequency control driving circuit, and the frequency control driving circuit outputs the first driving signal to the resonant DC-DC circuit according to the size of the first feedback signal, and the current output by the constant current output end is maintained constant through the working frequency of the resonant DC-DC circuit. The input end of the voltage regulating circuit is connected to the constant voltage output end, and the output end of the voltage regulating circuit is connected to the driving control circuit via an isolation circuit. The voltage regulating circuit is used to detect the voltage output by the constant voltage output end and output a second feedback signal to the driving control circuit through the isolation circuit. The driving control circuit outputs a second driving signal to the PFC main circuit according to the size of the second feedback signal to make its output voltage constant, thereby making the voltage of the constant voltage output end constant. The power supply is connected through the input end of the PFC main circuit, and the power is output to the resonant DC-DC circuit after being boosted by the PFC circuit. The resonant DC-DC circuit performs constant voltage and constant current output. The voltage regulation circuit performs constant voltage detection on the voltage output by the resonant DC-DC circuit and feeds back the detection result to the drive control circuit. The output voltage of the PFC main circuit is adjusted by the drive control circuit to achieve constant voltage output. The current regulation circuit performs constant current detection on the current output by the resonant DC-DC circuit and feeds back the detection result to the frequency control drive circuit. The output current of the resonant DC-DC circuit is adjusted by the frequency control drive circuit to achieve constant current output. Both constant voltage output and constant current output are achieved in multiple outputs through one LED driver.

[0006] Preferably, the PFC main circuit comprises an inductor L, a switch tube S0, a diode D1 and a capacitor C0, one end of the inductor L is connected to the positive electrode of the power supply, the other end of the inductor L is respectively connected to one end of the switch tube S0 and the anode of the diode D1, the other end of the switch tube S0 is respectively connected to one end of the capacitor C0 and the negative electrode of the power supply, the other end of the capacitor C0 is connected to the cathode of the diode D1, and the two ends of the capacitor C0 are also connected to the resonant DC-DC circuit as the output end of the PFC main circuit. The current passes through the inductor L to prevent the high-voltage interference signal from damaging the circuit, and the voltage stored at the two ends of the capacitor C0 is controlled by the switch tube S0 to realize the control and regulation of the output voltage Vbus of the PFC main circuit, and the diode D1 prevents the current from flowing back into the switch tube S0.

[0007] Preferably, the resonant DC-DC circuit further comprises a switch unit, a resonant capacitor Cr and a transformer, wherein the transformer comprises a primary winding N1, a secondary winding M1 and a secondary winding M2, wherein the primary winding N1 and the resonant capacitor Cr are connected in series and then connected to the switch unit, and the other two ends of the switch unit serve as input ends of the resonant DC-DC circuit; the secondary winding M1 serves as a constant voltage output end through a first rectified output end after rectification, and the secondary winding M2 serves as a constant current output end through a second rectified output end after rectification. The secondary winding M1 and the secondary winding M2 are transformed by a transformer, so that the circuit generates two outputs.

[0008] Preferably, the coupling coefficient between the secondary winding M1 and the primary winding N1 is greater than the coupling coefficient between the secondary winding M2 and the primary winding N1. According to the different coupling coefficients between the secondary winding M1 and the secondary winding M2 and the primary winding N1, the resonant DC-DC circuit generates multiple different outputs.

[0009] Preferably, the switch unit in the resonant DC-DC circuit includes a switch tube S1 and a switch tube S2; the resonant DC-DC circuit also includes a diode D2, a diode D3, a diode D4, a diode D5, a capacitor C1, a capacitor C2 and a resistor Rs, the first end of the switch tube S1 serves as the positive input end of the resonant DC-DC circuit, the second end of the switch tube S1 is respectively connected to the first end of the switch tube S2 and one end of the primary winding N1, the second end of the switch tube S2 serves as the negative input end of the resonant DC-DC circuit and is connected to one end of the resonant capacitor Cr, the other end of the resonant capacitor Cr is connected to the other end of the primary winding N1, the secondary winding M1 and the secondary winding M2 have tap ends, and the first end of the secondary winding M1 The first end of the secondary winding M2 is connected to the anode of the diode D4, the second end of the secondary winding M2 is connected to the anode of the diode D2 via the diode D3, the cathode of the diode D2 and the tap end of the secondary winding M1 are connected to the capacitor C1, and the two ends of the capacitor C1 serve as the constant voltage output ends; the first end of the secondary winding M2 is connected to the anode of the diode D4, the second end of the secondary winding M2 is connected to the anode of the diode D4 via the diode D5, the cathode of the diode D4 is connected to the first end of the capacitor C2, the tap end of the secondary winding M2 is respectively connected to the second end of the capacitor C2 and the first end of the resistor Rs, the two ends of the capacitor C2 serve as the constant current output ends, and the second end of the resistor Rs is connected to the current regulating circuit. The switch tube S1, the switch tube S2, the resonant capacitor Cr, the diode D2, the diode D3, the diode D4, the diode D5 and the transformer form an LLC half-bridge resonant circuit, which converts the direct current output by the PFC main circuit into alternating current, and performs voltage conversion through the transformer. The coupling coefficients of the two secondary windings of the transformer and the primary winding are different, so that the voltage and current output by the resonant DC-DC circuit are different, and the output power of most outputs is different. After the voltage is transformed by the transformer, the half-bridge rectifier composed of the diode D2, the diode D3, the diode D4 and the diode D5 converts the alternating current into direct current, and after being stabilized by the capacitors C1 and C2, it supplies power to the LED lamp.

[0010] Preferably, the voltage regulation circuit comprises an operational amplifier U1, a resistor R1, a resistor R2, a resistor R3 and a capacitor C4, the negative phase input terminal of the operational amplifier U1 is respectively connected to the first end of the capacitor C4, one end of the resistor R1 and one end of the resistor R2, the other end of the resistor R1 is connected to the first end of the capacitor C1, the other end of the resistor R2 is connected to the second end of the capacitor C1, the second end of the capacitor C4 is connected to the output terminal of the operational amplifier U1 via the resistor R3, and the voltage reference signal Vref1 is input to the positive phase input terminal of the operational amplifier U1. The operational amplifier U1 compares the detected voltage signal with the voltage reference signal Vref1, and outputs a second feedback signal to the drive control circuit through the isolation circuit according to the comparison result, and the capacitor C1, the resistor R3 and the operational amplifier form a negative feedback regulation.

[0011] Preferably, the isolation circuit includes a photocoupler, the input end of the photocoupler is connected to the voltage regulating circuit, and the output end of the photocoupler is connected to the drive control circuit. The voltage regulating circuit and the drive control circuit are isolated by the photocoupler to prevent high-frequency signals from interfering with the circuit.

[0012] Preferably, the current regulating circuit comprises an operational amplifier U2, a capacitor C5 and a resistor R4, the negative phase input terminal of the operational amplifier U2 is respectively connected to the first end of the capacitor C5 and the second end of the resistor Rs, the second end of the capacitor C5 is connected to the output terminal of the operational amplifier U2 via the resistor R4, and the positive phase input terminal of the operational amplifier inputs the current reference signal Iref1. The detected current signal is compared with the current reference signal Iref1 by the operational amplifier U2, and a first feedback signal is output to the frequency control driving circuit according to the comparison result, and the operational amplifier U2, the capacitor C5 and the resistor R4 constitute negative feedback regulation.

[0013] Preferably, the frequency control driving circuit includes a resonance control chip, a voltage-controlled oscillator and a driving circuit. The voltage-controlled oscillator receives the first feedback signal transmitted by the current regulation circuit and determines the magnitude of the frequency of the switch tube S1 and the switch tube S2 according to the magnitude of the first feedback signal, and transmits the frequency signal to the resonance control chip. The resonance control chip generates a driving signal through the driving circuit according to the frequency signal and outputs it to the switch tube S1 and the switch tube S2. The resonance control chip receives the first feedback signal output by the current regulation circuit, and controls the conduction and cutoff of the MOS tube Q1 and the MOS tube Q2 according to the first feedback signal, so that the current output of the resonance DC-DC circuit is stable and consistent with the current reference signal Iref1, and ensures that the circuit achieves constant current output.

[0014] Preferably, the driving control circuit comprises a PFC control chip, an operational amplifier U3, an operational amplifier U4 and an RS trigger A1, the positive phase input terminal of the operational amplifier U3 and the negative phase input terminal of the operational amplifier U4 input the second feedback signal transmitted by the voltage regulating circuit, the negative phase input terminal of the operational amplifier U3 inputs the voltage reference signal Vref2, the output terminal of the operational amplifier U3 is connected to the S terminal of the RS trigger A1, the positive phase input terminal of the operational amplifier U4 inputs the voltage reference signal Vref3, the output terminal of the operational amplifier U4 is connected to the R terminal of the RS trigger A1, the Q terminal and the non-Q terminal of the RS trigger A1 are both connected to the PFC control chip, and the PFC control chip is connected to the switch tube S0. The PFC control chip controls the switch tube S0 according to the output result of the RS trigger, so that the output voltage of the PFC main circuit is stable at the voltage reference signal Vref1, and the constant voltage output of the circuit is realized.

[0015] The beneficial effects of the present invention are: (1) by different coupling coefficients between the two secondary windings of the transformer and the primary winding, multi-channel output of the LED driver is realized; (2) by voltage detection by the voltage regulation circuit and regulation of the drive control circuit, constant voltage output of the LED driver is realized; (3) by current detection by the current regulation circuit and regulation of the frequency control drive circuit, constant current output of the LED driver is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the LED driver of the first embodiment.

[0017] Figure 2 1 is a schematic diagram of a LED driver circuit according to the first embodiment.

[0018] Figure 3 It is a schematic diagram of a voltage regulation circuit of the first embodiment.

[0019] Figure 4 It is a schematic diagram of the current regulation circuit of the first embodiment.

[0020] In the figure, 1. power supply, 2. PFC main circuit, 3. resonant DC-DC circuit, 4. current regulation circuit, 5. voltage regulation circuit, 6. frequency control drive circuit, 7. isolation circuit, 8. drive control circuit. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0022] Embodiment 1: A LED driver, such as Figure 1As shown, it includes a PFC main circuit 2, a drive control circuit 8, an isolation circuit 7, a voltage regulation circuit 5, a frequency control drive circuit 6, a current regulation circuit 4 and a resonant DC-DC circuit 3. The input end of the PFC main circuit 2 serves as the input end of the LED driver and is used to connect to the power supply 1. The output end of the PFC main circuit 2 is connected to the input end of the resonant DC-DC circuit 3. The output end of the resonant DC-DC circuit 3 includes a constant voltage output end and a constant current output end. The input end of the current regulation circuit 4 is connected to the constant current output end of the resonant DC-DC circuit 3. The output end of the current regulation circuit 4 is connected to the frequency control drive circuit 6. The current regulation circuit 4 is used to detect the current output from the constant current output end and output a first feedback signal to the frequency control drive circuit 6. The frequency control driving circuit 6 outputs a first driving signal to the resonant DC-DC circuit 3 according to the size of the first feedback signal, and the working frequency of the resonant DC-DC circuit 3 is used to maintain the current outputted from the constant current output end constant. The input end of the voltage regulating circuit 5 is connected to the constant voltage output end of the resonant DC-DC circuit 3, and the output end of the voltage regulating circuit 5 is connected to the driving control circuit 8 via the isolation circuit. The voltage regulating circuit 5 is used to detect the voltage outputted from the constant voltage output end and output a second feedback signal to the driving control circuit 8 via the isolation circuit. The driving control circuit 8 outputs a second driving signal to the PFC main circuit 2 according to the size of the second feedback signal to make its output voltage constant, thereby making the voltage of the constant voltage output end constant.

[0023] like Figure 2 As shown, the PFC main circuit 2 includes an inductor L, a switch tube S0, a diode D1 and a capacitor C0. One end of the inductor L is connected to the positive electrode of the power supply 1, and the other end of the inductor L is respectively connected to one end of the switch tube S0 and the anode of the diode D1. The other end of the switch tube S0 is respectively connected to one end of the capacitor C0 and the negative electrode of the power supply 1. The other end of the capacitor C0 is connected to the cathode of the diode D1. Both ends of the capacitor C0 are also connected to the resonant DC-DC circuit 3 as the output ends of the PFC main circuit 2.

[0024] The resonant DC-DC circuit 3 includes a switch unit, a resonant capacitor Cr, a transformer, a diode D2, a diode D3, a diode D4, a diode D5, a capacitor C1, a capacitor C2 and a resistor Rs. The transformer includes a primary winding N1, a secondary winding M1 and a secondary winding M2. The primary winding N1 and the resonant capacitor Cr are connected in series and then connected to the switch unit. The other two ends of the switch unit serve as input ends of the resonant DC-DC circuit. The secondary winding M1 uses a first rectified output end after rectification as a constant voltage output end, and the secondary winding M2 uses a second rectified output end after rectification as a constant current output end. The coupling coefficient between the secondary winding M1 and the primary winding N1 is greater than the coupling coefficient between the secondary winding M2 and the primary winding N1. The switch unit includes a switch tube S1 and a switch tube S2. The first end of the switch tube S1 serves as the positive input end of the resonant DC-DC circuit. The second end of the switch tube S1 is respectively connected to the first end of the switch tube S2 and one end of the primary winding N1. The second end of the switch tube S2 serves as the negative input end of the resonant DC-DC circuit and is connected to one end of the resonant capacitor Cr. The other end of the resonant capacitor Cr is connected to the other end of the primary winding N1. The secondary winding M1 and the secondary winding M2 have tapped ends. The first end of the secondary winding M1 is connected to the anode of the diode D2. The second end of the secondary winding M1 is connected to the anode of the diode D2 via the diode D3. The cathode of the diode D2 and the tapped end of the secondary winding M1 are connected to the capacitor C1. The two ends of the capacitor C1 serve as constant voltage output ends. The first end of the secondary winding M2 is connected to the anode of the diode D4. The second end of the secondary winding M2 is connected to the anode of the diode D4 via the diode D5. The cathode of the diode D4 is connected to the first end of the capacitor C2. The tapped end of the secondary winding M2 is respectively connected to the second end of the capacitor C2 and the first end of the resistor Rs. The two ends of the capacitor C2 serve as constant current output ends. The second end of the resistor Rs is connected to the current regulating circuit 4.

[0025] The isolation circuit 7 includes a photocoupler, an input end of the photocoupler is connected to the voltage regulating circuit 5 , and an output end of the photocoupler is connected to the drive control circuit 8 .

[0026] The frequency control driving circuit 6 includes a resonance control chip, a voltage-controlled oscillator and a driving circuit. The voltage-controlled oscillator receives the first feedback signal transmitted by the current regulating circuit 4 and determines the magnitude of the frequency of the switch tube S1 and the switch tube S2 according to the magnitude of the first feedback signal, and transmits the frequency signal to the resonance control chip. The resonance control chip generates a driving signal according to the frequency signal through the driving circuit and outputs it to the switch tube S1 and the switch tube S2.

[0027] The drive control circuit 8 includes a PFC control chip, an operational amplifier U3, an operational amplifier U4 and an RS trigger A1. The positive phase input terminal of the operational amplifier U3 and the negative phase input terminal of the operational amplifier U4 input the second feedback signal transmitted by the voltage regulation circuit 5, the negative phase input terminal of the operational amplifier U3 inputs the voltage reference signal Vref2, the output terminal of the operational amplifier U3 is connected to the S terminal of the RS trigger A1, the positive phase input terminal of the operational amplifier U4 inputs the voltage reference signal Vref3, the output terminal of the operational amplifier U4 is connected to the R terminal of the RS trigger A1, the Q terminal and the Q non-terminal of the RS trigger A1 are both connected to the PFC control chip, and the PFC control chip is connected to the switch tube S0.

[0028] like Figure 3 As shown, the voltage regulating circuit 5 includes an operational amplifier U1, a resistor R1, a resistor R2, a resistor R3 and a capacitor C4. The negative phase input terminal of the operational amplifier U1 is respectively connected to the first end of the capacitor C4, one end of the resistor R1 and one end of the resistor R2, the other end of the resistor R1 is connected to the first end of the capacitor C1, the other end of the resistor R2 is connected to the second end of the capacitor C1, the second end of the capacitor C4 is connected to the output terminal of the operational amplifier U1 via the resistor R3, and the positive phase input terminal of the operational amplifier U1 inputs the voltage reference signal Vref1.

[0029] like Figure 4 As shown, the current regulating circuit 4 includes an operational amplifier U2, a capacitor C5 and a resistor R4. The negative phase input terminal of the operational amplifier U2 is respectively connected to the first end of the capacitor C5 and the second end of the resistor Rs, the second end of the capacitor C5 is connected to the output end of the operational amplifier U2 via the resistor R4, and the positive phase input terminal of the operational amplifier inputs the current reference signal Iref1.

[0030] In a specific application, 220V AC is rectified by a rectifier circuit and then enters the PFC main circuit 2 through a power supply 1. The input voltage amplitude of the PFC main circuit 2 is sinusoidally changed. The inductor L, the switch tube S0, and the diode D1 form a Boost circuit. Through the control of the drive control circuit, the input current of the Boost circuit is close to the input voltage, that is, close to a sine wave, thereby realizing the PFC function. The PFC main circuit 2 implemented by the Boost circuit outputs a DC voltage Vbus under the control of the voltage regulating circuit 5 and the drive control circuit 8, and inputs the DC voltage Vbus with a relatively stable amplitude into the resonant DC-DC circuit 3. The switch tube S1, the switch tube S2, the resonant capacitor Cr, the diode D2, the diode D3, the diode D4, the diode D5 and the transformer in the resonant DC-DC circuit 3 form an LLC half-bridge resonant circuit, and the voltage output by the PFC main circuit 2 is DC-DC converted. The coupling coefficients of the two secondary windings and the primary winding of the transformer are different. The secondary winding M1 is tightly coupled with the primary winding N1, so that the voltage output by the first path is highly correlated with the primary winding N1 of the transformer of the resonant DC-DC circuit 3. The switch tube S0 of the PFC main circuit 2 is controlled by the voltage regulating circuit 5 and the drive control circuit 8. Control, by controlling the switch tube S0 to adjust the value of the output voltage Vbus of the PFC main circuit 2, so that the value of the output voltage Vbus of the PFC main circuit 2 is stabilized at the value set by the voltage reference signal Vref1, so that the first output voltage of the resonant DC-DC circuit 3 is stabilized at a certain value, and the constant voltage output of the LED driver is realized. The coupling degree between the secondary winding M2 and the primary winding N1 is low, and there is a large leakage inductance. The switch tubes S1 and S2 of the resonant DC-DC circuit 3 are controlled by the current regulation circuit 4 and the frequency control drive circuit 6, so that the second output current is stabilized at the current reference signal Iref1, and the second output current of the resonant DC-DC circuit 3 is stabilized at a certain value, and the constant current output of the LED driver is realized. Furthermore, when the same LED driver has multiple outputs, both constant voltage output and constant current output are realized.

[0031] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. An LED driver, characterized in that: include: A PFC main circuit, a drive control circuit, an isolation circuit, a voltage regulation circuit, a frequency control drive circuit, a current regulation circuit and a resonant DC-DC circuit. The input end of the PFC main circuit serves as the input end of the LED driver and is used to connect to a power supply. The output end of the PFC main circuit is connected to the input end of the resonant DC-DC circuit. The output end of the resonant DC-DC circuit includes a constant voltage output end and a constant current output end. The input end of the current regulation circuit is connected to the constant current output end. The output end of the current regulation circuit is connected to the frequency control drive circuit. The current regulation circuit is used to detect the current output by the constant current output end and output a first feedback signal to the frequency control drive circuit. The frequency control drive circuit outputs a first drive signal to the resonant DC-DC circuit according to the size of the first feedback signal. The current output by the constant current output end is maintained constant by the operating frequency of the resonant DC-DC circuit. The input end of the circuit is connected to the constant voltage output end, the output end of the voltage regulating circuit is connected to the drive control circuit via the isolation circuit, the voltage regulating circuit is used to detect the voltage output by the constant voltage output end and output a second feedback signal to the drive control circuit through the isolation circuit, the drive control circuit outputs a second drive signal to the PFC main circuit according to the size of the second feedback signal to make its output voltage constant, thereby making the voltage of the constant voltage output end constant; the isolation circuit includes a photoelectric coupler, the input end of the photoelectric coupler is connected to the voltage regulating circuit, and the output end of the photoelectric coupler is connected to the drive control circuit; the resonant DC-DC circuit also includes a resonant capacitor Cr, a transformer and a switch unit, the transformer includes a primary winding N1, a secondary winding M1 and a secondary winding M2, the primary winding N1 and the resonant capacitor Cr are connected in series and then connected to the switch unit, and the other two ends of the switch unit serve as the input end of the resonant DC-DC circuit.

2. The LED driver according to claim 1, characterized in that: The PFC main circuit includes an inductor L, a switch tube S0, a diode D1 and a capacitor C0. One end of the inductor L is connected to the positive electrode of the power supply, the other end of the inductor L is respectively connected to one end of the switch tube S0 and the anode of the diode D1, the other end of the switch tube S0 is respectively connected to one end of the capacitor C0 and the negative electrode of the power supply, the other end of the capacitor C0 is connected to the cathode of the diode D1, and the two ends of the capacitor C0 are also connected to the resonant DC-DC circuit as the output ends of the PFC main circuit.

3. The LED driver according to claim 1, characterized in that: The secondary winding M1 uses a first rectified output end as a constant voltage output end after rectification, and the secondary winding M2 uses a second rectified output end as a constant current output end after rectification.

4. The LED driver according to claim 3, characterized in that: The coupling coefficient between the secondary winding M1 and the primary winding N1 is greater than the coupling coefficient between the secondary winding M2 and the primary winding N1.

5. The LED driver according to claim 3, characterized in that: The switch unit in the resonant DC-DC circuit includes a switch tube S1 and a switch tube S2; the resonant DC-DC circuit also includes a diode D2, a diode D3, a diode D4, a diode D5, a capacitor C1, a capacitor C2 and a resistor Rs, the first end of the switch tube S1 serves as the input positive end of the resonant DC-DC circuit, the second end of the switch tube S1 is respectively connected to the first end of the switch tube S2 and one end of the primary winding N1, the second end of the switch tube S2 serves as the input negative end of the resonant DC-DC circuit and is connected to one end of the resonant capacitor Cr, the other end of the resonant capacitor Cr is connected to the other end of the primary winding N1, the secondary winding M1 and the secondary winding M2 have tap ends, the first end of the secondary winding M1 is connected to the The anode of the diode D2 is connected, the second end of the secondary winding M1 is connected to the anode of the diode D2 via the diode D3, the cathode of the diode D2 and the tap end of the secondary winding M1 are connected to the capacitor C1, and the two ends of the capacitor C1 serve as the constant voltage output ends; the first end of the secondary winding M2 is connected to the anode of the diode D4, the second end of the secondary winding M2 is connected to the anode of the diode D4 via the diode D5, the cathode of the diode D4 is connected to the first end of the capacitor C2, the tap end of the secondary winding M2 is respectively connected to the second end of the capacitor C2 and the first end of the resistor Rs, the two ends of the capacitor C2 serve as the constant current output ends, and the second end of the resistor Rs is connected to the current regulating circuit.

6. The LED driver according to claim 5, characterized in that: The voltage regulating circuit includes an operational amplifier U1, a resistor R1, a resistor R2, a resistor R3 and a capacitor C4. The negative phase input terminal of the operational amplifier U1 is respectively connected to the first end of the capacitor C4, one end of the resistor R1 and one end of the resistor R2. The other end of the resistor R1 is connected to the first end of the capacitor C1. The other end of the resistor R2 is connected to the second end of the capacitor C1. The second end of the capacitor C4 is connected to the output terminal of the operational amplifier U1 via the resistor R3. The positive phase input terminal of the operational amplifier U1 inputs the voltage reference signal Vref1.

7. The LED driver according to claim 5, characterized in that: The current regulating circuit includes an operational amplifier U2, a capacitor C5 and a resistor R4. The negative phase input terminal of the operational amplifier U2 is respectively connected to the first end of the capacitor C5 and the second end of the resistor Rs. The second end of the capacitor C5 is connected to the output end of the operational amplifier U2 via the resistor R4. The positive phase input terminal of the operational amplifier inputs a current reference signal Iref1.

8. The LED driver according to claim 5, characterized in that: The frequency control driving circuit includes a resonance control chip, a voltage-controlled oscillator and a driving circuit. The voltage-controlled oscillator receives a first feedback signal transmitted by a current regulation circuit and determines the magnitude of the frequency of the switch tube S1 and the switch tube S2 according to the magnitude of the first feedback signal, and transmits the frequency signal to the resonance control chip. The resonance control chip generates a driving signal through a driving circuit according to the frequency signal and outputs it to the switch tube S1 and the switch tube S2.

9. The LED driver according to claim 2, characterized in that: The drive control circuit includes a PFC control chip, an operational amplifier U3, an operational amplifier U4 and an RS trigger A1. The positive phase input terminal of the operational amplifier U3 and the negative phase input terminal of the operational amplifier U4 input the second feedback signal transmitted by the voltage regulation circuit, the negative phase input terminal of the operational amplifier U3 inputs the voltage reference signal Vref2, the output terminal of the operational amplifier U3 is connected to the S terminal of the RS trigger A1, the positive phase input terminal of the operational amplifier U4 inputs the voltage reference signal Vref3, the output terminal of the operational amplifier U4 is connected to the R terminal of the RS trigger A1, the Q terminal and the Q non-terminal of the RS trigger A1 are both connected to the PFC control chip, and the PFC control chip is connected to the switch tube S0.

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