Low-voltage power supply adapter circuit

Abstract

The invention discloses a low-voltage power supply adaptation circuit, and relates to the technical field of power supply adaptation. According to the main technical scheme, an input module is connected with an input power supply; the input end of the active PFC module is connected with the output end of the input module; the input end of the LCC resonance module is connected with the output end of the input module, and the LCC resonance module is connected with the active PFC module; the input end of the output module is connected with the output end of the active PFC module; the input end of the feedback module is connected with the output end of the output module, and the output end of the feedback module is connected with the control module. Through the soft switching technology of the LCC resonance module, switching loss and heat dissipation are effectively reduced. Meanwhile, in combination with power factor correction of the active PFC module, the overall energy efficiency is effectively improved, and the energy utilization rate of the power adapter is further improved. The feedback module provides quick response and isolation feedback, and in combination with the synchronous rectification of the output module, the fluctuation of the output voltage is effectively reduced, so that the load regulation rate and the stability of linear regulation are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power adapter, in particular to a low-voltage power adapter circuit. BACKGROUND

[0002] Power adapter, also known as AC-DC power adapter, is a device that converts input AC power into output DC power.

[0003] Most of the existing power adapters use hard switching topology (such as flyback converter), which causes high energy loss and heat dissipation in the switching process of the power adapter, thereby greatly reducing the energy efficiency of the power adapter. SUMMARY

[0004] The purpose of the present application is to provide a low-voltage power adapter circuit, which solves the problem that most of the existing power adapters use hard switching topology, which causes high energy loss and heat dissipation in the switching process of the power adapter, thereby greatly reducing the energy efficiency of the power adapter.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] A low-voltage power adapter circuit is provided, comprising an input module, an active PFC module, an LCC resonant module, an output module and a feedback module. The input module is used to connect the input power. The input end of the active PFC module is connected with the output end of the input module. The input end of the LCC resonant module is connected with the output end of the input module, and the LCC resonant module is connected with the active PFC module. The input end of the output module is connected with the output end of the active PFC module. The input end of the feedback module is connected with the output end of the output module, and the output end of the feedback module is connected with the active PFC module.

[0007] A further scheme is: the input module includes fuse F1, capacitor CX2, voltage-dependent resistor MOV1, common-mode inductor LF3, capacitor CY2, capacitor CY3, capacitor CX1, common-mode inductor LF1, rectifier BD1, magnetic ring magnetic core L1, capacitor C2, PFC inductor L2, diode D1, thermistor RT1, resistor R5, resistor R6, capacitor C4; one end of the fuse F1 is used for connecting the L pole of the input power supply; the other end of the fuse F1 is connected with one end of the capacitor CX2, one end of the voltage-dependent resistor MOV1, and the 2nd pin of the common-mode inductor LF3; the other end of the capacitor CX2, the other end of the voltage-dependent resistor MOV1, and the 3rd pin of the common-mode inductor LF3 are all used for connecting the N pole of the input power supply; the 1st pin of the common-mode inductor LF3 is connected with one end of the capacitor CY2, one end of the capacitor CX1, and the 2nd pin of the common-mode inductor LF1; the 4th pin of the common-mode inductor LF3 is connected with one end of the capacitor CY3, the other end of the capacitor CX1, and the 3rd pin of the common-mode inductor LF1; the other end of the capacitor CY2 and the other end of the capacitor CY3 are both grounded; the 1st pin of the common-mode inductor LF1 is connected with the 2nd pin of the rectifier BD1; the 4th pin of the common-mode inductor LF1 is connected with the 3rd pin of the rectifier BD1; the 1st pin of the rectifier BD1 is connected with one end of the magnetic ring magnetic core L1, the anode of the diode D1, and one end of the capacitor C1; the other end of the capacitor C1 is connected with one end of the capacitor C2; the other end of the magnetic ring magnetic core L1 and the other end of the capacitor C2 are both connected with the 1st pin of the PFC inductor L2; the 3rd pin of the PFC inductor L2 is connected with one end of the capacitor C4 and the input end of the LCC resonant module; the cathode of the diode D1 is connected with one end of the thermistor RT1; the other end of the thermistor RT1 is connected with one end of the resistor R5, one end of the resistor R6, and the input end of the active PFC module; the other end of the resistor R5 and one end of the resistor R6 are both connected with the other end of the capacitor C4.

[0008] Further scheme is: the active PFC module contains input part, transformation part and control part; the input part contains electrolytic capacitor C3, capacitor C44, MOS tube Q4, capacitor C9, diode D3, resistance R48, resistance R8, resistance R9, resonant inductor L3, MOS tube Q5, capacitor C12, resistance R32, resistance R49, resistance R31, capacitor C13; the drain electrode of MOS tube Q4 is connected with one end of capacitor C9, one end of capacitor C44, the positive pole of electrolytic capacitor C3, the other end of thermistor RT1, the output end of the LCC resonant module; the negative pole of electrolytic capacitor C3, the other end of capacitor C44 are grounded; the source electrode of MOS tube Q4 is connected with the other end of capacitor C9, one end of resistance R48, one end of resonant inductor L3, one end of capacitor C12, the drain electrode of MOS tube Q5, control part; the other end of resonant inductor L3 is connected with the input end of transformation part; the output end of transformation part is connected with the input end of the output module; the gate electrode of MOS tube Q4 is connected with the other end of resistance R48, the positive pole of diode D3, one end of resistance R8; the other end of resistance R8, the negative pole of diode D3 are connected with one end of resistance R9; the other end of resistance R9 is connected with control part; the source electrode of MOS tube Q5, the other end of capacitor C12, one end of capacitor C13, one end of resistance R49 are grounded; the other end of capacitor C13 is connected with the input end of transformation part, control part; the gate electrode of MOS tube Q5 is connected with the other end of resistance R49, one end of resistance R32, the positive pole of diode D4; the negative pole of diode D4, the other end of resistance R32 are connected with one end of resistance R31; the other end of resistance R31 is connected with control part.

[0009] A further solution is that the voltage conversion part comprises a transformer T1, a diode D5, a diode D6, a resistor R47, an electrolytic capacitor C51, a voltage stabilizing diode D13, a resistor R50, a transistor Q10, a resistor R10, a resistor R45, a capacitor C30 and an electrolytic capacitor C29; the transformer T1 comprises a first voltage conversion unit T1A and a second voltage conversion unit T1B; the 2nd pin of the first voltage conversion unit T1A is connected with the other end of the resonant inductor L3; the 1st pin of the first voltage conversion unit T1A is connected with the other end of the capacitor C13; the 8th pin of the first voltage conversion unit T1A, the 9th pin of the first voltage conversion unit T1A, the 10th pin of the first voltage conversion unit T1A and the 12th pin of the first voltage conversion unit T1A are all connected with the input end of the output module; the 3rd pin of the second voltage conversion unit T1B is grounded; the 5th pin of the second voltage conversion unit T1B is connected with the anode of the diode D5; the 6th pin of the second voltage conversion unit T1B is connected with the anode of the diode D6; the cathode of the diode D5 and the cathode of the diode D6 are both connected with one end of the resistor R47; the other end of the resistor R47 is connected with the anode of the electrolytic capacitor C51, one end of the resistor R50, the collector of the transistor Q10 and one end of the resistor R10; the cathode of the electrolytic capacitor C51 and the anode of the voltage stabilizing diode D13 are both grounded; the cathode of the voltage stabilizing diode D13 and the other end of the resistor R50 are both connected with the base of the transistor Q10; the emitter of the transistor Q10 is connected with the other end of the resistor R10, one end of the resistor R45 and the anode of the electrolytic capacitor C29; the other end of the resistor R45 is connected with one end of the capacitor C30; the other end of the capacitor C30 and the cathode of the electrolytic capacitor C29 are both grounded.

[0010] Further scheme is: the control part contains combination control chip U1, diode D10, capacitor C25, resistance R33, resistance R34, capacitor C11, capacitor C10, capacitor C26, resistance R46, capacitor C24, capacitor C28, resistance R44, capacitor C27; the 5th pin of combination control chip U1 is connected with the input end of the LCC resonance module; the 6th pin of combination control chip U1 is connected with the other end of resistance R31; the 8th pin of combination control chip U1 is connected with the input end of the LCC resonance module; the 9th pin of combination control chip U1 is connected with the other end of resistance R9; the 10th pin of combination control chip U1 is connected with one end of capacitor C25 and the negative electrode of diode D10; the positive electrode of diode D10 is connected with the other end of resistance R31; the 11th pin of combination control chip U1 is connected with the other end of capacitor C25 and the source electrode of MOS tube Q4; the 14th pin of combination control chip U1 is connected with one end of resistance R44, one end of resistance R34, one end of capacitor C11, one end of capacitor C28 and one end of capacitor C24; the other end of resistance R44, the other end of capacitor C28 and the other end of capacitor C24 are grounded; the other end of resistance R34 is connected with one end of resistance R33; the other end of resistance R33, the other end of capacitor C11 and one end of capacitor C10 are connected with the other end of capacitor C13; the 15th pin of combination control chip U1 is connected with one end of capacitor C27; the other end of capacitor C27 is connected with one end of resistance R46, the other end of capacitor C10 and one end of capacitor C26; the other end of capacitor C26 and the other end of resistance R46 are grounded; the 16th pin of combination control chip U1 is connected with the output end of the feedback module.

[0011] Further scheme is: the LCC resonance module contains diode D2, MOS tube Q1, MOS tube Q2, triode Q1, resistance R2, resistance R3, resistance R4, resistance R15, resistance R16, triode Q7, resistance R35, capacitor C41, resistance R37, resistance R17, resistance R20, resistance R18, capacitor C6, resistance R14, resistance R1; the negative electrode of diode D2 is connected with the other end of thermistor RT1; the drain of MOS tube is connected with the positive electrode of diode D2; the gate of MOS tube is connected with the one end of resistance R2 and the emitter of triode Q1; the source of MOS tube, the one end of resistance R4, the one end of resistance R17, the one end of resistance R35, the one end of resistance R37, the one end of resistance R20, the one end of capacitor C6 and the source of MOS tube Q3 are all grounded; the collector of triode Q1 is connected with the other end of resistance R4; the base of triode Q1 is connected with the one end of resistance R3; the other end of resistance R3, the other end of resistance R2, the one end of resistance R15, the one end of resistance R16 are all connected with the one end of resistance R14; the other end of resistance R14 is connected with the 5th pin of combination control chip U1; the other end of resistance R15 is connected with the emitter of triode Q7, the gate of MOS tube Q3 and the other end of resistance R35; the drain of MOS tube Q3, the one end of capacitor C41 and the one end of resistance R1 are all connected with the 3rd pin of PFC inductor L2; the other end of capacitor C41 is connected with the other end of resistance R37; the other end of resistance R1 is connected with the 8th pin of combination control chip U1; the other end of resistance R16 is connected with the base of triode Q7; the collector of triode Q7 is connected with the other end of resistance R17; the other end of resistance R20 is connected with the one end of resistance R18; the other end of resistance R18 is connected with the other end of capacitor C6.

[0012] A further solution is that the output module comprises an output unit and an IC control unit; the output unit comprises a capacitor CY5, a capacitor CY1, a capacitor C5, a resistor R11, a MOS tube Q6, a resistor R30, a capacitor C16, a resistor R12, a MOS tube Q8, a resistor R36, an electrolytic capacitor C15, an electrolytic capacitor C17, an electrolytic capacitor C18, a capacitor CY4, a resistor R27, a resistor R28, a resistor R19, a capacitor C31, and a common-mode inductor LF4; one end of the capacitor CY5 is connected with the positive pole of the electrolytic capacitor C15, the positive pole of the electrolytic capacitor C17, the positive pole of the electrolytic capacitor C18, one end of the capacitor C31, the No. 1 pin of the common-mode inductor LF4, the No. 8 pin of the first transformer unit T1A, and the No. 9 pin of the first transformer unit T1A; the other end of the capacitor CY5 is connected with one end of the capacitor CY1, and the other end of the capacitor CY1 is grounded; the No. 10 pin of the first transformer unit T1A is connected with one end of the capacitor C5, and the other end of the capacitor C5 is connected with one end of the resistor R11; the other end of the resistor R11 is connected with the source electrode of the MOS tube Q6, one end of the resistor R30, one end of the resistor R12, the IC control unit, one end of the resistor R36, the source electrode of the MOS tube Q8, the negative pole of the electrolytic capacitor C17, the negative pole of the electrolytic capacitor C18, one end of the resistor R19, one end of the capacitor CY4, one end of the resistor R27, and the other end of the capacitor C31, and the other end of the resistor R11 is grounded; the other end of the resistor R12 is connected with one end of the capacitor C16, and the other end of the capacitor C16 is connected with the drain electrode of the MOS tube Q8 and the IC control unit, and the No. 12 pin of the first transformer unit T1A; the drain electrode of the MOS tube Q6, the gate electrode of the MOS tube Q6, the other end of the resistor R30, the gate electrode of the MOS tube, the other end of the resistor R36, and the negative pole of the electrolytic capacitor C15 are connected with the IC control unit; the other end of the resistor R27 is connected with one end of the resistor R28, and the other end of the resistor R28 and the other end of the capacitor CY4 are grounded; the other end of the resistor R19 is connected with the input end of the feedback module and the No. 4 pin of the common-mode inductor LF4; the No. 2 pin of the common-mode inductor LF4 is used for outputting a positive voltage, and the No. 3 pin of the common-mode inductor LF4 is used for outputting a negative voltage.

[0013] Further scheme is: the IC control unit contains resistance R13, resistance R38, IC control chip U2, resistance R85, resistance R88, resistance R87, capacitor C22, resistance R82, resistance R83, resistance R84, capacitor C20, IC control chip U2 is TEA1995T;IC control chip U2's 5th foot and resistance R88's one end, resistance R87's one end are connected;Resistance R87's other end is grounded;Resistance R88's other end is connected with resistance R11's other end;IC control chip U2's 6th foot is connected with resistance R85's one end;Resistance R85's other end is connected with MOS tube Q6's drain electrode;IC control chip U2's 7th foot is connected with capacitor C20's one end;IC control chip U2's 8th foot is connected with resistance R13's one end;Resistance R13's other end and resistance R30's other end, MOS tube Q6's grid are connected;IC control chip U2's 2nd foot and capacitor C20's other end, resistance R83's one end, electrolytic capacitor C15's negative pole are connected;IC control chip U2's 3rd foot and capacitor C22's one end, resistance R82's one end are connected;Capacitor C22's other end, resistance R82's other end, resistance R84's one end are connected with capacitor C16's other end;IC control chip U2's 4th foot and resistance R83's other end, resistance R84's other end are connected;IC control chip U2's 1st foot is connected with resistance R38's one end;Resistance R38's other end and resistance R36's other end, MOS tube Q8's grid are connected.

[0014] Further scheme is that the feedback module contains photoelectric coupler IC1, capacitor C39, resistor R58, resistor R80, diode ZD1, resistor R52, resistor R51, capacitor C32, capacitor C33, resistor R62, voltage reference chip U6, resistor R66, resistor R65, voltage reference chip U6 is ME431AXG, photoelectric coupler IC1 contains photoelectric coupling input unit IC1B and photoelectric coupling output unit IC1A, the No.1 pin of photoelectric coupling input unit IC1B is connected with the one end of resistor R51 and the one end of resistor R80, the one end of resistor R80 is connected with the anode of diode ZD1, the cathode of diode ZD1 is connected with the one end of resistor R52, the other end of resistor R52 is connected with the one end of capacitor C32, the one end of capacitor C33, the one end of resistor R65, the one end of resistor R66 and the reference of voltage reference chip U6, the anode of voltage reference chip U6, the other end of resistor R65 and the other end of resistor R66 are grounded, the other end of capacitor C33 is connected with the one end of resistor R62, the other end of resistor R62, the other end of capacitor C32, the other end of resistor R51 and the No.2 pin of photoelectric coupling input unit IC1B are connected with the other end of resistor R19, the No.4 pin of photoelectric coupling output unit IC1A and the one end of capacitor C39 are connected with the No.16 pin of combination control chip U1, the No.3 pin of photoelectric coupling output unit IC1A is connected with the one end of resistor R58, the other end of resistor R58 and the other end of capacitor C39 are grounded.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] On the one hand, the soft switching technology of the LCC resonant module effectively reduces the switching loss and heat dissipation. At the same time, combined with the power factor correction of the active PFC module, the overall energy efficiency is effectively improved, thereby improving the energy utilization rate of the power adapter. On the other hand, the feedback module provides fast response and isolated feedback, combined with the synchronous rectification of the output module, effectively reduces the fluctuation of the output voltage, thereby ensuring the stability of the load regulation rate and linear regulation. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is an electrical block diagram schematic of a low-voltage power supply adapter circuit in the present embodiment;

[0018] Figure 2 It is a circuit structure topology diagram of an input module of a low-voltage power supply adapter circuit in the present embodiment;

[0019] Figure 3 It is a circuit structure topology diagram of the input part and the transformation part of an active PFC module of a low-voltage power supply adapter circuit in the present embodiment;

[0020] Figure 4This is a circuit structure topology diagram of the control part of an active PFC module for a low-voltage power adapter circuit in this embodiment;

[0021] Figure 5 This is a circuit structure topology diagram of an LCC resonant module for a low-voltage power adapter circuit in this embodiment;

[0022] Figure 6 This is a circuit structure topology diagram of an output module for a low-voltage power adapter circuit in this embodiment;

[0023] Figure 7 This is a circuit structure topology diagram of a feedback module for a low-voltage power adapter circuit in this embodiment. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Embodiment 1: This embodiment provides a low voltage power adapter circuit, such as Figures 1-7 As shown, it includes an input module, an active PFC module, an LCC resonant module, an output module and a feedback module, wherein the input module is used to connect to an input power supply; the input end of the active PFC module is connected to the output end of the input module; the input end of the LCC resonant module is connected to the output end of the input module, and the LCC resonant module is connected to the active PFC module; the input end of the output module is connected to the output end of the active PFC module; the input end of the feedback module is connected to the output end of the output module, and the output end of the feedback module is connected to the active PFC module.

[0026] In this embodiment, if Figure 2As shown, the input module includes fuse F1, capacitor CX2, voltage-dependent resistor MOV1, common-mode inductor LF3, capacitor CY2, capacitor CY3, capacitor CX1, common-mode inductor LF1, rectifier BD1, magnetic ring magnetic core L1, capacitor C2, PFC inductor L2, diode D1, thermistor RT1, resistor R5, resistor R6, and capacitor C4. One end of fuse F1 is connected to the L terminal of an input power supply. The other end of fuse F1 is connected to one end of capacitor CX2, one end of voltage-dependent resistor MOV1, and the 2nd pin of common-mode inductor LF3. The other end of capacitor CX2, the other end of voltage-dependent resistor MOV1, and the 3rd pin of common-mode inductor LF3 are connected to the N terminal of the input power supply. The 1st pin of common-mode inductor LF3 is connected to one end of capacitor CY2, one end of capacitor CX1, and the 2nd pin of common-mode inductor LF1. The 4th pin of common-mode inductor LF3 is connected to one end of capacitor CY3, the other end of capacitor CX1, and the 3rd pin of common-mode inductor LF1. The other end of capacitor CY2 and the other end of capacitor CY3 are connected to ground. The 1st pin of common-mode inductor LF1 is connected to the 2nd pin of rectifier BD1. The 4th pin of common-mode inductor LF1 is connected to the 3rd pin of rectifier BD1. The 1st pin of rectifier BD1 is connected to one end of magnetic ring magnetic core L1, the anode of diode D1, and one end of capacitor C1. The other end of capacitor C1 is connected to one end of capacitor C2. The other end of magnetic ring magnetic core L1 and the other end of capacitor C2 are connected to the 1st pin of PFC inductor L2. The 3rd pin of PFC inductor L2 is connected to one end of capacitor C4 and the input terminal of the LCC resonant module. The cathode of diode D1 is connected to one end of thermistor RT1. The other end of thermistor RT1 is connected to one end of resistor R5, one end of resistor R6, and the input terminal of the active PFC module. The other end of resistor R5 and one end of resistor R6 are connected to the other end of capacitor C4.

[0027] In this embodiment, the active PFC module includes an input portion, a transformation portion, and a control portion. As shown in FIG. 2, the input portion includes a voltage-dependent resistor MOV1, a common-mode inductor LF3, a capacitor CX2, a capacitor CY2, a capacitor CY3, a capacitor CX1, a common-mode inductor LF1, a rectifier BD1, a magnetic ring magnetic core L1, a capacitor C2, a PFC inductor L2, a diode D1, a thermistor RT1, a resistor R5, a resistor R6, and a capacitor C4. Figure 3As shown, the input part includes electrolytic capacitor C3, capacitor C44, MOS tube Q4, capacitor C9, diode D3, resistor R48, resistor R8, resistor R9, resonant inductor L3, MOS tube Q5, capacitor C12, resistor R32, resistor R49, resistor R31, capacitor C13; the drain of MOS tube Q4 is connected with one end of capacitor C9, one end of capacitor C44, the positive pole of electrolytic capacitor C3, the other end of thermistor RT1, the output end of the LCC resonant module; the negative pole of electrolytic capacitor C3, the other end of capacitor C44 are grounded; the source of MOS tube Q4 is connected with the other end of capacitor C9, one end of resistor R48, one end of resonant inductor L3, one end of capacitor C12, the drain of MOS tube Q5, the control part; the other end of resonant inductor L3 is connected with the input end of the voltage transformation part; the output end of the voltage transformation part is connected with the input end of the output module; the gate of MOS tube Q4 is connected with the other end of resistor R48, the positive pole of diode D3, one end of resistor R8; the other end of resistor R8, the negative pole of diode D3 are connected with one end of resistor R9; the other end of resistor R9 is connected with the control part; the source of MOS tube Q5, the other end of capacitor C12, one end of capacitor C13, one end of resistor R49 are grounded; the other end of capacitor C13 is connected with the input end of the voltage transformation part, the control part; the gate of MOS tube Q5 is connected with the other end of resistor R49, one end of resistor R32, the positive pole of diode D4; the negative pole of diode D4, the other end of resistor R32 are connected with one end of resistor R31; the other end of resistor R31 is connected with the control part.

[0028] In the embodiment, as Figure 3As shown, the voltage conversion part comprises a transformer T1, a diode D5, a diode D6, a resistor R47, an electrolytic capacitor C51, a voltage stabilizing diode D13, a resistor R50, a triode Q10, a resistor R10, a resistor R45, a capacitor C30 and an electrolytic capacitor C29; the transformer T1 comprises a first voltage conversion unit T1A and a second voltage conversion unit T1B; the 2nd pin of the first voltage conversion unit T1A is connected with the other end of the resonant inductor L3; the 1st pin of the first voltage conversion unit T1A is connected with the other end of the capacitor C13; the 8th pin of the first voltage conversion unit T1A, the 9th pin of the first voltage conversion unit T1A, the 10th pin of the first voltage conversion unit T1A and the 12th pin of the first voltage conversion unit T1A are all connected with the input end of the output module; the 3rd pin of the second voltage conversion unit T1B is grounded; the 5th pin of the second voltage conversion unit T1B is connected with the anode of the diode D5; the 6th pin of the second voltage conversion unit T1B is connected with the anode of the diode D6; the cathode of the diode D5 and the cathode of the diode D6 are both connected with one end of the resistor R47; the other end of the resistor R47 is connected with the anode of the electrolytic capacitor C51, one end of the resistor R50, the collector of the triode Q10 and one end of the resistor R10; the cathode of the electrolytic capacitor C51 and the anode of the voltage stabilizing diode D13 are both grounded; the cathode of the voltage stabilizing diode D13 and the other end of the resistor R50 are both connected with the base of the triode Q10; the emitter of the triode Q10 is connected with the other end of the resistor R10, one end of the resistor R45 and the anode of the electrolytic capacitor C29; the other end of the resistor R45 is connected with one end of the capacitor C30; the other end of the capacitor C30 and the cathode of the electrolytic capacitor C29 are both grounded.

[0029] In the present embodiment, as Figure 4As shown, the control part comprises a combination control chip U1, a diode D10, a capacitor C25, a resistor R33, a resistor R34, a capacitor C11, a capacitor C10, a capacitor C26, a resistor R46, a capacitor C24, a capacitor C28, a resistor R44, a capacitor C27; the No.5 pin of the combination control chip U1 is connected with the input end of the LCC resonant module; the No.6 pin of the combination control chip U1 is connected with the other end of the resistor R31; the No.8 pin of the combination control chip U1 is connected with the input end of the LCC resonant module; the No.9 pin of the combination control chip U1 is connected with the other end of the resistor R9; the No.10 pin of the combination control chip U1 is connected with one end of the capacitor C25 and the negative electrode of the diode D10; the positive electrode of the diode D10 is connected with the other end of the resistor R31; the No.11 pin of the combination control chip U1 is connected with the other end of the capacitor C25 and the source electrode of the MOS tube Q4; the No.14 pin of the combination control chip U1 is connected with one end of the resistor R44, one end of the resistor R34, one end of the capacitor C11, one end of the capacitor C28 and one end of the capacitor C24; the other end of the resistor R44, the other end of the capacitor C28 and the other end of the capacitor C24 are grounded; the other end of the resistor R34 is connected with one end of the resistor R33; the other end of the resistor R33, the other end of the capacitor C11 and one end of the capacitor C10 are connected with the other end of the capacitor C13; the No.15 pin of the combination control chip U1 is connected with one end of the capacitor C27; the other end of the capacitor C27 is connected with one end of the resistor R46, the other end of the capacitor C10 and one end of the capacitor C26; the other end of the capacitor C26 and the other end of the resistor R46 are grounded; the No.16 pin of the combination control chip U1 is connected with the output end of the feedback module.

[0030] In the embodiment, as Figure 5As shown, the LCC resonance module includes a diode D2, a MOS transistor Q1, a MOS transistor Q2, a transistor Q1, a resistor R2, a resistor R3, a resistor R4, a resistor R15, a resistor R16, a transistor Q7, a resistor R35, a capacitor C41, a resistor R37, a resistor R17, a resistor R20, a resistor R18, a capacitor C6, a resistor R14, and a resistor R1; the cathode of the diode D2 is connected to the other end of the thermistor RT1; the drain of the MOS transistor is connected to the anode of the diode D2; the gate of the MOS transistor is connected to one end of the resistor R2 and the emitter of the transistor Q1; the source of the MOS transistor, one end of the resistor R4, one end of the resistor R17, one end of the resistor R35, one end of the resistor R37, one end of the resistor R20, one end of the capacitor C6, and the source of the MOS transistor Q3 are all grounded; the collector of the transistor Q1 is connected to the other end of the resistor R4; the base of the transistor Q1 is connected to One end of resistor R3 is connected; the other end of resistor R3, the other end of resistor R2, one end of resistor R15, and one end of resistor R16 are all connected to one end of resistor R14; the other end of resistor R14 is connected to pin 5 of the combination control chip U1; the other end of resistor R15 is connected to the emitter of transistor Q7, the gate of MOS transistor Q3, and the other end of resistor R35; the drain of MOS transistor Q3, one end of capacitor C41, and one end of resistor R1 are all connected to pin 3 of PFC inductor L2; the other end of capacitor C41 is connected to the other end of resistor R37; the other end of resistor R1 is connected to pin 8 of the combination control chip U1; the other end of resistor R16 is connected to the base of transistor Q7; the collector of transistor Q7 is connected to the other end of resistor R17; the other end of resistor R20 is connected to one end of resistor R18; and the other end of resistor R18 is connected to the other end of capacitor C6.

[0031] In this embodiment, if Figure 6As shown, the output module comprises an output unit and an IC control unit; the output unit comprises a capacitor CY5, a capacitor CY1, a capacitor C5, a resistor R11, a MOS tube Q6, a resistor R30, a capacitor C16, a resistor R12, a MOS tube Q8, a resistor R36, an electrolytic capacitor C15, an electrolytic capacitor C17, an electrolytic capacitor C18, a capacitor CY4, a resistor R27, a resistor R28, a resistor R19, a capacitor C31, and a common-mode inductor LF4; one end of the capacitor CY5 is connected with the positive pole of the electrolytic capacitor C15, the positive pole of the electrolytic capacitor C17, the positive pole of the electrolytic capacitor C18, one end of the capacitor C31, the No. 1 pin of the common-mode inductor LF4, the No. 8 pin of the first transformer unit T1A, and the No. 9 pin of the first transformer unit T1A; the other end of the capacitor CY5 is connected with one end of the capacitor CY1, and the other end of the capacitor CY1 is grounded; the No. 10 pin of the first transformer unit T1A is connected with one end of the capacitor C5, and the other end of the capacitor C5 is connected with one end of the resistor R11; the other end of the resistor R11 is connected with the source electrode of the MOS tube Q6, one end of the resistor R30, one end of the resistor R12, the IC control unit, one end of the resistor R36, the source electrode of the MOS tube Q8, the negative pole of the electrolytic capacitor C17, the negative pole of the electrolytic capacitor C18, one end of the resistor R19, one end of the capacitor CY4, one end of the resistor R27, and the other end of the capacitor C31, and the other end of the resistor R11 is grounded; the other end of the resistor R12 is connected with one end of the capacitor C16, and the other end of the capacitor C16 is connected with the drain electrode of the MOS tube Q8 and the IC control unit, and the No. 12 pin of the first transformer unit T1A; the drain electrode of the MOS tube Q6, the gate electrode of the MOS tube Q6, the other end of the resistor R30, the gate electrode of the MOS tube, the other end of the resistor R36, and the negative pole of the electrolytic capacitor C15 are connected with the IC control unit; the other end of the resistor R27 is connected with one end of the resistor R28, and the other end of the resistor R28 and the other end of the capacitor CY4 are grounded; the other end of the resistor R19 is connected with the input end of the feedback module and the No. 4 pin of the common-mode inductor LF4; the No. 2 pin of the common-mode inductor LF4 is used for outputting a positive voltage, and the No. 3 pin of the common-mode inductor LF4 is used for outputting a negative voltage.

[0032] In the embodiment, as Figure 6As shown, the IC control unit comprises resistance R13, resistance R38, IC control chip U2, resistance R85, resistance R88, resistance R87, capacitor C22, resistance R82, resistance R83, resistance R84, capacitor C20, IC control chip U2 is TEA1995T; the No. 5 pin of IC control chip U2 is connected with one end of resistance R88 and one end of resistance R87; the other end of resistance R87 is grounded; the other end of resistance R88 is connected with the other end of resistance R11; the No. 6 pin of IC control chip U2 is connected with one end of resistance R85; the other end of resistance R85 is connected with the drain of MOS tube Q6; the No. 7 pin of IC control chip U2 is connected with one end of capacitor C20; the No. 8 pin of IC control chip U2 is connected with one end of resistance R13; the other end of resistance R13 is connected with the other end of resistance R30 and the gate of MOS tube Q6; the No. 2 pin of IC control chip U2 is connected with the other end of capacitor C20, one end of resistance R83 and the negative pole of electrolytic capacitor C15; the No. 3 pin of IC control chip U2 is connected with one end of capacitor C22 and one end of resistance R82; the other end of capacitor C22, the other end of resistance R82 and one end of resistance R84 are all connected with the other end of capacitor C16; the No. 4 pin of IC control chip U2 is connected with the other end of resistance R83 and the other end of resistance R84; the No. 1 pin of IC control chip U2 is connected with one end of resistance R38; the other end of resistance R38 is connected with the other end of resistance R36 and the gate of MOS tube Q8.

[0033] In the present embodiment, as Figure 7As shown, the feedback module includes an optocoupler IC1, a capacitor C39, a resistor R58, a resistor R80, a diode ZD1, a resistor R52, a resistor R51, a capacitor C32, a capacitor C33, a resistor R62, a voltage reference chip U6, a resistor R66, and a resistor R65; the voltage reference chip U6 is ME431AXG; the optocoupler IC1 includes an optocoupler input unit IC1B and an optocoupler output unit IC1A; pin 1 of the optocoupler input unit IC1B is connected to one end of the resistor R51 and one end of the resistor R80; one end of the resistor R80 is connected to the positive electrode of the diode ZD1; the negative electrode of the diode ZD1 is connected to one end of the resistor R52; the other end of the resistor R52 is connected to one end of the capacitor C32 and the resistor R66. One end of capacitor C33, one end of resistor R65, one end of resistor R66, and the reference of voltage reference chip U6 are all connected; the anode of voltage reference chip U6, the other end of resistor R65, and the other end of resistor R66 are all grounded; the other end of capacitor C33 is connected to one end of resistor R62; the other end of resistor R62, the other end of capacitor C32, the other end of resistor R51, and pin 2 of optocoupler input unit IC1B are all connected to the other end of resistor R19; pin 4 of optocoupler output unit IC1A and one end of capacitor C39 are all connected to pin 16 of combination control chip U1; pin 3 of optocoupler output unit IC1A is connected to one end of resistor R58; the other end of resistor R58 and the other end of capacitor C39 are all grounded.

[0034] The working principle of a low-voltage power adapter circuit in this embodiment is as follows:

[0035] Input module: The input module receives AC input (such as mains power). Fuse F1 provides overcurrent protection, varistor MOV1 suppresses surge voltage, common-mode inductors LF3 and LF1 filter out electromagnetic interference, and rectifier BD1 converts AC to pulsating DC. Capacitors C1 and C2 and PFC inductor L2 perform preliminary filtering and energy storage. This power is ultimately delivered to the input of the active PFC module and LCC resonant module, providing a foundation for subsequent conversion. This ensures stable and safe input power.

[0036] Active PFC module: The active PFC module is divided into input part, transformer part and control part. The input part contains MOS tube Q4 and MOS tube Q5, which are driven by control chip U1 (TEA2016AAT) to realize voltage conversion and improve power factor. Specifically, the input DC voltage is converted to high-frequency oscillation in the resonant inductor L3 and transformer T1 through the switching action of MOS tube Q4 / MOS tube Q5, and the voltage is lifted and stabilized. The control part (control chip U1) monitors the input and output parameters, adjusts the switching frequency of MOS tube Q4 / MOS tube Q5 through pins (such as 5 pins, 6 pins, 9 pins), and ensures that the power factor is close to 1. The transformer part (T1) transmits energy to the output module, in which diode D5 / diode D6 and voltage stabilizing elements (such as D13) provide rectification and overvoltage protection. The purpose is to reduce input current harmonics and improve overall efficiency.

[0037] LCC resonance module: The LCC resonance module uses LCC resonance topology (inductor-capacitor-capacitor resonance) to realize soft switching and reduce switching loss. The LCC resonance module includes MOS tube Q1, MOS tube Q2, MOS tube Q3, and MOS tube Q7, as well as resonant capacitor C6 and PFC inductor L2. When the output signal of the active PFC module is input, MOS tube Q1, MOS tube Q2, MOS tube Q3, and MOS tube Q7 switch under the control of the control signal (from the 5th and 8th pins of the combined control chip U1), and a resonant waveform is generated in the resonant cavity (such as capacitor C6 and resistor R18). The purpose is to achieve zero-voltage switching (ZVS) or zero-current switching (ZCS), thereby reducing switching noise and energy loss. At the same time, triode Q7 and resistor network (R15 / R16) provide auxiliary control to ensure the stability of the resonant frequency.

[0038] Output module: The output module is composed of an output unit and an IC control unit, which is responsible for outputting the converted energy as stable DC. The output unit uses electrolytic capacitor C15, electrolytic capacitor C17, and electrolytic capacitor C18 for filtering, and MOS tube Q6 and MOS tube Q8 as synchronous rectifiers to improve rectification efficiency. The core of the IC control unit is IC control chip U2 (TEA1995T), which monitors the output current and voltage through pins (such as 5 pins, 6 pins, 8 pins) and drives the gate of MOS tube Q6 / MOS tube Q8 to realize precise switching control. Among them, the 2nd and 4th pins of IC control chip U2 are connected to capacitor C20 and resistor R83, providing feedback compensation to ensure that the output voltage (outputting positive and negative voltages through common-mode inductor LF4) is stable at the set value, thereby reducing conduction loss and improving output quality.

[0039] The feedback module samples the output signal in real time and uses optocoupler IC1 (including IC1B and IC1A) and voltage reference chip U6 (ME431AXG) for isolated feedback. Specifically, the output signal is sampled through the resistor network (R51 / R52) and diode ZD1, and then input to the reference end of the voltage reference chip U6. The voltage reference chip U6 compares the reference voltage and outputs an error signal. The optocoupling input unit IC1B of the optocoupler IC1 transmits the error signal to the optocoupling output unit IC1A through optical coupling isolation. The optocoupling output unit IC1A of the optocoupler IC1 outputs (connected to pin 16 of the combination control chip U1) the control parameters of the active PFC module and the LCC resonant module. The purpose is to form a closed-loop control, so as to achieve the purpose of keeping the output voltage constant even if the input or load changes.

[0040] On the one hand, through the soft switching technology of the LCC resonant module, the switching loss and heat dissipation are effectively reduced. At the same time, combined with the power factor correction of the active PFC module, the overall energy efficiency is effectively improved, and the energy utilization rate of the power adapter is improved. On the other hand, the feedback module provides fast response and isolated feedback, combined with the synchronous rectification of the output module, effectively reduces the fluctuation of the output voltage, and ensures the stability of the load regulation rate and linear regulation.

[0041] Although the present application has been described herein with reference to the various illustrative embodiments thereof, those of ordinary skill in the art will appreciate that many modifications and variations are possible in light of the above teachings and within the scope and spirit of the application. More specifically, many variations and modifications can be made to the above-described subject combination layout, to its constituent components, and / or to the layout itself, without departing from the scope or spirit of the application. Other uses will also become apparent to those of ordinary skill in the art.

Claims

1. A low voltage power supply adaptation circuit, characterized by It comprises: an input module for connecting an input power supply; an active PFC module, the input end of which is connected with the output end of the input module; an LCC resonant module, the input end of which is connected with the output end of the input module, and which is connected with the active PFC module; an output module, the input end of which is connected with the output end of the active PFC module; a feedback module, the input end of which is connected with the output end of the output module, and the output end of which is connected with the active PFC module.

2. The low-voltage power supply adaptation circuit according to claim 1, wherein: the input module comprises a fuse F1, a capacitor CX2, a voltage-dependent resistor MOV1, a common-mode inductor LF3, a capacitor CY2, a capacitor CY3, a capacitor CX1, a common-mode inductor LF1, a rectifier BD1, a magnetic ring magnetic core L1, a capacitor C2, a PFC inductor L2, a diode D1, a thermistor RT1, a resistor R5, a resistor R6, and a capacitor C4; one end of the fuse F1 is used for connecting an L pole of the input power supply; the other end of the fuse F1 is connected with one end of the capacitor CX2, one end of the voltage-dependent resistor MOV1, and a No. 2 pin of the common-mode inductor LF3; the other end of the capacitor CX2, the other end of the voltage-dependent resistor MOV1, and a No. 3 pin of the common-mode inductor LF3 are used for connecting an N pole of the input power supply; a No. 1 pin of the common-mode inductor LF3 is connected with one end of the capacitor CY2, one end of the capacitor CX1, and a No. 2 pin of the common-mode inductor LF1; a No. 4 pin of the common-mode inductor LF3 is connected with one end of the capacitor CY3, the other end of the capacitor CX1, and a No. 3 pin of the common-mode inductor LF1; the other end of the capacitor CY2 and the other end of the capacitor CY3 are grounded; a No. 1 pin of the common-mode inductor LF1 is connected with a No. 2 pin of the rectifier BD1; a No. 4 pin of the common-mode inductor LF1 is connected with a No. 3 pin of the rectifier BD1; a No. 1 pin of the rectifier BD1 is connected with one end of the magnetic ring magnetic core L1, a positive electrode of the diode D1, and one end of the capacitor C1; the other end of the capacitor C1 is connected with one end of the capacitor C2; the other end of the magnetic ring magnetic core L1 and the other end of the capacitor C2 are connected with a No. 1 pin of the PFC inductor L2; a No. 3 pin of the PFC inductor L2 is connected with one end of the capacitor C4 and the input end of the LCC resonant module; a negative electrode of the diode D1 is connected with one end of the thermistor RT1; the other end of the thermistor RT1 is connected with one end of the resistor R5, one end of the resistor R6, and the input end of the active PFC module; the other end of the resistor R5 and one end of the resistor R6 are connected with the other end of the capacitor C4.

3. The low-voltage power supply adaptation circuit according to claim 2, wherein: the active PFC module comprises an input part, a transformation part, and a control part; the input part comprises an electrolytic capacitor C3, a capacitor C44, a MOS tube Q4, a capacitor C9, a diode D3, a resistor R48, a resistor R8, a resistor R9, a resonant inductor L3, a MOS tube Q5, a capacitor C12, a resistor R32, a resistor R49, a resistor R31, and a capacitor C13. The drain of the MOS tube Q4 is connected with one end of the capacitor C9, one end of the capacitor C44, the positive pole of the electrolytic capacitor C3, the other end of the thermistor RT1, and the output end of the LCC resonant module; The negative pole of the electrolytic capacitor C3 and the other end of the capacitor C44 are grounded; The source of the MOS tube Q4 is connected with the other end of the capacitor C9, one end of the resistor R48, one end of the resonant inductor L3, one end of the capacitor C12, the drain of the MOS tube Q5, and the control part; The other end of the resonant inductor L3 is connected with the input end of the transformation part; The output end of the transformation part is connected with the input end of the output module; The gate of the MOS tube Q4 is connected with the other end of the resistor R48, the positive pole of the diode D3, and one end of the resistor R8; The other end of the resistor R8 and the negative pole of the diode D3 are connected with one end of the resistor R9; The other end of the resistor R9 is connected with the control part; The source of the MOS tube Q5, the other end of the capacitor C12, one end of the capacitor C13, and one end of the resistor R49 are grounded; The other end of the capacitor C13 is connected with the input end of the transformation part and the control part; The gate of the MOS tube Q5 is connected with the other end of the resistor R49, one end of the resistor R32, and the positive pole of the diode D4; The negative pole of the diode D4 and the other end of the resistor R32 are connected with one end of the resistor R31; The other end of the resistor R31 is connected with the control part.

4. The low-voltage power supply adaptation circuit according to claim 3, characterized in that: the transformation part comprises a transformer T1, a diode D5, a diode D6, a resistor R47, an electrolytic capacitor C51, a voltage stabilizing diode D13, a resistor R50, a triode Q10, a resistor R10, a resistor R45, a capacitor C30, and an electrolytic capacitor C29; the transformer T1 comprises a first transformation unit T1A and a second transformation unit T1B; the No. 2 pin of the first transformation unit T1A is connected with the other end of the resonant inductor L3; the No. 1 pin of the first transformation unit T1A is connected with the other end of the capacitor C13; the No. 8 pin of the first transformation unit T1A, the No. 9 pin of the first transformation unit T1A, the No. 10 pin of the first transformation unit T1A, and the No. 12 pin of the first transformation unit T1A are all connected with the input end of the output module; the No. 3 pin of the second transformation unit T1B is grounded; the No. 5 pin of the second transformation unit T1B is connected with the positive pole of the diode D5; the No. 6 pin of the second transformation unit T1B is connected with the positive pole of the diode D6; the negative pole of the diode D5 and the negative pole of the diode D6 are connected with one end of the resistor R47; the other end of the resistor R47 is connected with the positive pole of the electrolytic capacitor C51, one end of the resistor R50, the collector of the triode Q10, and one end of the resistor R10; the negative pole of the electrolytic capacitor C51 and the positive pole of the voltage stabilizing diode D13 are grounded; the negative pole of the voltage stabilizing diode D13 and the other end of the resistor R50 are connected with the base of the triode Q10; the emitter of the triode Q10 is connected with the other end of the resistor R10, one end of the resistor R45, and the positive pole of the electrolytic capacitor C29; the other end of the resistor R45 is connected with one end of the capacitor C30; The other end of the capacitor C30 and the negative pole of the electrolytic capacitor C29 are connected to ground.

5. The low-voltage power supply adaptation circuit according to claim 4, characterized in that: The control part comprises a combination control chip U1, a diode D10, a capacitor C25, a resistor R33, a resistor R34, a capacitor C11, a capacitor C10, a capacitor C26, a resistor R46, a capacitor C24, a capacitor C28, a resistor R44, and a capacitor C27. The combination control chip U1 is TEA2016AAT_SO-16. The No. 5 pin of the combination control chip U1 is connected to the input end of the LCC resonant module. The No. 6 pin of the combination control chip U1 is connected to the other end of the resistor R31. The No. 8 pin of the combination control chip U1 is connected to the input end of the LCC resonant module. The No. 9 pin of the combination control chip U1 is connected to the other end of the resistor R9. The No. 10 pin of the combination control chip U1 is connected to one end of the capacitor C25 and the negative pole of the diode D10. The positive pole of the diode D10 is connected to the other end of the resistor R31. The No. 11 pin of the combination control chip U1 is connected to the other end of the capacitor C25 and the source of the MOS tube Q4. The No. 14 pin of the combination control chip U1 is connected to one end of the resistor R44, one end of the resistor R34, one end of the capacitor C11, one end of the capacitor C28, and one end of the capacitor C24. The other end of the resistor R44, the other end of the capacitor C28, and the other end of the capacitor C24 are connected to ground. The other end of the resistor R34 is connected to one end of the resistor R33. The other end of the resistor R33, the other end of the capacitor C11, and one end of the capacitor C10 are connected to the other end of the capacitor C13. The No. 15 pin of the combination control chip U1 is connected to one end of the capacitor C27. The other end of the capacitor C27 is connected to one end of the resistor R46, the other end of the capacitor C10, and one end of the capacitor C26. The other end of the capacitor C26 and the other end of the resistor R46 are connected to ground. The No. 16 pin of the combination control chip U1 is connected to the output end of the feedback module.

6. The low-voltage power supply adaptation circuit according to claim 5, characterized in that: The LCC resonant module comprises a diode D2, a MOS tube Q1, a MOS tube Q2, a triode Q1, a resistor R2, a resistor R3, a resistor R4, a resistor R15, a resistor R16, a triode Q7, a resistor R35, a capacitor C41, a resistor R37, a resistor R17, a resistor R20, a resistor R18, a capacitor C6, a resistor R14, and a resistor R1. The negative pole of the diode D2 is connected to the other end of the thermistor RT1. The drain of the MOS tube is connected to the positive pole of the diode D2. The gate of the MOS tube is connected to one end of the resistor R2 and the emitter of the triode Q1. The source of the MOS tube, one end of the resistor R4, one end of the resistor R17, one end of the resistor R35, one end of the resistor R37, one end of the resistor R20, one end of the capacitor C6, and the source of the MOS tube Q3 are connected to ground. The collector of the triode Q1 is connected to the other end of the resistor R4. The base of the triode Q1 is connected to one end of the resistor R3. The other end of the resistor R3, the other end of the resistor R2, one end of the resistor R15, and one end of the resistor R16 are connected to one end of the resistor R14; The other end of the resistor R14 is connected to pin 5 of the combination control chip U1; The other end of the resistor R15 is connected to the emitter of the transistor Q7, the gate of the MOS tube Q3, and the other end of the resistor R35; The drain of the MOS tube Q3, one end of the capacitor C41, and one end of the resistor R1 are connected to pin 3 of the PFC inductor L2; The other end of the capacitor C41 is connected to the other end of the resistor R37; The other end of the resistor R1 is connected to pin 8 of the combination control chip U1; The other end of the resistor R16 is connected to the base of the transistor Q7; The collector of the transistor Q7 is connected to the other end of the resistor R17; The other end of the resistor R20 is connected to one end of the resistor R18; The other end of the resistor R18 is connected to the other end of the capacitor C6.

7. The low-voltage power supply adaptation circuit of claim 6, wherein: the output module comprises an output unit and an IC control unit; the output unit comprises a capacitor CY5, a capacitor CY1, a capacitor C5, a resistor R11, a MOS tube Q6, a resistor R30, a capacitor C16, a resistor R12, a MOS tube Q8, a resistor R36, an electrolytic capacitor C15, an electrolytic capacitor C17, an electrolytic capacitor C18, a capacitor CY4, a resistor R27, a resistor R28, a resistor R19, a capacitor C31, and a common-mode inductor LF4; one end of the capacitor CY5 is connected to the positive pole of the electrolytic capacitor C15, the positive pole of the electrolytic capacitor C17, the positive pole of the electrolytic capacitor C18, one end of the capacitor C31, pin 1 of the common-mode inductor LF4, pin 8 of the first transformer unit T1A, and pin 9 of the first transformer unit T1A; the other end of the capacitor CY5 is connected to one end of the capacitor CY1, and the other end of the capacitor CY1 is grounded; pin 10 of the first transformer unit T1A is connected to one end of the capacitor C5, and the other end of the capacitor C5 is connected to one end of the resistor R11; the other end of the resistor R11 is connected to the source of the MOS tube Q6, one end of the resistor R30, one end of the resistor R12, the IC control unit, one end of the resistor R36, the source of the MOS tube Q8, the negative pole of the electrolytic capacitor C17, the negative pole of the electrolytic capacitor C18, one end of the resistor R19, one end of the capacitor CY4, one end of the resistor R27, and the other end of the capacitor C31, and the other end of the resistor R11 is grounded; the other end of the resistor R12 is connected to one end of the capacitor C16, and the other end of the capacitor C16 is connected to the drain of the MOS tube Q8, the IC control unit, and pin 12 of the first transformer unit T1A; the drain of the MOS tube Q6, the gate of the MOS tube Q6, the other end of the resistor R30, the gate of the MOS tube, the other end of the resistor R36, and the negative pole of the electrolytic capacitor C15 are connected to the IC control unit; the other end of the resistor R27 is connected to one end of the resistor R28, and the other end of the resistor R28 and the other end of the capacitor CY4 are grounded; the other end of the resistor R19 is connected to the input end of the feedback module and pin 4 of the common-mode inductor LF4. The pin 2 of the common mode inductor LF4 is used for outputting positive voltage, and the pin 3 of the common mode inductor LF4 is used for outputting negative voltage.

8. The low-voltage power supply adaptation circuit according to claim 7, characterized in that: The IC control unit comprises a resistor R13, a resistor R38, an IC control chip U2, a resistor R85, a resistor R88, a resistor R87, a capacitor C22, a resistor R82, a resistor R83, a resistor R84, a capacitor C20, The IC control chip U2 is TEA1995T; The pin 5 of the IC control chip U2 is connected with one end of the resistor R88 and one end of the resistor R87; The other end of the resistor R87 is grounded; The other end of the resistor R88 is connected with the other end of the resistor R11; The pin 6 of the IC control chip U2 is connected with one end of the resistor R85; The other end of the resistor R85 is connected with the drain of the MOS tube Q6; The pin 7 of the IC control chip U2 is connected with one end of the capacitor C20; The pin 8 of the IC control chip U2 is connected with one end of the resistor R13; The other end of the resistor R13 is connected with the other end of the resistor R30 and the gate of the MOS tube Q6; The pin 2 of the IC control chip U2 is connected with the other end of the capacitor C20, one end of the resistor R83 and the negative electrode of the electrolytic capacitor C15; The pin 3 of the IC control chip U2 is connected with one end of the capacitor C22 and one end of the resistor R82; The other end of the capacitor C22, the other end of the resistor R82 and one end of the resistor R84 are all connected with the other end of the capacitor C16; The pin 4 of the IC control chip U2 is connected with the other end of the resistor R83 and the other end of the resistor R84; The pin 1 of the IC control chip U2 is connected with one end of the resistor R38; The other end of the resistor R38 is connected with the other end of the resistor R36 and the gate of the MOS tube Q8.

9. The low-voltage power supply adaptation circuit according to claim 8, characterized in that: The feedback module comprises an opto-coupler IC1, a capacitor C39, a resistor R58, a resistor R80, a diode ZD1, a resistor R52, a resistor R51, a capacitor C32, a capacitor C33, a resistor R62, a voltage reference chip U6, a resistor R66, a resistor R65; The voltage reference chip U6 is ME431AXG; The opto-coupler IC1 comprises an opto-coupling input unit IC1B and an opto-coupling output unit IC1A; The pin 1 of the opto-coupling input unit IC1B is connected with one end of the resistor R51 and one end of the resistor R80; One end of the resistor R80 is connected with the positive electrode of the diode ZD1; The negative electrode of the diode ZD1 is connected with one end of the resistor R52; The other end of the resistor R52 is connected with one end of the capacitor C32, one end of the capacitor C33, one end of the resistor R65, one end of the resistor R66 and the reference of the voltage reference chip U6; The anode of the voltage reference chip U6, the other end of the resistor R65 and the other end of the resistor R66 are all grounded; The other end of the capacitor C33 is connected with one end of the resistor R62; The other end of the capacitor C33 is connected with one end of the resistor R62. The other end of the resistor R62, the other end of the capacitor C32, the other end of the resistor R51 and the 2nd pin of the photoelectric coupling input unit IC1B are connected with the other end of the resistor R19; The 4th pin of the photoelectric coupling output unit IC1A and one end of the capacitor C39 are connected with the 16th pin of the combination control chip U1; The 3rd pin of the photoelectric coupling output unit IC1A is connected with one end of the resistor R58; The other end of the resistor R58 and the other end of the capacitor C39 are grounded.

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