A power supply circuit for a rechargeable battery

Abstract

This utility model relates to the field of charging power supply technology, and discloses a power supply circuit for a rechargeable battery, comprising: a rectifier and filter circuit, a transformer circuit, a PWM control circuit, and a feedback voltage circuit. The input terminal of the rectifier and filter circuit is connected to an external AC power supply, and the output terminal of the rectifier and filter circuit is connected to the input terminal of the transformer circuit. One output terminal of the transformer circuit is connected to the input terminal of the PWM control circuit, and the other output terminal of the transformer circuit is connected to the feedback terminal of the feedback voltage circuit and an external power supply. The feedback control terminal of the PWM control circuit is connected to the feedback control terminal of the feedback voltage circuit, and the output terminal of the PWM control circuit is connected to the input terminal of the transformer circuit. This power supply circuit can realize feedback correction of the charging state of the battery, making charging safer. The cooperation between the PWM control circuit and the feedback voltage circuit can achieve charging feedback correction, which can effectively increase the battery's service life.

Description

Technical Field

[0001] This utility model relates to the field of charging power supply technology, specifically to a power supply circuit for a rechargeable battery. Background Technology

[0002] A switching power supply, also known as a switching converter or switching power supply unit, is a high-frequency power conversion device and a type of power supply. Its function is to convert a voltage at a certain level into the voltage or current required by the user through different structural forms. The input of a switching power supply is mostly AC power (such as mains power) or DC power, while the output is mostly for devices that require DC power, such as personal computers and mobile phones. The switching power supply performs the voltage and current conversion between these two sources.

[0003] However, existing switching power supplies on the market do not effectively feed back the output power signal to the primary winding of the transformer to correct the charging state.

[0004] Therefore, existing power supply methods need further improvement to address the above issues. Utility Model Content

[0005] The purpose of this invention is to overcome the problems of existing charging systems lacking feedback correction of the charging state. By rationally designing the charging circuit and employing the cooperation of a rectifier filter circuit, a transformer circuit, a PWM control circuit, and a feedback voltage circuit, feedback correction of the battery charging state can be achieved, making charging safer.

[0006] The specific technical solution of this utility model is as follows:

[0007] A power supply circuit for a rechargeable battery includes: a rectifier and filter circuit, a transformer circuit, a PWM control circuit, and a feedback voltage circuit. The input terminal of the rectifier and filter circuit is connected to an external AC power supply, the output terminal of the rectifier and filter circuit is connected to the input terminal of the transformer circuit, one output terminal of the transformer circuit is connected to the input terminal of the PWM control circuit, the other output terminal of the transformer circuit is connected to the feedback terminal of the feedback voltage circuit and an external power supply, the feedback control terminal of the PWM control circuit is connected to the feedback control terminal of the feedback voltage circuit, and the output terminal of the PWM control circuit is connected to the input terminal of the transformer circuit.

[0008] The feedback voltage circuit includes an operational amplifier circuit and an optocoupler circuit. The feedback terminal of the operational amplifier circuit is connected to the other output terminal of the transformer circuit, the output terminal of the operational amplifier circuit is connected to the input terminal of the optocoupler circuit, and the output terminal of the optocoupler circuit is connected to the feedback control terminal of the PWM control circuit.

[0009] Furthermore, the operational amplifier circuit is selected to include an operational amplifier circuit with two operational amplifiers.

[0010] Further, the operational amplifier circuit includes resistor R10, Zener diode U3, capacitors C12 and C7, resistor NC1, diode D3, resistors R11, R15, R14, R13, R12, NC2, diode D4, amplifier U4, capacitor C13, resistor R27, capacitor C11, resistor R23, resistor R22, resistor R31, capacitor C14, resistor R20, resistor R29, resistor R17, capacitor C8, NPN transistor Q2, resistors R28, R26, resistor R18, LED1, and amplifier U41. The input terminal of the optocoupler circuit is connected to one end of resistor R10, terminal "3" of Zener diode U3, and the positive terminal of diode D4. The other end of resistor R10 is connected to one end of capacitor C7. Terminal 2 of Zener diode U3 is grounded. Terminal 1 of Zener diode U3 is connected to one end of capacitor C12, the other end of capacitor C7, one end of resistor R11, one end of resistor R14, one end of resistor R15, and one end of resistor NC1. The other ends of capacitor C12, resistor NC1, and resistor R15 are all grounded. The other end of resistor R11 is connected to the anode of diode D3. The cathode of diode D3 is connected to one end of resistor R16. The other end of resistor R16 is connected to the collector of NPN transistor Q2. The emitter of NPN transistor Q2 is grounded. The base of NPN transistor Q2 is connected to one end of resistor R17. The other end of resistor R17 is connected to amplifier U41 "7". "Terminal, one end of capacitor C8 and one positive terminal of LED1, the collector of NPN transistor Q2 is connected to the other positive terminal of LED1, the negative terminal of LED1 is connected to one end of resistor R28, the other end of resistor R28 is grounded, the other end of resistor R14 is connected to one end of resistor R13, the other end of resistor R13 is connected to one end of resistor R12 and one end of resistor NC2, the other ends of resistor R12 and resistor NC2 are connected to an external DC power supply, the other end of capacitor C8 is connected to terminal 6 of amplifier U41, one end of resistor R18 and one end of resistor R26, the other end of resistor R18 is grounded, the other end of resistor R26 is connected to an external DC power supply, the negative terminal of diode D4 is connected to terminal 1 of amplifier U4 and one end of resistor R27, the resistor..." The other end of R27 is connected to one end of capacitor C11. The other end of capacitor C11 is connected to one end of resistor R31 and terminal "2" of amplifier U4. The other end of resistor R31 is connected to one end of resistor R29, one end of capacitor C14, and one end of resistor R20. The other end of resistor R20 is connected to the output terminal of the transformer circuit. The other end of capacitor C14 is grounded. The other end of resistor R29 is connected to terminal "5" of amplifier U41. Terminal "8" of amplifier U4 and one end of capacitor C13 are connected to an external DC power supply. The other end of capacitor C13 is grounded. Terminal "4" of amplifier U4 is grounded. Terminal "3" of amplifier U4 is connected to one end of resistor R23 and one end of resistor R22. The other end of resistor R22 is grounded. The other end of resistor R23 is connected to an external DC power supply.

[0011] Furthermore, the optocoupler circuit includes an optocoupler U2 and a resistor R9. The "3" and "4" terminals of the optocoupler U2 are respectively connected to the feedback control terminal of the PWM control circuit. The "1" terminal of the optocoupler U2 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to an external DC power supply. The "2" terminal of the optocoupler U2 is connected to the output terminal of the operational amplifier circuit.

[0012] Furthermore, the rectifier and filter circuit includes a fuse F1, a thermistor NTC1, a rectifier bridge DP1, and a capacitor E1. One end of the fuse F1 is connected to the live wire of the AC power supply, and the other end of the fuse F1 is connected to terminal "3" of the rectifier bridge DP1. One end of the thermistor NTC1 is connected to the neutral wire of the AC power supply, and the other end of the thermistor NTC1 is connected to terminal "1" of the rectifier bridge DP1. Terminal "2" of the rectifier bridge DP1 is grounded. Terminal "4" of the rectifier bridge DP1 is connected to one end of the capacitor E1 and the input terminal of the transformer circuit, and the other end of the capacitor E1 is grounded.

[0013] Furthermore, the transformer circuit includes a primary transformer circuit, a first-stage transformer circuit, a second-stage transformer circuit, and a third-stage transformer circuit. The input terminal of the primary transformer circuit is connected to the output terminal of the rectifier and filter circuit. The output terminal of the primary transformer circuit is connected to the input terminals of the first-stage transformer circuit, the second-stage transformer circuit, and the third-stage transformer circuit, respectively. The output terminal of the first-stage transformer circuit is connected to the input terminal of the PWM control circuit. The output terminals of the second-stage transformer circuit and the third-stage transformer circuit serve as external power outputs.

[0014] Furthermore, the primary transformer circuit includes a transformer T1, a resistor R2, a capacitor C1, and a diode D1. The "3" terminal of the transformer T1 is connected to one end of the resistor R2, one end of the capacitor C1, and the output terminal of the rectifier filter circuit. The other end of the resistor R2 is connected to the other end of the capacitor C1 and the negative terminal of the diode D1. The positive terminal of the diode D1 is connected to the "1" terminal of the transformer T1.

[0015] Furthermore, the primary transformer circuit includes a resistor R3, one end of which is connected to terminal "4" of the transformer T1, and the other end of which is connected to the input terminal of the PWM control circuit. Terminal "6" of the transformer T1 is grounded.

[0016] Furthermore, the secondary transformer circuit includes capacitor C10, resistor R30, diode D7, and capacitor E4. The "12" terminal of transformer T1 is connected to one end of capacitor C10 and the positive terminal of diode D7. The other end of capacitor C10 is connected to one end of resistor R30. The other end of resistor R30 is connected to the negative terminal of diode D7, one end of capacitor E4, and the external output power supply. The "10" terminal of transformer T1 and the other end of capacitor E4 are grounded together.

[0017] Furthermore, the third-stage transformer circuit includes a diode D6, a capacitor E3, and a resistor R24. The "7" terminal of the transformer T1 is connected to the positive terminal of the diode D6, the negative terminal of the diode D6, one end of the capacitor E3, and one end of the resistor R24. The other end of the capacitor E3 is grounded, and the other end of the resistor R24 ​​is connected to the external output power supply. The "9" terminal of the transformer T1 is grounded.

[0018] Further, the PWM control circuit includes resistor R4, capacitors C3, C4, C2, C5, chip U1, resistor R36, diode D2, resistor R1, capacitor E2, resistor R5, resistor R6, NMOS transistor Q1, resistor R7, resistor R8, and capacitor C6. Terminal "1" of chip U1 is connected to one end of capacitor C5 and the feedback control terminal of the feedback voltage circuit; the other end of capacitor C5 is grounded. Terminal "2" of chip U1 is grounded, terminal "5" of chip U1 is grounded, terminal "4" of chip U1 is connected to one end of capacitor C4 and one end of resistor R4; the other end of capacitor C4 is grounded. The other end of resistor R4 is connected to terminal "8" of chip U1 and one end of capacitor C3; the other end of capacitor C3 is grounded. Terminal "4" of chip U1... The capacitor C2 is connected to one end of the resistor R36. The other end of the capacitor C2 is grounded. The other end of the resistor R36 is connected to one end of the capacitor E2, one end of the resistor R1, and the negative terminal of the diode D2. The other end of the capacitor E2 is grounded. The positive terminal of the diode D2 is connected to the output terminal of the transformer circuit. The other end of the resistor R1 is connected to the output terminal of the rectifier and filter circuit. The "6" terminal of the chip U1 is connected to one end of the resistor R5. The other end of the resistor R5 is connected to the gate of the NMOS transistor Q1 and one end of the resistor R7. The "3" terminal of the chip U1 is connected to one end of the capacitor C6 and one end of the resistor R6. The other end of the resistor R6 is connected to one end of the resistor R8 and the source of the NMOS transistor Q1. The other ends of the capacitor C6, the other ends of the resistor R7, and the other ends of the resistor R8 are all grounded. The drain of the NMOS transistor Q1 is connected to the input terminal of the transformer circuit.

[0019] Furthermore, the rectifier bridge DP1 is selected as the BP410G model rectifier bridge DP1.

[0020] Furthermore, the chip U1 is selected as the UC3845 model chip.

[0021] Beneficial effects

[0022] This invention, through a rational design of the charging circuit, employs the coordinated use of a rectifier filter circuit, a transformer circuit, a PWM control circuit, and a feedback voltage circuit to achieve charging state correction and enhance charging safety. The combined use of the PWM control circuit and the feedback voltage circuit effectively increases battery life by providing charging feedback correction. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the power supply circuit of a rechargeable battery according to the present invention.

[0024] Figure 2 This is a schematic diagram of the power supply circuit of a rechargeable battery according to the present invention.

[0025] Reference numerals: 01, Rectifier and filter circuit; 02, Transformer circuit; 03, PWM control circuit; 04, Feedback voltage circuit. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] See Figures 1-2 As shown, the present invention provides a power supply circuit for a rechargeable battery. The power supply circuit for the rechargeable battery includes: a rectifier and filter circuit 01, a transformer circuit 02, a PWM control circuit 03, and a feedback voltage circuit 04. The input terminal of the rectifier and filter circuit 01 is connected to an external AC power supply, and the output terminal of the rectifier and filter circuit 01 is connected to the input terminal of the transformer circuit 02. One output terminal of the transformer circuit 02 is connected to the input terminal of the PWM control circuit 03, and the other output terminal of the transformer circuit 02 is connected to the feedback terminal of the feedback voltage circuit 04 and the external power supply. The feedback control terminal of the PWM control circuit 03 is connected to the feedback control terminal of the feedback voltage circuit 04, and the output terminal of the PWM control circuit 03 is connected to the input terminal of the transformer circuit 02.

[0028] The feedback voltage circuit 04 includes an operational amplifier circuit and an optocoupler circuit. The feedback terminal of the operational amplifier circuit is connected to the other output terminal of the transformer circuit 02, the output terminal of the operational amplifier circuit is connected to the input terminal of the optocoupler circuit, and the output terminal of the optocoupler circuit is connected to the feedback control terminal of the PWM control circuit 03.

[0029] Among them, the operational amplifier circuit is selected to include an operational amplifier circuit with two operational amplifiers;

[0030] The transformer circuit 02 includes a primary transformer circuit, a first-stage transformer circuit, a second-stage transformer circuit, and a third-stage transformer circuit. The input terminal of the primary transformer circuit is connected to the output terminal of the rectifier and filter circuit 01. The output terminal of the primary transformer circuit is connected to the input terminals of the first-stage transformer circuit, the second-stage transformer circuit, and the third-stage transformer circuit, respectively. The output terminal of the first-stage transformer circuit is connected to the input terminal of the PWM control circuit 03. The output terminals of the second-stage transformer circuit and the third-stage transformer circuit serve as external power outputs.

[0031] The rectifier and filter circuit 01 includes a fuse F1, a thermistor NTC1, a rectifier bridge DP1, and a capacitor E1; the primary transformer circuit 02 includes a transformer T1, a resistor R2, a capacitor C1, and a diode D1; the first-stage transformer circuit 02 includes a resistor R3; the second-stage transformer circuit 02 includes a capacitor C10, a resistor R30, a diode D7, and a capacitor E4; the third-stage transformer circuit 02 includes a diode D6, a capacitor E3, and a resistor R24; the optocoupler circuit includes an optocoupler U2 and a resistor R9; and the PWM control circuit 03 includes a resistor R4, capacitors C3, C4, C2, and C5, a chip U1, a resistor R36, a diode D2, and a resistor R1. The components include: capacitor E2, resistors R5 and R6, NMOS transistor Q1, resistors R7 and R8, and capacitor C6; the operational amplifier circuit includes resistor R10, Zener diode U3, capacitors C12 and C7, resistor NC1, diode D3, resistors R11, R15, R14, R13, R12, and NC2, diode D4, amplifier U4, capacitor C13, resistors R27, C11, R23, R22, and R31, capacitor C14, resistors R20, R29, R17, capacitor C8, NPN transistor Q2, resistors R28, R26, and R18, LED1, and amplifier U41;

[0032] In this rectifier and filter circuit 01, one end of fuse F1 is connected to the live wire of the AC power supply, and the other end of fuse F1 is connected to the 3 terminal of rectifier bridge DP1. One end of thermistor NTC1 is connected to the neutral wire of the AC power supply, and the other end of thermistor NTC1 is connected to the 1 terminal of rectifier bridge DP1. The 2 terminal of rectifier bridge DP1 is grounded, and the 4 terminal of rectifier bridge DP1 is connected to one end of capacitor E1 and the 3 terminal of transformer T1 of transformer circuit 02. The other end of capacitor E1 is grounded.

[0033] In this primary transformer circuit, the transformer T1 "3" terminal is connected to one end of resistor R2, one end of capacitor C1, and the rectifier bridge DP1 "4" terminal of rectifier filter circuit 01. The other end of resistor R2 is connected to the other end of capacitor C1 and the negative terminal of diode D1. The positive terminal of diode D1 is connected to the transformer T1 "1" terminal. In the second-stage transformer circuit, one end of resistor R3 is connected to the transformer T1 "4" terminal, and the other end of resistor R3 is connected to the positive terminal of diode D2 of PWM control circuit 03. The transformer T1 "6" terminal is grounded. In the second-stage transformer circuit, the transformer T1 "12" terminal is connected to... Connect one end of capacitor C10 to the positive terminal of diode D7. Connect the other end of capacitor C10 to one end of resistor R30. Connect the other end of resistor R30 to the negative terminal of diode D7, one end of capacitor E4, and the external output power supply (positive terminal of JK2). Transformer T1 terminal "10" and the other end of capacitor E4 are grounded together. In the third stage transformer circuit, transformer T1 terminal "7" is connected to the positive terminal of diode D6. Connect one end of diode D6, capacitor E3, and one end of resistor R24. Connect the other end of capacitor E3 to ground. Connect the other end of resistor R24 ​​to the external output power supply (positive terminal of JK2). Transformer T1 terminal "9" is grounded.

[0034] In this PWM control circuit 03, terminal "1" of chip U1 is connected to one end of capacitor C5 and terminal "4" of optocoupler U2 of feedback voltage circuit 04. The other end of capacitor C5 is grounded. Terminal "2" of chip U1 is grounded. Terminal "5" of chip U1 is grounded. Terminal "4" of chip U1 is connected to one end of capacitor C4 and one end of resistor R4. The other end of capacitor C4 is grounded. The other end of resistor R4 is connected to terminal "8" of chip U1 and one end of capacitor C3. The other end of capacitor C3 is grounded. Terminal "4" of chip U1 is connected to one end of capacitor C2 and one end of resistor R36. The other end of capacitor C2 is grounded. The other end of resistor R36 is connected to one end of capacitor E2, one end of resistor R1, and diode. The negative terminal of diode D2 is connected to the other end of capacitor E2, the positive terminal of diode D2 is connected to the output terminal of transformer circuit 02, the other end of resistor R1 is connected to the rectifier bridge DP1 "4" terminal of rectifier filter circuit 01, the "6" terminal of chip U1 is connected to one end of resistor R5, the other end of resistor R5 is connected to the gate of NMOS transistor Q1 and one end of resistor R7, the "3" terminal of chip U1 is connected to one end of capacitor C6 and one end of resistor R6, the other end of resistor R6 is connected to one end of resistor R8 and the source of NMOS transistor Q1, the other ends of capacitor C6, resistor R7 and resistor R8 are all grounded, and the drain of NMOS transistor Q1 is connected to the positive terminal of diode D1 of transformer circuit 02.

[0035] In this optocoupler circuit, the optocoupler U2 "3" terminal is grounded, the optocoupler U2 "4" terminal is connected to the chip U1 "1" terminal of the PWM control circuit 03, the optocoupler U2 "1" terminal is connected to one end of the resistor R9, the other end of the resistor R9 is connected to the external DC power supply (+12V), and the optocoupler U2 "2" terminal is connected to the Zener diode U3 "3" terminal of the operational amplifier circuit.

[0036] In this operational amplifier circuit, the optocoupler U2's "2" terminal is connected to one end of resistor R10, the "3" terminal of Zener diode U3, and the positive terminal of diode D4. The other end of resistor R10 is connected to one end of capacitor C7. The "2" terminal of Zener diode U3 is grounded. The "1" terminal of Zener diode U3 is connected to one end of capacitor C12, the other end of capacitor C7, one end of resistor R11, one end of resistor R14, one end of resistor R15, and one end of resistor NC1. The other ends of capacitor C12, resistor NC1, and resistor R15 are all grounded. The other end of resistor R11 is connected to the positive terminal of diode D3. The cathode of diode D3 is connected to one end of resistor R16, and the other end of resistor R16 is connected to the collector of NPN transistor Q2. The emitter of NPN transistor Q2 is grounded. The base of NPN transistor Q2 is connected to one end of resistor R17, and the other end of resistor R17 is connected to terminal "7" of amplifier U41, one end of capacitor C8, and one positive terminal of LED1. The collector of NPN transistor Q2 is connected to the other positive terminal of LED1. The cathode of LED1 is connected to one end of resistor R28, and the other end of resistor R28 is grounded. The other end of resistor R14 is connected to one end of resistor R13, and the other end of resistor R13 is connected to one end of resistor R12. One end of resistor NC2 and the other end of resistor R12 are connected to an external DC power supply. The other end of capacitor C8 is connected to terminal 6 of amplifier U41, one end of resistor R18 and one end of resistor R26. The other end of resistor R18 is grounded, and the other end of resistor R26 is connected to an external DC power supply. The cathode of diode D4 is connected to terminal 1 of amplifier U4 and one end of resistor R27. The other end of resistor R27 is connected to one end of capacitor C11. The other end of capacitor C11 is connected to one end of resistor R31 and terminal 2 of amplifier U4. The other end of resistor R31 is connected to resistor R29. One end of capacitor C14 and one end of resistor R20 are connected to the external output power supply (negative terminal of JK2) of transformer circuit 02. The other end of capacitor C14 is grounded. The other end of resistor R29 is connected to terminal 5 of amplifier U41. Terminal 8 of amplifier U4 and one end of capacitor C13 are connected to the external DC power supply. The other end of capacitor C13 is grounded. Terminal 4 of amplifier U4 is grounded. Terminal 3 of amplifier U4 is connected to one end of resistor R23 and one end of resistor R22. The other end of resistor R22 is grounded. The other end of resistor R23 is connected to the external DC power supply.

[0037] Specifically, the rectifier bridge DP1 is selected as the BP410G model; the chip U1 is selected as the UC3845 model; and the Zener diode U3 is selected as the TL431 model.

[0038] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A power supply circuit for a rechargeable battery, characterized in that, The power supply circuit of the rechargeable battery includes: a rectifier and filter circuit, a transformer circuit, a PWM control circuit, and a feedback voltage circuit. The input terminal of the rectifier and filter circuit is connected to an external AC power supply, the output terminal of the rectifier and filter circuit is connected to the input terminal of the transformer circuit, one output terminal of the transformer circuit is connected to the input terminal of the PWM control circuit, the other output terminal of the transformer circuit is connected to the feedback terminal of the feedback voltage circuit and the external power supply, the feedback control terminal of the PWM control circuit is connected to the feedback control terminal of the feedback voltage circuit, and the output terminal of the PWM control circuit is connected to the input terminal of the transformer circuit. The feedback voltage circuit includes an operational amplifier circuit and an optocoupler circuit. The feedback terminal of the operational amplifier circuit is connected to the other output terminal of the transformer circuit, the output terminal of the operational amplifier circuit is connected to the input terminal of the optocoupler circuit, and the output terminal of the optocoupler circuit is connected to the feedback control terminal of the PWM control circuit.

2. The power supply circuit for a rechargeable battery according to claim 1, characterized in that, The operational amplifier circuit selected is an operational amplifier circuit containing two operational amplifiers.

3. The power supply circuit for a rechargeable battery according to claim 2, characterized in that, The operational amplifier circuit includes resistor R10, Zener diode U3, capacitors C12 and C7, resistor NC1, diode D3, resistors R11, R15, R14, R13, R12, NC2, diode D4, amplifier U4, capacitor C13, resistor R27, capacitor C11, resistor R23, resistor R22, resistor R31, capacitor C14, resistor R20, resistor R29, resistor R17, capacitor C8, NPN transistor Q2, resistor R28, resistor R26, resistor R18, LED1, and amplifier U41. The input terminal of the optocoupler circuit is connected to one end of resistor R10, terminal "3" of Zener diode U3, and the positive terminal of diode D4. The other end is connected to one end of capacitor C7. The "2" terminal of Zener diode U3 is grounded. The "1" terminal of Zener diode U3 is connected to one end of capacitor C12, the other end of capacitor C7, one end of resistor R11, one end of resistor R14, one end of resistor R15, and one end of resistor NC1. The other ends of capacitor C12, resistor NC1, and resistor R15 are all grounded. The other end of resistor R11 is connected to the anode of diode D3. The cathode of diode D3 is connected to one end of resistor R16. The other end of resistor R16 is connected to the collector of NPN transistor Q2. The emitter of NPN transistor Q2 is grounded. The base of NPN transistor Q2 is connected to one end of resistor R17. The other end of resistor R17 is connected to the "7" terminal of amplifier U41. One end of capacitor C8 is connected to one positive terminal of LED1. The collector of NPN transistor Q2 is connected to the other positive terminal of LED1. The negative terminal of LED1 is connected to one end of resistor R28, and the other end of resistor R28 is grounded. The other end of resistor R14 is connected to one end of resistor R13. The other end of resistor R13 is connected to one end of resistor R12 and one end of resistor NC2. The other ends of resistor R12 and NC2 are connected to an external DC power supply. The other end of capacitor C8 is connected to terminal U41"6 of amplifier, one end of resistor R18, and one end of resistor R26. The other end of resistor R18 is grounded, and the other end of resistor R26 is connected to an external DC power supply. The negative terminal of diode D4 is connected to terminal U4"1 of amplifier and one end of resistor R27.

27. The other end is connected to one end of capacitor C11. The other end of capacitor C11 is connected to one end of resistor R31 and the "2" terminal of amplifier U4. The other end of resistor R31 is connected to one end of resistor R29, one end of capacitor C14 and one end of resistor R20. The other end of resistor R20 is connected to the output terminal of transformer circuit. The other end of capacitor C14 is grounded. The other end of resistor R29 is connected to the "5" terminal of amplifier U41. The "8" terminal of amplifier U4 and one end of capacitor C13 are connected to an external DC power supply. The other end of capacitor C13 is grounded. The "4" terminal of amplifier U4 is grounded. The "3" terminal of amplifier U4 is connected to one end of resistor R23 and one end of resistor R22. The other end of resistor R22 is grounded. The other end of resistor R23 is connected to an external DC power supply.

4. The power supply circuit for a rechargeable battery according to claim 1, characterized in that, The optocoupler circuit includes an optocoupler U2 and a resistor R9. The "3" and "4" terminals of the optocoupler U2 are respectively connected to the feedback control terminal of the PWM control circuit. The "1" terminal of the optocoupler U2 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to an external DC power supply. The "2" terminal of the optocoupler U2 is connected to the output terminal of the operational amplifier circuit.

5. The power supply circuit for a rechargeable battery according to claim 1, characterized in that, The rectifier and filter circuit includes a fuse F1, a thermistor NTC1, a rectifier bridge DP1, and a capacitor E1. One end of the fuse F1 is connected to the live wire of the AC power supply, and the other end of the fuse F1 is connected to terminal "3" of the rectifier bridge DP1. One end of the thermistor NTC1 is connected to the neutral wire of the AC power supply, and the other end of the thermistor NTC1 is connected to terminal "1" of the rectifier bridge DP1. Terminal "2" of the rectifier bridge is grounded. Terminal "4" of the rectifier bridge is connected to one end of capacitor E1 and the input terminal of the transformer circuit, and the other end of capacitor E1 is grounded.

6. The power supply circuit for a rechargeable battery according to claim 1, characterized in that, The transformer circuit includes a primary transformer circuit, a first-stage transformer circuit, a second-stage transformer circuit, and a third-stage transformer circuit. The input terminal of the primary transformer circuit is connected to the output terminal of the rectifier and filter circuit. The output terminal of the primary transformer circuit is connected to the input terminals of the first-stage transformer circuit, the second-stage transformer circuit, and the third-stage transformer circuit, respectively. The output terminal of the first-stage transformer circuit is connected to the input terminal of the PWM control circuit. The output terminals of the second-stage transformer circuit and the third-stage transformer circuit serve as external power outputs.

7. The power supply circuit for a rechargeable battery according to claim 6, characterized in that, The primary transformer circuit includes a transformer T1, a resistor R2, a capacitor C1, and a diode D1. The "3" terminal of the transformer T1 is connected to one end of the resistor R2, one end of the capacitor C1, and the output terminal of the rectifier filter circuit. The other end of the resistor R2 is connected to the other end of the capacitor C1 and the negative terminal of the diode D1. The positive terminal of the diode D1 is connected to the "1" terminal of the transformer T1.

8. The power supply circuit for a rechargeable battery according to claim 7, characterized in that, The secondary transformer circuit includes capacitor C10, resistor R30, diode D7, and capacitor E4. The "12" terminal of transformer T1 is connected to one end of capacitor C10 and the positive terminal of diode D7. The other end of capacitor C10 is connected to one end of resistor R30. The other end of resistor R30 is connected to the negative terminal of diode D7, one end of capacitor E4, and the external output power supply. The "10" terminal of transformer T1 and the other end of capacitor E4 are grounded together.

9. The power supply circuit for a rechargeable battery according to claim 7, characterized in that, The third-stage transformer circuit includes a diode D6, a capacitor E3, and a resistor R24. The "7" terminal of the transformer T1 is connected to the positive terminal of the diode D6, the negative terminal of the diode D6, one end of the capacitor E3, and one end of the resistor R24. The other end of the capacitor E3 is grounded, and the other end of the resistor R24 ​​is connected to the external output power supply. The "9" terminal of the transformer T1 is grounded.

10. The power supply circuit for a rechargeable battery according to claim 1, characterized in that, The PWM control circuit includes resistor R4, capacitors C3, C4, C2, C5, chip U1, resistor R36, diode D2, resistor R1, capacitor E2, resistor R5, resistor R6, NMOS transistor Q1, resistor R7, resistor R8, and capacitor C6. Terminal "1" of chip U1 is connected to one end of capacitor C5 and the feedback control terminal of the feedback voltage circuit; the other end of capacitor C5 is grounded. Terminal "2" of chip U1 is grounded, terminal "5" of chip U1 is grounded, terminal "4" of chip U1 is connected to one end of capacitor C4 and one end of resistor R4; the other end of capacitor C4 is grounded. The other end of resistor R4 is connected to terminal "8" of chip U1 and one end of capacitor C3; the other end of capacitor C3 is grounded. Terminal "4" of chip U1 is connected to... One end of capacitor C2 is connected to one end of resistor R36. The other end of capacitor C2 is grounded. The other end of resistor R36 is connected to one end of capacitor E2, one end of resistor R1, and the negative terminal of diode D2. The other end of capacitor E2 is grounded. The positive terminal of diode D2 is connected to the output terminal of the transformer circuit. The other end of resistor R1 is connected to the output terminal of the rectifier filter circuit. Terminal "6" of chip U1 is connected to one end of resistor R5. The other end of resistor R5 is connected to the gate of NMOS transistor Q1 and one end of resistor R7. Terminal "3" of chip U1 is connected to one end of capacitor C6 and one end of resistor R6. The other end of resistor R6 is connected to one end of resistor R8 and the source of NMOS transistor Q1. The other ends of capacitor C6, resistor R7, and resistor R8 are all grounded. The drain of NMOS transistor Q1 is connected to the input terminal of the transformer circuit.

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