An electronic switch circuit for an electric motorcycle

Abstract

This invention discloses an electronic switch circuit for electric motorcycles, relating to the field of electronic switch technology. The invention includes a power supply step-down circuit, a one-button start / stop circuit, a drive circuit, a power switch circuit, and a system protection circuit. The power supply step-down circuit adapts to a wide voltage input, has extremely low operating current, and can be connected in parallel to a controlled power supply. The one-button start / stop circuit features an ultra-low power consumption design, enabling jogging one-button start / stop functionality. The drive circuit accelerates the rise and fall times of the switching transistor. The power switch circuit is a bidirectional switch design, indistinguishable between positive and negative, high and low ends, and can directly replace a DC circuit breaker. The system protection circuit includes dual protection against short circuits and overcurrent, and provides bidirectional protection. This invention features extremely low standby and operating power consumption, complete sealing and electrical protection, and can completely replace an air switch, making it usable in any DC device.

Description

Technical Field

[0001] This invention relates to the field of electronic switch technology, and in particular to an electronic switch circuit for an electric motorcycle. Background Technology

[0002] Electric motorcycles use batteries to drive motors. The electric drive and control system consists of a drive motor, power supply, and motor speed control device. The electric drive and control system is the core of an electric vehicle and the biggest difference from vehicles driven by internal combustion engines. An electronic switch is an operating unit that uses electronic circuits and power electronic devices to realize the opening and closing of circuits. It includes at least one controllable electronic drive device. In the starting and control of electric motorcycles, electronic switches are gradually replacing air switches.

[0003] Currently, the power consumption control effect of electronic switches in electric motorcycles is not good, and the sealing and electrical protection effects of their operating circuits need to be improved, which has certain limitations. Therefore, we propose an electronic switch circuit for electric motorcycles. Summary of the Invention

[0004] The purpose of this invention is to provide an electronic switching circuit for electric motorcycles, thereby solving the problems mentioned in the background.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0006] This invention relates to an electronic switching circuit for an electric motorcycle, comprising a power supply step-down circuit, a one-button start / stop circuit, a drive circuit, a power switch circuit, and a system protection circuit. The power supply step-down circuit is adaptable to a wide voltage input, has extremely low operating current, and can be connected in parallel to a controlled power supply. The one-button start / stop circuit features an ultra-low power consumption design, enabling jogging one-button start / stop functionality. The drive circuit is used to accelerate the rise and fall time of the switching transistor. The power switch circuit is a bidirectional switch design, indistinguishable between positive and negative, high-side and low-side, and can directly replace a DC circuit breaker. The system protection circuit includes dual protection against short circuits and overcurrent, and has bidirectional protection.

[0007] The power supply step-down circuit includes two sets of transformer coils (model 18T). One pin 2 of the 18T inductor coil is grounded, and the other pin 3 is connected to resistors R11 and R13 respectively. One end of R11 is connected to diode D5, and one end of D5 is grounded through capacitor C6. The other end of D5 is connected in parallel with the positive terminal of diode D4. D4 includes three sets of series circuits. In the first set of series circuits, the signal is grounded through Zener diode DZ2. In the second set of series circuits, the signal is grounded through capacitor C7. In the third set of series circuits, resistor R6 is connected. One end of R6 is connected to the positive terminal circuit of the control power supply, which is introduced from diode D2 and includes six sets of series circuits. In one set of circuits, the signal is grounded through CE1. One set is connected to R6. One set is connected to resistor R4. One set is connected to capacitor C1. One end of R4 is connected to resistor R9. R9 and C1 form a parallel connection. One end of R9 is connected to diode D3. One end of D3 is connected to... The transformer coil 18T has pin 3 connected in parallel. One end of D3 is also connected to pin 1 and pin 6. DR1 is connected in series in the parallel circuit of pin 6. One end of DR1 is connected back to D3. One end of resistor R13 is connected in parallel with resistor R17. R17 is connected to two sets of resistors R18. The signal of R18 is grounded. One end of R17 is connected in parallel to the control terminal through pin 8. The control terminal includes five sets of parallel circuits: one set is grounded by pin 1; one set is grounded by pin 2 connected to resistors R33 and R36; one set is a parallel circuit of diode D3 connected by pin 4; one set is grounded by pin 7 connected to capacitor C12 and parallel with resistor R34; one set is grounded by pin 6 connected to capacitor C11; and it is connected in series with a one-button start / stop circuit. Another set of circuits has pins 4 and 5 connected in series at both ends of the inductor coil 18T. One end of pin 5 is connected to diode D1. Its series circuit is grounded through resistor R8, capacitors C2 and C3, and resistor R5. This circuit is connected in series with the drive circuit.

[0008] The one-button start / stop circuit includes resistors R31 and R32. One end of R31 is connected in parallel with the positive input terminal of the power supply step-down circuit, and the other end of R31 is connected to the system protection circuit via a control switch. One end of R32 is connected in parallel with one end of resistor R28. R28 is connected to the one-button start / stop circuit through transistor Q3. Resistor R26 is connected in the series circuit of R28. R26 is grounded through transistor Q4. The other end of R32 is grounded through resistor R37 and capacitor C15 respectively.

[0009] The driving circuit includes three-terminal regulators IC1 and IC2. One end of IC1 is connected in series with resistor R7 and capacitor C5. One end of IC2 is connected to resistor R3. One end of R3 is connected to the power supply step-down circuit through transistor Q1. The other end of R3 is connected to the power switch circuit through resistor R1. The parallel circuit of the collector of Q1 is also connected in series with resistor R2. The series circuit of one end of R2 is connected in parallel with resistor R10 and capacitor C4, and is connected in parallel with the output terminal of the power supply step-down circuit and the input terminal of the power switch circuit, respectively.

[0010] The power switch circuit includes a resistor R23. The positive terminal of R23 is connected to a transistor Q2 and a resistor R14. Q2 is connected to the controlled input / output terminal of the circuit. One end of the resistor R14 is connected to a resistor R12, which is connected to the drive circuit. The negative terminal of R23 is connected to a transistor Q5 and a resistor R30. Q5 is connected to the controlled output terminal of the circuit. One end of the resistor R30 is connected to a resistor R35, which is connected in parallel with R12.

[0011] The system protection circuit includes two sets of integrated short-circuit and overcurrent protection circuits (each set includes a current amplification module and a short-circuit and overcurrent protection module). One end of the short-circuit protection circuit is connected to resistor R38 via diode D8. R38 is connected in series and grounded via capacitor C14. An overcurrent protection circuit is connected in parallel with R38. The anode of the short-circuit protection circuit is connected to the power supply via pin 3 and grounded via parallel resistor R39. The cathode of the short-circuit protection circuit is connected to resistors R43 and R44 and capacitor C16 via pin 2. One end of R43 is connected to 12V. The voltage is connected to R44 and C16. The anode of the short-circuit protection circuit is also connected to the ground via capacitor C13. At this time, the cathode of the short-circuit protection circuit is directly grounded. The overcurrent protection circuit is connected to diode D9 via pin 7. In the parallel circuit of D9, it is connected to the short-circuit protection circuit via resistor R40. The anode of the overcurrent protection circuit is connected to the power supply via pin 5. Its cathode is connected to resistors R41, R42 and capacitor C17 respectively. Resistor R41 is connected to 12V voltage. R42 and C17 are grounded respectively. The short-circuit protection circuit and the overcurrent protection circuit are connected in parallel and then connected to the control switch.

[0012] Another set of short-circuit protection circuits is connected to the power supply via diode D6 and resistor R19 in parallel at pin 7. The power supply is grounded via capacitor C9 in the parallel circuit. The anode of the short-circuit protection circuit is connected to resistors R15 and R21 via pin 5, with R15 grounded and R21 connected to the positive signal terminal. The cathode of the short-circuit protection circuit is connected to resistors R24 and R27 via pin 6, with R24 connected to the negative signal terminal and one end of R27 connected to the parallel circuit of D6. The other set of overcurrent protection circuits is connected to a diode in parallel at pin 1. D7 and resistor R20, one end of R20 is connected to the power supply and grounded through capacitor C10. The anode of the overcurrent protection circuit is connected in series with resistors R16 and R22 through pin 3. One end of R16 is grounded and R22 is connected to the negative terminal of the signal. The cathode of the overcurrent protection circuit is connected in series with resistors R25 and R29 through pin 2. R25 is connected to the positive terminal of the signal and R29 is connected to the parallel circuit of diode D7. The anode of the overcurrent protection circuit is also grounded through capacitor C8. One end of C8 is connected to a 12V voltage. At this time, the cathode of the overcurrent protection circuit is grounded.

[0013] The present invention has the following beneficial effects:

[0014] The present invention relates to an electronic switch circuit for electric motorcycles, which has extremely low standby and operating power consumption, and complete sealing and electrical protection. It can completely replace air switches and can be used in any DC device, such as electric bicycles, motorcycles, or household backup power supplies.

[0015] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the electronic switch circuit control for the electric motorcycle of the present invention;

[0018] Figure 2 This is a schematic diagram of the power supply step-down circuit control for the electronic switch circuit of the electric motorcycle of the present invention;

[0019] Figure 3 This is a schematic diagram of the one-button start / stop circuit control for the electronic switch circuit of the electric motorcycle of the present invention.

[0020] Figure 4 This is a schematic diagram of the drive circuit control of the electronic switch circuit for the electric motorcycle of the present invention.

[0021] Figure 5 This is a schematic diagram of the power switch circuit control for the electronic switch circuit of the electric motorcycle of the present invention;

[0022] Figure 6 This is a schematic diagram of the protection circuit control of the electronic switch circuit system for electric motorcycles according to the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1 As shown: This invention relates to an electronic switching circuit for an electric motorcycle, comprising a power supply step-down circuit, a one-button start / stop circuit, a drive circuit, a power switch circuit, and a system protection circuit. The power supply step-down circuit can adapt to a wide voltage input, has extremely low operating current, and can be connected in parallel to a controlled power supply, reducing the need for an external power supply and wiring complexity. The one-button start / stop circuit features an ultra-low power consumption design in standby mode, enabling inching one-button start / stop functionality and increasing system reliability. The drive circuit accelerates the rise and fall time of the switching transistor, ensuring that the switching transistor is not damaged by the variable resistance region. The power switch circuit is a bidirectional switch design, regardless of positive or negative, high or low end, and can directly replace a DC circuit breaker, making it simple and easy to operate. The system protection circuit has dual protection against short circuits and overcurrents, and also provides bidirectional protection.

[0025] like Figure 2As shown, the power supply step-down circuit includes two sets of transformer coils (model 18T). One end of the 18T inductor coil is grounded at pin 2, and the other end of the 18T coil is connected to resistors R11 and R13 at pin 3. One end of R11 is connected to diode D5, and one end of D5 is grounded through capacitor C6. The other end of D5 is connected in parallel with the positive terminal of diode D4. D4 includes three sets of series circuits. In the first set of series circuits, the signal is grounded through Zener diode DZ2. In the second set of series circuits, the signal is grounded through capacitor C7. In the third set of series circuits, resistor R6 is connected. One end of R6 is connected to the positive terminal circuit of the control power supply, which is introduced from diode D2. This includes six sets of series circuits. In one set of circuits, the signal is grounded through CE1. One set is connected to R6. One set is connected to resistor R4. One set is connected to capacitor C1. One end of R4 is connected to resistor R9. R9 and C1 form a parallel connection. One end of R9 is connected to diode D3. One end of D3 is connected to the transformer. Pin 3 of the inductor coil 18T is connected in parallel. One end of D3 is also connected to pin 1 and pin 6. DR1 is connected in series in the parallel circuit of pin 6. One end of DR1 is connected back to D3. One end of resistor R13 is connected in parallel with resistor R17. R17 is connected to two sets of resistors R18. The signal of R18 is grounded. One end of R17 is connected in parallel to the control terminal through pin 8. The control terminal also includes 5 sets of parallel circuits. One set is grounded by the signal of pin 1. One set is grounded by the signal of pin 2 after connecting resistors R33 and R36. One set is connected in parallel by pin 4 to the parallel circuit of diode D3. One set is connected in parallel by pin 7 to capacitor C12 and resistor R34 after connecting in parallel to the signal of pin 7. One set is grounded by pin 6 to capacitor C11. It is also connected in series with a one-button start / stop circuit. The other set of inductor coil 18T is connected in series by pins 4 and 5 respectively. One end of pin 5 is connected to diode D1. Its series circuit is grounded through resistor R8, capacitor C2, C3 and resistor R5 respectively. This circuit is connected in series with the drive circuit.

[0026] like Figure 3 As shown, the one-button start / stop circuit includes resistors R31 and R32. One end of R31 is connected in parallel with the positive input terminal of the power supply step-down circuit, and the other end of R31 is connected to the system protection circuit via a control switch. One end of R32 is connected in parallel with one end of resistor R28. R28 is connected to the one-button start / stop circuit through transistor Q3. Resistor R26 is connected in the series circuit of R28. R26 is grounded through transistor Q4. The other end of R32 is grounded through resistor R37 and capacitor C15 respectively.

[0027] like Figure 4As shown, the driving circuit includes three-terminal regulators IC1 and IC2. One end of IC1 is connected in series with resistor R7 and capacitor C5. One end of IC2 is connected to resistor R3. One end of R3 is connected to the power supply step-down circuit through transistor Q1. The other end of R3 is connected to the power switch circuit through resistor R1. In the parallel circuit of the collector of Q1, resistor R2 is also connected in series. In the series circuit of one end of R2, resistor R10 and capacitor C4 are connected in parallel with the output terminal of the power supply step-down circuit and the input terminal of the power switch circuit, respectively.

[0028] like Figure 5 As shown, the power switch circuit includes resistor R23. The positive terminal of R23 is connected to transistor Q2 and resistor R14. Q2 is connected to the controlled input and output terminals of the circuit. One end of resistor R14 is connected to resistor R12, which is connected to the drive circuit. The negative terminal of R23 is connected to transistor Q5 and resistor R30. Q5 is connected to the controlled output terminal of the circuit. One end of R30 is connected to resistor R35, which is connected in parallel with R12.

[0029] like Figure 6As shown, the system protection circuit includes two sets of integrated short-circuit and overcurrent protection circuits (each set includes a current amplification module and a short-circuit and overcurrent protection module). One end of the short-circuit protection circuit is connected to resistor R38 via diode D8. R38 is connected in series and grounded via capacitor C14. An overcurrent protection circuit is connected in parallel with R38. The anode of the short-circuit protection circuit is connected to the power supply via pin 3 and grounded via parallel resistor R39. The cathode of the short-circuit protection circuit is connected to resistors R43 and R44 and capacitor C16 via pin 2. One end of the circuit is connected to 12V, R44 is grounded, C16 is grounded, and the anode of the short-circuit protection circuit is also connected to capacitor C13 grounded. At this time, the cathode of the short-circuit protection circuit is directly grounded. The overcurrent protection circuit is connected to diode D9 through pin 7. In the parallel circuit of D9, it is connected to the short-circuit protection circuit via resistor R40. The anode of the overcurrent protection circuit is connected to the power supply through pin 5, and its cathode is connected to resistors R41 and R42 and capacitor C17 respectively. Resistor R41 is connected to 12V, and R42 and C17 are grounded respectively. The short-circuit protection circuit and the overcurrent protection circuit... One set of overcurrent protection circuits is connected in parallel to the control switch; another set of short-circuit protection circuits is connected to the power supply via diode D6 and resistor R19 in parallel through pin 7. The power supply is grounded via capacitor C9 in the parallel circuit. The anode of the short-circuit protection circuit is connected to resistors R15 and R21 via pin 5, with R15 grounded and R21 connected to the positive signal terminal. The cathode of the short-circuit protection circuit is connected to resistors R24 and R27 via pin 6, with R24 connected to the negative signal terminal. One end of R27 is connected to the parallel circuit of D6. Another set of overcurrent protection circuits is connected via pin... 1. A diode D7 and a resistor R20 are connected in parallel. One end of R20 is connected to the power supply and grounded through a capacitor C10. The anode of the overcurrent protection circuit is connected in series with resistors R16 and R22 through pin 3. One end of R16 is grounded, and R22 is connected to the negative terminal of the signal. The cathode of the overcurrent protection circuit is connected in series with resistors R25 and R29 through pin 2. R25 is connected to the positive terminal of the signal, and R29 is connected to the parallel circuit of diode D7. The anode of the overcurrent protection circuit is also grounded through capacitor C8. One end of C8 is connected to a 12V voltage. At this time, the cathode of the overcurrent protection circuit is grounded.

[0030] This solution controls the power supply through R6, which powers the power chip via a one-button start / stop circuit to start the power supply step-down circuit. The stepped-down output is rectified and then used to power the power switch circuit via a drive circuit, causing the power switch circuit to open or close. The system protection circuit is also powered by this circuit. The system protection circuit consists of two current amplifiers (bidirectional) and short-circuit overcurrent protection, which are controlled by U1 to power the one-button start / stop circuit.

[0031] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An electronic switch circuit for an electric motorcycle, characterized in that, The system includes a power supply step-down circuit, a one-button start / stop circuit, a drive circuit, a power switch circuit, and a system protection circuit. The power supply step-down circuit is connected in parallel to the controlled power supply. The output of the power supply step-down circuit is connected in parallel to the drive circuit. The output of the drive circuit is connected to the control terminal of the power switch circuit. The system protection circuit is connected to the power switch circuit. The power switch circuit is a bidirectional switch design. The power supply step-down circuit includes a transformer 18T and a power chip IC3. One end of the auxiliary coil of the transformer 18T is grounded. The other end of the auxiliary coil of the transformer 18T is connected to one end of resistors R11 and R13 respectively. The other end of resistor R11 is connected to the anode of diode D5. The cathode of diode D5 is grounded via capacitor C6. The cathode of diode D5 is also connected to the anode of diode D4. The cathode of diode D4 is grounded via a parallel branch consisting of a Zener diode DZ2 and capacitor C7. The cathode of diode D4 is also connected to the one-button start / stop circuit. The other end of resistor R13 is connected via a parallel branch consisting of resistors R17 and R18. The circuit signal is grounded. The common connection point of resistors R13 and R17 is connected to pin 8 of power chip IC3. Pin 4 of power chip IC3 is connected to one end of the primary coil of transformer 18T. The other end of the primary coil of transformer 18T is connected to the anode of diode D3. The cathode of diode D3 is connected to the other end of the primary coil of transformer 18T via resistor R9 and capacitor C1. Resistor R4 is connected in parallel with capacitor C1. The cathode of Zener diode DR1 is connected to the cathode of diode D3. The anode of Zener diode DR1 is connected to the other end of the primary coil of transformer 18T. The positive terminal of the controlled power supply is introduced through diode D2 and connected to the other end of the primary coil of transformer 18T. The power supply pin 6 of power chip IC3 is connected to the negative terminal of the controlled power supply via a one-button start / stop circuit. Pin 7 of power chip IC3 is grounded via capacitor C12 and resistor R34. Pin 2 of power chip IC3 is grounded via a parallel branch composed of resistors R33 and R36. The secondary coil of transformer 18T is connected in parallel with a drive circuit. The one-button start / stop circuit includes transistors Q3, Q4, and Q6, and a control switch. The drain of transistor Q3 is connected to pin 6 of the power supply chip IC3, and the source of transistor Q3 is connected to the cathode of diode D4. The source of transistor Q3 is also connected to one end of resistors R26 and R28. The other end of resistor R26 is connected to the gate of transistor Q3 and the drain of transistor Q4. The other end of resistor R28 is connected to the gate of transistor Q4 via resistor R32. The end of resistor R32 furthest from the gate of transistor Q4 is grounded via resistor R37 and capacitor C15. Resistor R28... The other end is also connected to the drain of transistor Q6. The source of transistor Q6 is connected to the negative terminal of the controlled power supply. The gate of transistor Q6 is connected to the gate of transistor Q3 via resistor R31. The gate of transistor Q6 is also connected to one end of the control switch. The other end of the control switch is connected to the common connection point of resistor R37 and capacitor C15. One end of the control switch is also connected to pin 3 of optocoupler chip U1 via resistor R45. The other end of the control switch is also connected to pin 4 of optocoupler chip U1 via diode D10. Pin 2 of optocoupler chip U1 is grounded. Pin 1 of optocoupler chip U1 is connected to the system protection circuit. The power supply chip IC3 is powered by a one-button start / stop circuit to start the power supply step-down circuit. The power supply step-down circuit controls the power switch circuit to open or close via a drive circuit. The system protection circuit controls the one-button start / stop circuit via an optocoupler chip U1.

2. The electronic switch circuit for an electric motorcycle according to claim 1, characterized in that, The driving circuit includes transistor Q1, voltage regulator chips IC1 and IC2. The source of transistor Q1 is connected to one end of the secondary coil of transformer 18T via diode D1. The other end of the secondary coil of transformer 18T is grounded. A parallel branch consisting of resistor R2, resistor R10, and capacitor C4 is connected in series and then connected to the two ends of the secondary coil of transformer 18T. The drain of transistor Q1 is connected to the first end of voltage regulator chip IC1 via resistor R1. The gate of transistor Q1 is connected to the first end of voltage regulator chip IC2. Resistor R3 is connected between the gate and source of transistor Q1. The second end of voltage regulator chip IC2 is connected to the common connection point of resistors R2 and R10. The third ends of voltage regulator chips IC2 and IC1 are both grounded. The gate of transistor Q1 is connected to the second end of voltage regulator chip IC1 via resistor R7. The two ends of capacitor C5 are connected to the second end of voltage regulator chip IC1 and ground, respectively. The first and third ends of voltage regulator chip IC1 serve as the output terminals of the driving circuit and are connected to the control terminals of the power switch circuit.

3. The electronic switch circuit for an electric motorcycle according to claim 2, characterized in that, The cathode of diode D1 is connected to ground via resistor R8. Capacitors C2 and C3 are both connected in parallel with resistor R8. The cathode of Zener diode DZ1 is connected to the cathode of diode D1, and the anode of Zener diode DZ1 is grounded. One end of resistor R5 is connected to the cathode of diode D1, and the other end of resistor R5 is grounded via LED1.

4. The electronic switch circuit for an electric motorcycle according to claim 2, characterized in that, The power switching circuit includes transistors Q2 and Q5, and resistor R23. One end of resistor R23 is connected to the source of transistor Q2 and one end of resistor R14. The drain of transistor Q2 is connected to the first controlled input / output terminal of the circuit. The other end of resistor R14 is connected to one end of resistor R12 and the gate of transistor Q2. The other end of resistor R12 is connected to the first terminal of voltage regulator chip IC1. The other end of resistor R23 is connected to the source of transistor Q5 and one end of resistor R30. The drain of transistor Q5 is connected to the second controlled input / output terminal of the circuit. The other end of resistor R30 is connected to one end of resistor R35 and the gate of transistor Q5. The other end of resistor R35 is connected to the first terminal of voltage regulator chip IC1. The other end of resistor R23 is also connected to the third terminal of voltage regulator chip IC1.

5. The electronic switch circuit for an electric motorcycle according to claim 4, characterized in that, The system protection circuit includes a short-circuit protection circuit and an overcurrent protection circuit. The short-circuit protection circuit includes chips U0A and U2A. The positive and negative input terminals of chip U0A are connected to the two ends of resistor R23, respectively. The positive input terminal of chip U0A is also grounded via resistor R16. The negative input terminal of chip U0A is connected to its output terminal via resistor R29. The output terminal of chip U0A is connected to the positive input terminal of chip U2A via diode D7 and resistor R20. The positive input terminal of chip U2A is also grounded via resistor R39. The negative input terminal of chip U2A is connected to a +12V power supply via resistor R43. The end of resistor R43 furthest from the +12V power supply is grounded via resistor R44 and capacitor C16. The output terminal of chip U2A is connected to… Connect pin 1 of optocoupler chip U1. The end of resistor R38 furthest from diode D8 is grounded via capacitor C14. An overcurrent protection circuit includes chip U0B and chip U2B. The positive and negative input terminals of chip U0B are connected to the two ends of resistor R23 respectively. The positive input terminal of chip U0B is also grounded via resistor R15. The negative input terminal of chip U0B is connected to the output terminal of chip U0B via resistor R27. The output terminal of chip U0B is connected to the positive input terminal of chip U2B via diode D6 and resistor R19. The negative input terminal of chip U2B is connected to the +12V power supply via resistor R41. The end of resistor R41 furthest from +12V is grounded via resistor R42 and capacitor C17 respectively. The output terminal of chip U2B is connected to pin 1 of optocoupler chip U1 via diode D9 and resistor R40.

Images