Multi-contact switch synchronism detection circuit

Abstract

The invention provides a multi-contact switch synchronism detection circuit which comprises a rail-to-rail comparator circuit connected with a detected switch, the rail-to-rail comparator circuit is connected with a single-chip microcomputer circuit, and the single-chip microcomputer circuit is connected with a communication circuit; the input end of the direct-current voltage conversion circuit is connected with a power supply, and the output end of the direct-current voltage conversion circuit is respectively connected with the rail-to-rail comparator circuit, the singlechip circuit and the communication circuit; the comparison circuit is directly connected to a detected switch through an interface, a plurality of switches or multi-knife switches can be detected respectively, the device mechanism can transmit a multi-contact synchronization signal to the device mechanism through an RS485 interface, required operation can be carried out on the device mechanism, and the device function is achieved. The module provides synchronism detection for the two multi-contact switches, and the detection efficiency is high.

Description

Technical Field

[0001] The invention relates to a multi-contact switch synchronization detection circuit. Background Art

[0002] A multi-pole switch can also be called a multi-touch switch. Its synchronization refers to the difference between the shortest time and the longest time when the circuit is switched when the switch is driven. In practice, due to the influence of product design, production and processing, the multi-way switch is actually different from the actual waveform. The multi-way switch theory has multiple contacts that are on and off at the same time, which is quite different from the actual waveform. The difficulty in detecting the synchronization of multi-contact switches is that the switch is a mechanical switch, how to accurately distinguish the shortest time and the longest time, the time of the on-off synchronization of the multi-contact switch is ns, how the module captures the ns signal, and processes the signal with the ns time difference, and displays it in the form of multi-contact synchronization.

[0003] The current detection of the synchronization of multi-contact switches is performed using a multi-channel oscilloscope. During the detection, there are many connecting lines and the operation is complicated. The synchronization cannot be read directly, and the oscilloscope needs to be operated manually to indirectly read the synchronization of the multiple contacts, and the detection efficiency is low. For example, a switch opening and closing state monitoring device and monitoring method disclosed in CN107993424A inputs the switch opening and closing state into a signal processing circuit through a switch signal, and the signal processing circuit inputs the switch signal into a single-chip microcomputer after filtering by an inductor and a capacitor, and the switch opening and closing state is judged by the single-chip microcomputer and output through a communication circuit. However, its signal processing circuit can only process a single signal and cannot detect the opening and closing states of multiple switches or multi-pole switches at the same time. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a multi-contact switch synchronization detection circuit.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a multi-contact switch synchronization detection circuit, comprising a rail-to-rail comparator circuit connected to a switch under test, the rail-to-rail comparator circuit connected to a single-chip circuit, and the single-chip circuit connected to a communication circuit; and further comprising a DC voltage conversion circuit, wherein an input end of the DC voltage conversion circuit is connected to a power supply, and an output end is respectively connected to the rail-to-rail comparator circuit, the single-chip circuit, and the communication circuit;

[0007] The rail-to-rail comparator circuit includes 8 rail-to-rail comparator branches, the rail-to-rail comparator is a dual-channel comparator, the switch under test is a 4-pole switch, the 8 rail-to-rail comparator branches are respectively connected to the detection points of the two switches under test, and the output ends are respectively connected to the input ends of the single-chip microcomputer circuit.

[0008] The 8 rail-to-rail comparator branches have the same structure. Any rail-to-rail comparator branch includes a rail-to-rail comparator U5. Pin 1 of the rail-to-rail comparator U5 is connected to one end of resistors R11, R10, and R9 respectively, the other end of resistor R11 is grounded, the other end of resistor R10 is connected to +5V DC, and the other end of resistor R9 is connected to pin 7 of U5; Pin 2 of the rail-to-rail comparator U5 is connected to resistor R14, the other end of resistor R14 is connected to diode D2, resistor R15, and resistor R13 respectively, the other end of diode D2 and resistor R15 is grounded, and the other end of resistor R13 is connected to a detection point of the switch under test; Pin 5 of the rail-to-rail comparator U5 is grounded; Pin 7 of the rail-to-rail comparator U5 is connected to the other end of resistor R12 and resistor R9, and the other end of resistor R12 is connected to the signal input pin of the microcontroller U1; Pin 8 of the rail-to-rail comparator U5 is connected to the +5V DC of the DC voltage conversion circuit. The DC power supply output port is connected to the ground through the capacitor C16 and the capacitor C17 connected in parallel;

[0009] Pin 3 of the rail-to-rail comparator U5 is connected to one end of resistors R18, R16, and R17 respectively, the other end of resistor R18 is grounded, the other end of resistor R16 is connected to a +5V DC power supply, resistor R17 is connected to pin 6 of the rail-to-rail comparator U5 and resistor R15, and the other end of resistor R15 is connected to the signal input pin of the microcontroller U1; pin 4 of the rail-to-rail comparator U5 is connected to resistor R21, the other end of resistor R21 is connected to diode D6, resistor R22, and resistor R20 respectively, the other end of resistor R22 and diode D6 is grounded, and the other end of the resistor R20 is connected to a detection point of the switch under test.

[0010] The rail-to-rail comparator model is TLV3502 4.5ns.

[0011] The detection switch is composed of four normally closed terminals NC1, NC2, NC3, NC4 and four normally open terminals NO1, NO2, NO3, NO4 to form eight detection points, and the eight detection points are respectively connected to the input terminals of four rail-to-rail ratio machine branches.

[0012] The single-chip microcomputer circuit comprises a single-chip microcomputer U1, wherein pin 1 of the single-chip microcomputer U1 is connected to pin 1 of the communication chip U2, pin 2 is grounded, pins 5 and 6 are grounded respectively through a capacitor slot and a capacitor C2, and a crystal oscillator Y1 is also connected between pins 5 and 6; pin 7 of the single-chip microcomputer U1 is connected to a reset power supply; pin 8 of the single-chip microcomputer U1 is grounded, pins 9 and 24 of U1 are connected to a 3V3 power supply and are grounded through two parallel capacitors; pin 22 of the single-chip microcomputer U1 is connected to capacitor C5, and the other end of capacitor C5 is grounded; pin 23 of the single-chip microcomputer U1 is grounded, pins 34 and 37 are used as lead-out ports, pin 35 is grounded, pin 36 is connected to a 3V3 power supply and is grounded through a capacitor C8, pin 44 is grounded through a resistor R1, pin 45 is connected to pin 4 of the communication chip U2, pin 46 is connected to pins 2 and 3 of the communication chip U2 respectively, pin 47 is grounded, and pin 48 is connected to a 3V3 power supply and is grounded through a capacitor C9.

[0013] The model of the single chip microcomputer is HC32F460JEAT.

[0014] The communication circuit includes a communication chip U2, wherein pin 1 and pin 4 of the communication chip U2 are respectively connected to pin 1 and pin 45 of the single-chip computer, and are respectively connected to the cathode of the light-emitting diode RX and the light-emitting diode TX, the anode of the light-emitting diode RX and the light-emitting diode TX are respectively connected to the 5V power supply through the resistor R3 and the resistor R4, pin 5 of the communication chip U2 is grounded, and pin 5 is also respectively connected to the TVS diode D3 and the TVS diode D5, the other end of the TVS diode D3 is connected to pin 6 of the communication chip and the fuse F1, the other end of the TVS diode D5 is connected to pin 7 of the communication chip and the fuse F2, the other end of the fuse F1 and the fuse F2 are used as communication connections, and pin 6 and pin 7 of the chip are also respectively connected to the two ends of the TVS diode D4.

[0015] The communication chip model is TP8485E.

[0016] The DC voltage conversion circuit includes a DC power supply module U3 and a 5V to 3.3V conversion module U4. Pin 1 of the DC power supply module U3 is connected to the negative electrode of the inductor L1 and the diode D10. The other end of the inductor L1 outputs a voltage and current of 5V0.6A and is sequentially connected to one end of the capacitor C15, the positive electrode of the polarity capacitor E1, the negative electrode of the diode D9, one end of the resistor R59, and one end of the resistor R61; Pin 4 of the DC power supply module U3 is connected to the other end of the resistor R59 and the resistor R60. The other end of the resistor R61 is connected to the light-emitting diode PWRRED. The light-emitting diode PWRRED, the other end of the resistor R60, and the other end of the capacitor C15 are connected to the light-emitting diode PWRRED. , the negative electrode of the polarity capacitor E1, the positive electrode of the diode D9, and the positive electrode of the diode D10 are connected to the 5th and 9th pins of the DC power module U3, the 3rd pin of the DC power module U3 is connected to the capacitor C14, the capacitor C14 is connected to the resistor R8, the 6th pin of the DC power module U3 is connected to one end of the resistor R7, the 2nd pin of the DC power module U3 is connected to the resistors R5 and R6 respectively, the 7th pin of the DC power module U3 is connected to the VCC24V power supply, and is connected to the other end of the resistor R5, the capacitor C13, and the negative electrode of the diode D8 in sequence, the positive electrode of D8 and the other end of the capacitor C13, the resistor R6, the resistor R7, and the resistor R8 are connected to the 5th and 9th pins of the DC power module U3.

[0017] The input end of the 3.3V conversion module U4 is connected to a voltage and current of 5V0.6A, and the output end outputs a 3V3 power supply. The input end and the output end are also grounded through capacitors C19 and C20 respectively.

[0018] The beneficial effects of the present invention are as follows: the comparison circuit is directly connected to the switch under test through an interface, and can detect multiple switches or multi-pole switches respectively. The device mechanism can transmit the multi-contact synchronization signal to the upper device mechanism through the RS485 interface, and can perform the required operation on the device mechanism to realize the device function. The module provides synchronization detection of two multi-contact switches with high detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a block diagram of the working principle of the present invention;

[0020] Figure 2 is a circuit diagram of a switch under test of the present invention;

[0021] Figure 3 is a rail-to-rail comparator circuit diagram of the present invention;

[0022] Figure 4 It is the circuit diagram of HC32F460JEAT single chip microcomputer of the present invention;

[0023] Figure 5 is a circuit diagram of a communication circuit of the present invention;

[0024] Figure 6 is a direct current voltage conversion circuit diagram of the present invention;

[0025] Figure 7 It is a 5V to 3.3V conversion circuit diagram of the present invention;

[0026] Figure 8 It is a schematic diagram of the power input port of the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0028] A multi-contact switch synchronization detection circuit includes a rail-to-rail comparator circuit connected to a switch under test, the rail-to-rail comparator circuit is connected to a single-chip circuit, and the single-chip circuit is connected to a communication circuit; and also includes a DC voltage conversion circuit, wherein an input end of the DC voltage conversion circuit is connected to a power supply, and an output end is respectively connected to the rail-to-rail comparator circuit, the single-chip circuit, and the communication circuit;

[0029] The rail-to-rail comparator circuit includes 8 rail-to-rail comparator branches, the rail-to-rail comparator is a dual-channel comparator, the switch under test is a 4-pole switch, the 8 rail-to-rail comparator branches are respectively connected to the detection points of the two switches under test, and the output ends are respectively connected to the input ends of the single-chip microcomputer circuit.

[0030] The 8 rail-to-rail comparator branches have the same structure. Any rail-to-rail comparator branch includes a rail-to-rail comparator U5. Pin 1 of the rail-to-rail comparator U5 is connected to one end of resistors R11, R10, and R9 respectively, the other end of resistor R11 is grounded, the other end of resistor R10 is connected to +5V DC, and the other end of resistor R9 is connected to pin 7 of U5; Pin 2 of the rail-to-rail comparator U5 is connected to resistor R14, the other end of resistor R14 is connected to diode D2, resistor R15, and resistor R13 respectively, the other end of diode D2 and resistor R15 is grounded, and the other end of resistor R13 is connected to a detection point of the switch under test; Pin 5 of the rail-to-rail comparator U5 is grounded; Pin 7 of the rail-to-rail comparator U5 is connected to the other end of resistor R12 and resistor R9, and the other end of resistor R12 is connected to the signal input pin of the microcontroller U1; Pin 8 of the rail-to-rail comparator U5 is connected to the +5V DC of the DC voltage conversion circuit. The DC power supply output port is connected to the ground through the capacitor C16 and the capacitor C17 connected in parallel;

[0031] Pin 3 of the rail-to-rail comparator U5 is connected to one end of resistors R18, R16, and R17 respectively, the other end of resistor R18 is grounded, the other end of resistor R16 is connected to a +5V DC power supply, resistor R17 is connected to pin 6 of the rail-to-rail comparator U5 and resistor R15, and the other end of resistor R15 is connected to the signal input pin of the microcontroller U1; pin 4 of the rail-to-rail comparator U5 is connected to resistor R21, the other end of resistor R21 is connected to diode D6, resistor R22, and resistor R20 respectively, the other end of resistor R22 and diode D6 is grounded, and the other end of the resistor R20 is connected to a detection point of the switch under test.

[0032] The rail-to-rail comparator model is TLV3502 4.5ns.

[0033] The detection switch is composed of four normally closed terminals NC1, NC2, NC3, NC4 and four normally open terminals NO1, NO2, NO3, NO4 to form eight detection points, and the eight detection points are respectively connected to the input terminals of four rail-to-rail ratio machine branches. There are 8 rail-to-rail comparator circuits in total, of which 4 TLV3502 4.5ns rail-to-rail comparator circuits are a group to measure a 4-pole switch under test. 4 of them transmit the normally closed end (NC1, NC2, NC3, NC4) and normally open end (NO1, NO2, NO3, NO4) signals of one switch under test to pins 13, 14, 15, 16, 17, 18, 19, and 20 of U1, and the remaining 4 transmit the normally closed end (NC1, NC2, NC3, NC4) and normally open end (NO1, NO2, NO3, NO4) signals of another switch under test to pins 25, 26, 27, 28, 29, 30, 31, and 21 of U1.

[0034] The single-chip microcomputer circuit comprises a single-chip microcomputer U1, wherein pin 1 of the single-chip microcomputer U1 is connected to pin 1 of the communication chip U2, pin 2 is grounded, pins 5 and 6 are grounded respectively through a capacitor slot and a capacitor C2, and a crystal oscillator Y1 is also connected between pins 5 and 6; pin 7 of the single-chip microcomputer U1 is connected to a reset power supply; pin 8 of the single-chip microcomputer U1 is grounded, pins 9 and 24 of U1 are connected to a 3V3 power supply and are grounded through two parallel capacitors; pin 22 of the single-chip microcomputer U1 is connected to capacitor C5, and the other end of capacitor C5 is grounded; pin 23 of the single-chip microcomputer U1 is grounded, pins 34 and 37 are used as lead-out ports, pin 35 is grounded, pin 36 is connected to a 3V3 power supply and is grounded through a capacitor C8, pin 44 is grounded through a resistor R1, pin 45 is connected to pin 4 of the communication chip U2, pin 46 is connected to pins 2 and 3 of the communication chip U2 respectively, pin 47 is grounded, and pin 48 is connected to a 3V3 power supply and is grounded through a capacitor C9.

[0035] The model of the single chip microcomputer is HC32F460JEAT.

[0036] The communication circuit includes a communication chip U2, wherein pin 1 and pin 4 of the communication chip U2 are respectively connected to pin 1 and pin 45 of the single-chip computer, and are respectively connected to the cathode of the light-emitting diode RX and the light-emitting diode TX, the anode of the light-emitting diode RX and the light-emitting diode TX are respectively connected to the 5V power supply through the resistor R3 and the resistor R4, pin 5 of the communication chip U2 is grounded, and pin 5 is also respectively connected to the TVS diode D3 and the TVS diode D5, the other end of the TVS diode D3 is connected to pin 6 of the communication chip and the fuse F1, the other end of the TVS diode D5 is connected to pin 7 of the communication chip and the fuse F2, the other end of the fuse F1 and the fuse F2 are used as communication connections, and pin 6 and pin 7 of the chip are also respectively connected to the two ends of the TVS diode D4.

[0037] The communication chip model is TP8485E.

[0038] The DC voltage conversion circuit includes a DC power supply module U3 and a 5V to 3.3V conversion module U4. Pin 1 of the DC power supply module U3 is connected to the negative electrode of the inductor L1 and the diode D10. The other end of the inductor L1 outputs a voltage and current of 5V0.6A and is sequentially connected to one end of the capacitor C15, the positive electrode of the polarity capacitor E1, the negative electrode of the diode D9, one end of the resistor R59, and one end of the resistor R61; Pin 4 of the DC power supply module U3 is connected to the other end of the resistor R59 and the resistor R60. The other end of the resistor R61 is connected to the light-emitting diode PWRRED. The light-emitting diode PWRRED, the other end of the resistor R60, and the other end of the capacitor C15 are connected to the light-emitting diode PWRRED. , the negative electrode of the polarity capacitor E1, the positive electrode of the diode D9, and the positive electrode of the diode D10 are connected to the 5 and 9 pins of the DC power module U3, the 3 pin of the DC power module U3 is connected to the capacitor C14, the capacitor C14 is connected to the resistor R8, the 6 pin of the DC power module U3 is connected to one end of the resistor R7, the 2 pin of the DC power module U3 is connected to the resistors R5 and R6 respectively, the 7 pin of the DC power module U3 is connected to the VCC24V power supply, and is sequentially connected to the other end of the resistor R5, the capacitor C13, the negative electrode of the diode D8, the positive electrode of D8 and the other end of the capacitor C13, the resistor R6, the resistor R7, and the resistor R8 are connected to the 5 and 9 pins of the DC power module U3. The input end of the 3.3V conversion module U4 is connected to the voltage and current of 5V0.6A, and the output end outputs a 3V3 power supply, and the input end and the output end are also grounded through the capacitor C19 and the capacitor C20 respectively.

Claims

1. A multi-contact switch synchronization detection circuit, characterized in that: It includes a rail-to-rail comparator circuit connected to the switch under test, the rail-to-rail comparator circuit is connected to the single-chip circuit, and the single-chip circuit is connected to the communication circuit; it also includes a DC voltage conversion circuit, the input end of the DC voltage conversion circuit is connected to the power supply, and the output end is respectively connected to the rail-to-rail comparator circuit, the single-chip circuit, and the communication circuit; The rail-to-rail comparator circuit includes 8 rail-to-rail comparator branches, the rail-to-rail comparator is a dual-channel comparator, the switch under test is a 4-pole switch, the 8 rail-to-rail comparator branches are respectively connected to the detection points of the two switches under test, and the output ends are respectively connected to the input ends of the single-chip microcomputer circuit.

2. The multi-contact switch synchronization detection circuit according to claim 1, characterized in that: The 8 rail-to-rail comparator branches have the same structure. Any rail-to-rail comparator branch includes a rail-to-rail comparator U5. Pin 1 of the rail-to-rail comparator U5 is connected to one end of resistors R11, R10, and R9 respectively, the other end of resistor R11 is grounded, the other end of resistor R10 is connected to +5V DC, and the other end of resistor R9 is connected to pin 7 of U5; Pin 2 of the rail-to-rail comparator U5 is connected to resistor R14, the other end of resistor R14 is connected to diode D2, resistor R15, and resistor R13 respectively, the other end of diode D2 and resistor R15 is grounded, and the other end of resistor R13 is connected to a detection point of the switch under test; Pin 5 of the rail-to-rail comparator U5 is grounded; Pin 7 of the rail-to-rail comparator U5 is connected to the other end of resistor R12 and resistor R9, and the other end of resistor R12 is connected to the signal input pin of the microcontroller U1; Pin 8 of the rail-to-rail comparator U5 is connected to the +5V DC of the DC voltage conversion circuit. The DC power supply output port is connected to the ground through the capacitor C16 and the capacitor C17 connected in parallel; Pin 3 of the rail-to-rail comparator U5 is connected to one end of resistors R18, R16, and R17 respectively, the other end of resistor R18 is grounded, the other end of resistor R16 is connected to a +5V DC power supply, resistor R17 is connected to pin 6 of the rail-to-rail comparator U5 and resistor R15, and the other end of resistor R15 is connected to the signal input pin of the microcontroller U1; pin 4 of the rail-to-rail comparator U5 is connected to resistor R21, the other end of resistor R21 is connected to diode D6, resistor R22, and resistor R20 respectively, the other end of resistor R22 and diode D6 is grounded, and the other end of the resistor R20 is connected to a detection point of the switch under test.

3. The multi-contact switch synchronization detection circuit according to claim 1, characterized in that: The rail-to-rail comparator model is TLV3502 4.5ns.

4. The multi-contact switch synchronization detection circuit according to claim 1, characterized in that: The detection switch is composed of four normally closed terminals NC1, NC2, NC3, NC4 and four normally open terminals NO1, NO2, NO3, NO4 to form eight detection points, and the eight detection points are respectively connected to the input terminals of four rail-to-rail ratio machine branches.

5. The multi-contact switch synchronization detection circuit according to claim 1, characterized in that: The single-chip microcomputer circuit single-chip microcomputer U1, pin 1 of the single-chip microcomputer U1 is connected to pin 1 of the communication chip U2, pin 2 is grounded, pins 5 and 6 are grounded through a capacitor slot and capacitor C2 respectively, and a crystal oscillator Y1 is also connected between pins 5 and 6; Pin 7 of the microcontroller U1 is connected to the reset power supply; Pin 8 of the microcontroller U1 is grounded, Pin 9 and Pin 24 of U1 are connected to the 3V3 power supply and grounded through two parallel capacitors; Pin 22 of the microcontroller U1 is connected to capacitor C5, and the other end of capacitor C5 is grounded; Pin 23 of the microcontroller U1 is grounded, pins 34 and 37 are used as lead-out ports, pin 35 is grounded, pin 36 is connected to a 3V3 power supply and grounded through capacitor C8, pin 44 is grounded through resistor R1, pin 45 is connected to pin 4 of the communication chip U2, pin 46 is connected to pins 2 and 3 of the communication chip U2 respectively, pin 47 is grounded, and pin 48 is connected to a 3V3 power supply and grounded through capacitor C9.

6. The multi-contact switch synchronization detection circuit according to claim 5, characterized in that: The model of the single chip microcomputer is HC32F460JEAT.

7. The multi-contact switch synchronization detection circuit according to claim 1, characterized in that: The communication circuit includes a communication chip U2, wherein pin 1 and pin 4 of the communication chip U2 are respectively connected to pin 1 and pin 45 of the single-chip computer, and are respectively connected to the cathode of the light-emitting diode RX and the light-emitting diode TX, the anode of the light-emitting diode RX and the light-emitting diode TX are respectively connected to the 5V power supply through the resistor R3 and the resistor R4, pin 5 of the communication chip U2 is grounded, and pin 5 is also respectively connected to the TVS diode D3 and the TVS diode D5, the other end of the TVS diode D3 is connected to pin 6 of the communication chip and the fuse F1, the other end of the TVS diode D5 is connected to pin 7 of the communication chip and the fuse F2, the other end of the fuse F1 and the fuse F2 are used as communication connections, and pin 6 and pin 7 of the chip are also respectively connected to the two ends of the TVS diode D4.

8. The multi-contact switch synchronization detection circuit according to claim 7, characterized in that: The communication chip model is TP8485E.

9. The multi-contact switch synchronization detection circuit according to claim 1, characterized in that: The DC voltage conversion circuit includes a DC power supply module U3 and a 5V to 3.3V conversion module U4. Pin 1 of the DC power supply module U3 is connected to the negative electrode of the inductor L1 and the diode D10. The other end of the inductor L1 outputs a voltage and current of 5V0.6A and is sequentially connected to one end of the capacitor C15, the positive electrode of the polarity capacitor E1, the negative electrode of the diode D9, one end of the resistor R59, and one end of the resistor R61; Pin 4 of the DC power supply module U3 is connected to the other end of the resistor R59 and the resistor R60. The other end of the resistor R61 is connected to the light-emitting diode PWRRED. The light-emitting diode PWRRED, the other end of the resistor R60, and the other end of the capacitor C15 are connected to the light-emitting diode PWRRED. , the negative electrode of the polarity capacitor E1, the positive electrode of the diode D9, and the positive electrode of the diode D10 are connected to the 5th and 9th pins of the DC power module U3, the 3rd pin of the DC power module U3 is connected to the capacitor C14, the capacitor C14 is connected to the resistor R8, the 6th pin of the DC power module U3 is connected to one end of the resistor R7, the 2nd pin of the DC power module U3 is connected to the resistors R5 and R6 respectively, the 7th pin of the DC power module U3 is connected to the VCC24V power supply, and is connected to the other end of the resistor R5, the capacitor C13, and the negative electrode of the diode D8 in sequence, the positive electrode of D8 and the other end of the capacitor C13, the resistor R6, the resistor R7, and the resistor R8 are connected to the 5th and 9th pins of the DC power module U3.

10. The multi-contact switch synchronization detection circuit according to claim 1, characterized in that: The input end of the 3.3V conversion module U4 is connected to a voltage and current of 5V0.6A, and the output end outputs a 3V3 power supply. The input end and the output end are also grounded through capacitors C19 and C20 respectively.

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