Voltage monitoring control circuit

Abstract

The utility model relates to the technical field of switch power supply voltage monitoring, in particular to a voltage monitoring control circuit, which comprises a power supply input circuit, a voltage monitoring circuit and an MCU (Microprogrammed Control Unit) control circuit, the power supply input circuit comprises a power supply input end JE1 and a triode Q6; the number of the voltage monitoring circuits is multiple, and the voltage monitoring threshold values of the voltage monitoring circuits are different. Each voltage monitoring circuit comprises a monitoring diode and a conduction switch piece, the output end of the power supply input circuit is connected with the MCU control circuit after passing through the voltage monitoring circuit, and the conduction switch piece is connected with the MCU control circuit. According to the utility model, the working stability and reliability are improved, when the voltage is too high or too low, the power supply path of the power supply input circuit can be directly cut off, the effects of overvoltage protection and undervoltage protection are achieved, and the back-end circuit of the switch can be well protected without depending on the power supply.

Description

Technical Field

[0001] The utility model relates to the technical field of switch power supply voltage monitoring, in particular to a voltage monitoring control circuit. Background Art

[0002] Nowadays, there are many types of switches on the market. Basically, the input power of switches is a low-voltage DC input power supply, among which 12V DC power supply is the most common, and other types of DC power supply account for a smaller proportion. However, these DC power supplies often either lack overvoltage protection and undervoltage protection, or the overvoltage protection voltage is too high, which does not match the maximum withstand voltage of the DC-DC step-down chip on the switch. When the input voltage is too high, the power input voltage may not be protected, but the DC-DC step-down chip of the switch may burn out due to the high voltage, causing the switch to malfunction. Therefore, it is urgent to add a voltage monitoring and control circuit to the switch circuit to solve the above problem. When the voltage is too high or too low, the power supply path can be directly cut off to protect the switch part. Summary of the Invention

[0003] The utility model addresses the problems of the prior art and provides a voltage monitoring control circuit to improve working stability and reliability. When the voltage is too high or too low, the power supply path of the power input circuit can be directly cut off to provide overvoltage protection and undervoltage protection. It can well protect the back-end circuit of the switch without relying on the power supply.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The utility model provides a voltage monitoring control circuit, which includes a power input circuit, a voltage monitoring circuit and an MCU control circuit;

[0006] The power input circuit includes a power input terminal JE1 and a transistor Q6 connected to the power input terminal JE1, and the base of the transistor Q6 is connected to the MCU control circuit;

[0007] There are multiple voltage monitoring circuits, and the voltage monitoring threshold of each voltage monitoring circuit is different;

[0008] Each voltage monitoring circuit includes a monitoring diode and a conductive switch. The output end of the power input circuit is connected to the MCU control circuit via the voltage monitoring circuit, and the conductive switch is connected to the MCU control circuit.

[0009] Among them, the voltage monitoring circuit includes an 8V voltage monitoring circuit; the 8V voltage monitoring circuit includes an 8V voltage monitoring diode D1, a transistor Q1, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a capacitor C1, the output end of the power input circuit is connected to the cathode of the 8V voltage monitoring diode D1, the anode of the 8V voltage monitoring diode D1 is connected to one end of the resistor R3, the other end of the resistor R3 is respectively connected to one end of the capacitor C1, one end of the resistor R4 and the base of the transistor Q1, the other end of the capacitor C1 is grounded, the other end of the resistor R4 and the emitter of the transistor Q1 are respectively grounded, the collector of the transistor Q1 is connected to one end of the resistor R2, the other end of the resistor R2 is respectively connected to the MCU control circuit and one end of the resistor R1, and the other end of the resistor R1 is connected to the load.

[0010] Among them, the voltage monitoring circuit includes a 10V voltage monitoring circuit; the 10V voltage monitoring circuit includes a 10V voltage monitoring diode D2, a transistor Q2, a resistor R9, a resistor R10, a resistor R11, a resistor R12 and a capacitor C7, the output end of the power input circuit is connected to the cathode of the 10V voltage monitoring diode D2, the anode of the 10V voltage monitoring diode D2 is connected to one end of the resistor R11, the other end of the resistor R11 is respectively connected to one end of the capacitor C7, one end of the resistor R12 and the base of the transistor Q2, the other end of the capacitor C7 is grounded, the other end of the resistor R12 and the emitter of the transistor Q2 are respectively grounded, the collector of the transistor Q2 is connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to the MCU control circuit and one end of the resistor R9, and the other end of the resistor R9 is connected to the load.

[0011] Among them, the voltage monitoring circuit includes a 13V voltage monitoring circuit; the 13V voltage monitoring circuit includes a 13V voltage zener diode D3, a transistor Q3, a resistor R5, a resistor R6, a resistor R7, a resistor R8 and a capacitor C6, the output end of the power input circuit is connected to the cathode of the 13V voltage zener diode D3, the anode of the 13V voltage zener diode D3 is connected to one end of the resistor R7, the other end of the resistor R7 is respectively connected to one end of the capacitor C6, one end of the resistor R8 and the base of the transistor Q3, the other end of the capacitor C6 is grounded, the other end of the resistor R8 and the emitter of the transistor Q3 are respectively grounded, the collector of the transistor Q3 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to the MCU control circuit and one end of the resistor R5, and the other end of the resistor R5 is connected to the load.

[0012] Among them, the voltage monitoring circuit includes a 14V voltage monitoring circuit; the 14V voltage monitoring circuit includes a 14V voltage zener diode D4, a transistor Q4, a resistor R13, a resistor R14, a resistor R15, a resistor R16 and a capacitor C8, the output end of the power input circuit is connected to the cathode of the 14V voltage zener diode D4, the anode of the 14V voltage zener diode D4 is connected to one end of the resistor R15, the other end of the resistor R15 is respectively connected to one end of the capacitor C8, one end of the resistor R16 and the base of the transistor Q4, the other end of the capacitor C8 is grounded, the other end of the resistor R16 and the emitter of the transistor Q4 are respectively grounded, the collector of the transistor Q4 is connected to one end of the resistor R14, the other end of the resistor R14 is respectively connected to the MCU control circuit and one end of the resistor R13, and the other end of the resistor R13 is connected to the load.

[0013] In which, the power input circuit also includes capacitor C2, capacitor C3, voltage zener diode D5, MOS transistor Q5, resistor R17 and resistor R18. One pin of the power input terminal JE1 is connected to one end of capacitor C2, one end of capacitor C3, and one end of resistor R17. The other end of resistor R17 is respectively connected to the cathode of voltage zener diode D5, the gate of MOS transistor Q5, and the collector of transistor Q6. The source of MOS transistor Q5 and the emitter of transistor Q6 are respectively grounded. The drain of MOS transistor Q5, the anode of voltage zener diode D5, the other end of capacitor C2, and the other end of capacitor C3 are respectively connected to the other pin of the power input terminal JE1. The base of transistor Q6 is connected to one end of resistor R18. The other end of resistor R18 is connected to the MCU control circuit.

[0014] The MCU control circuit includes a chip U1, and the model of the chip U1 is SH79F1612B.

[0015] Beneficial effects of the utility model:

[0016] The utility model is cleverly designed. During operation, a 12V input power supply is connected to the power input terminal JE1 and then supplied. The transistor Q6 is controlled by the MCU control circuit. By default, the base of the transistor Q6 is at a low level, and the transistor Q6 is turned off. The transistor Q6 is used to cut off the power input circuit. When the 12V input power supply starts to supply power, the voltage is monitored by multiple voltage monitoring circuits. If the voltage passing through the monitoring diode of the voltage monitoring circuit is within the voltage monitoring threshold, a current can be provided to the conductive switch to turn it on. After receiving the signal, the MCU control circuit can determine the range of the input voltage. If the input voltage range is within one of the multiple voltage monitoring thresholds, it is determined to be a safe voltage. If the input voltage range is greater than all preset voltage monitoring thresholds or less than all voltage monitoring thresholds, the MCU control circuit needs to control the transistor Q6 to cut off the power input circuit and thereby protect the back-end switch, thereby improving working stability and reliability. When the voltage is too high or too low, the power supply path of the power input circuit can be directly cut off, thereby playing the role of overvoltage protection and undervoltage protection, and can well protect the back-end circuit of the switch without relying on the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a circuit diagram of the power input circuit of the utility model.

[0018] Figure 2 This is a circuit diagram of the 8V voltage monitoring circuit of the present utility model.

[0019] Figure 3 This is a circuit diagram of a 10V voltage monitoring circuit of the present utility model.

[0020] Figure 4 This is a circuit diagram of the 13V voltage monitoring circuit of the present utility model.

[0021] Figure 5 This is a circuit diagram of the 14V voltage monitoring circuit of the present utility model.

[0022] Figure 6 This is a circuit diagram of the MCU control circuit of the present utility model. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments and drawings. The contents mentioned in the embodiments are not intended to limit the present invention. The present invention is described in detail below in conjunction with the drawings.

[0024] A voltage monitoring control circuit, such as Figures 1 to 6As shown, it includes a power input circuit, a voltage monitoring circuit and an MCU control circuit; wherein the MCU control circuit includes a chip U1, and the model of the chip U1 is SH79F1612B; the power input circuit includes a power input terminal JE1 and a transistor Q6 connected to the power input terminal JE1, and the base of the transistor Q6 is connected to the MCU control circuit; there are multiple voltage monitoring circuits, and the voltage monitoring threshold of each voltage monitoring circuit is different; each voltage monitoring circuit includes a monitoring diode and a conductive switch component, the output end of the power input circuit is connected to the MCU control circuit through the voltage monitoring circuit, and the conductive switch component is connected to the MCU control circuit. Specifically, the present invention is cleverly designed. During operation, a 12V input power supply is connected to the power input terminal JE1 and supplied. The transistor Q6 is controlled by the MCU control circuit. By default, the base of the transistor Q6 is at a low level, and the transistor Q6 is turned off. The transistor Q6 is used to cut off the power input circuit. When the 12V input power supply starts to supply power, the voltage is monitored by multiple voltage monitoring circuits. If the voltage passing through the monitoring diode of the voltage monitoring circuit is within the voltage monitoring threshold, a current can be provided to the conductive switch to turn it on. After receiving the signal, the MCU control circuit can determine the range of the input voltage. If the input voltage range is within one of the multiple voltage monitoring thresholds, it is determined to be a safe voltage. If the input voltage range is greater than all preset voltage monitoring thresholds or less than all voltage monitoring thresholds, the MCU control circuit needs to control the transistor Q6 to cut off the power input circuit and thereby protect the back-end switch, thereby improving operational stability and reliability. When the voltage is too high or too low, the power supply path of the power input circuit can be directly cut off, thereby providing overvoltage protection and undervoltage protection, and can effectively protect the back-end circuit of the switch without relying on the power supply.

[0025] In an embodiment of the present application, the power input circuit further includes a capacitor C2, a capacitor C3, a voltage zener diode D5, a MOS transistor Q5, a resistor R17, and a resistor R18. One pin of the power input terminal JE1 is connected to one end of the capacitor C2, one end of the capacitor C3, and one end of the resistor R17. The other end of the resistor R17 is respectively connected to the cathode of the voltage zener diode D5, the gate of the MOS transistor Q5, and the collector of the transistor Q6. The source of the MOS transistor Q5 and the emitter of the transistor Q6 are respectively grounded. The drain of the MOS transistor Q5, the anode of the voltage zener diode D5, the other end of the capacitor C2, and the other end of the capacitor C3 are respectively connected to the other pin of the power input terminal JE1. The base of the transistor Q6 is connected to one end of the resistor R18. The other end of the resistor R18 is connected to the MCU control circuit.

[0026] In an embodiment of the present application, the voltage monitoring circuit includes an 8V voltage monitoring circuit; the 8V voltage monitoring circuit includes an 8V voltage monitoring diode D1 (i.e., a monitoring diode), a transistor Q1 (i.e., a conductive switch), a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a capacitor C1, the output end of the power input circuit is connected to the cathode of the 8V voltage monitoring diode D1, the anode of the 8V voltage monitoring diode D1 is connected to one end of the resistor R3, the other end of the resistor R3 is respectively connected to one end of the capacitor C1, one end of the resistor R4 and the base of the transistor Q1, the other end of the capacitor C1 is grounded, the other end of the resistor R4 and the emitter of the transistor Q1 are respectively grounded, the collector of the transistor Q1 is connected to one end of the resistor R2, the other end of the resistor R2 is respectively connected to the MCU control circuit and one end of the resistor R1, and the other end of the resistor R1 is connected to the load.

[0027] In an embodiment of the present application, the voltage monitoring circuit includes a 10V voltage monitoring circuit; the 10V voltage monitoring circuit includes a 10V voltage monitoring diode D2 (i.e., a monitoring diode), a transistor Q2 (i.e., a conductive switch), a resistor R9, a resistor R10, a resistor R11, a resistor R12 and a capacitor C7, the output end of the power input circuit is connected to the cathode of the 10V voltage monitoring diode D2, the anode of the 10V voltage monitoring diode D2 is connected to one end of the resistor R11, the other end of the resistor R11 is respectively connected to one end of the capacitor C7, one end of the resistor R12 and the base of the transistor Q2, the other end of the capacitor C7 is grounded, the other end of the resistor R12 and the emitter of the transistor Q2 are respectively grounded, the collector of the transistor Q2 is connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to the MCU control circuit and one end of the resistor R9, and the other end of the resistor R9 is connected to the load.

[0028] In an embodiment of the present application, the voltage monitoring circuit includes a 13V voltage monitoring circuit; the 13V voltage monitoring circuit includes a 13V voltage monitoring diode D3 (i.e., a monitoring diode), a transistor Q3 (i.e., a conductive switch), a resistor R5, a resistor R6, a resistor R7, a resistor R8 and a capacitor C6, the output end of the power input circuit is connected to the cathode of the 13V voltage monitoring diode D3, the anode of the 13V voltage monitoring diode D3 is connected to one end of the resistor R7, the other end of the resistor R7 is respectively connected to one end of the capacitor C6, one end of the resistor R8 and the base of the transistor Q3, the other end of the capacitor C6 is grounded, the other end of the resistor R8 and the emitter of the transistor Q3 are respectively grounded, the collector of the transistor Q3 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to the MCU control circuit and one end of the resistor R5, and the other end of the resistor R5 is connected to the load.

[0029] In an embodiment of the present application, the voltage monitoring circuit includes a 14V voltage monitoring circuit; the 14V voltage monitoring circuit includes a 14V voltage monitoring diode D4 (i.e., a monitoring diode), a transistor Q4 (i.e., a conductive switch), a resistor R13, a resistor R14, a resistor R15, a resistor R16 and a capacitor C8, the output end of the power input circuit is connected to the cathode of the 14V voltage monitoring diode D4, the anode of the 14V voltage monitoring diode D4 is connected to one end of the resistor R15, the other end of the resistor R15 is respectively connected to one end of the capacitor C8, one end of the resistor R16 and the base of the transistor Q4, the other end of the capacitor C8 is grounded, the other end of the resistor R16 and the emitter of the transistor Q4 are respectively grounded, the collector of the transistor Q4 is connected to one end of the resistor R14, the other end of the resistor R14 is respectively connected to the MCU control circuit and one end of the resistor R13, and the other end of the resistor R13 is connected to the load.

[0030] Specifically, the specific working principle of the embodiment of the present application is as follows: when the 12V input power supply is connected through the power input terminal JE1 and supplied, it will first be filtered by capacitors C2 and C3, and then pass through parallel resistors R17. Resistors R17 are connected in parallel with the 12V voltage regulator diode D5, the gate of the NMOS tube Q5, and the transistor Q6. When 12V is input, the voltage is limited by the resistor R17 and reaches the voltage regulator diode D5 and the NMOS tube Q5 at the same time. After the voltage regulator diode D5 breaks down, a stable 12V voltage is provided to the gate of the NMOS tube Q5, controlling the 12V negative electrode of the NMOS tube Q5 to turn on. At this time, the circuit starts to power on, and the transistor Q6 is driven by the MCU control circuit. By default, the base of the transistor Q6 is at a low level, and the transistor Q6 is turned off. Its operation is fully controlled by the MCU control circuit (when protection and circuit disconnection are required);

[0031] When the 12V power supply starts to supply power, the voltage monitoring circuit is divided into 4 paths (8V voltage monitoring circuit, 10V voltage monitoring circuit, 13V voltage monitoring circuit and 14V voltage monitoring circuit), which correspond to the 4 I / O ports (I / O_10V, I / O_13V, I / O_14V) of the MCU control circuit respectively to detect whether the voltage is higher than the set value. When the 12V power supply starts to supply power, assuming that the power supply voltage is lower than 10V and higher than 8V, the 8V Zener diode D1 will be broken down. After the breakdown, the remaining voltage of less than 2V provides current to the base of the NPN transistor Q1 through the resistor R3, turning on the transistor Q1. At this time, the collector and emitter of the transistor Q1 are connected and are grounded, which will If the signal pin (I / O_8V) connected to the I / O port of the MCU control circuit is pulled low, and the power supply voltage is higher than 8V and lower than 10V, the 10V Zener diode, 13V Zener diode, and 14V Zener diode will all fail to conduct, and the signal pins I / O_10V, I / O_13V, and I / O_14V will all be high (the default is high). At this time, the MCU control circuit can know the approximate range of the input voltage based on the I / O port pin level of the connected voltage monitoring circuit, and thus determine whether to protect the back-end circuit; the operation of the other three voltage monitoring circuits (10V voltage monitoring circuit, 13V voltage monitoring circuit, and 14V voltage monitoring circuit) is the same.

[0032] When the input voltage is higher than the preset value, for example, the power supply voltage reaches 15V, and the maximum withstand voltage of the switch DC-DC step-down chip is 17V, the input voltage will cause the 8V Zener diode D1, 10V Zener diode D2, 13V Zener diode D3, and 14V Zener diode D4 of the four voltage monitoring circuits (8V voltage monitoring circuit, 10V voltage monitoring circuit, 13V voltage monitoring circuit, and 14V voltage monitoring circuit) to break down. Transistor Q3 and transistor Q4 pull down the monitoring pins I / O_8V, I / O_10V, I / O_13V, and I / O_14V of the MCU control circuit. At this time, when the MCU control circuit receives low voltage signals from the monitoring pins I / O_8V, I / O_10V, I / O_13V, and I / O_14V of the four voltage monitoring circuits, the control pin at the base of transistor Q6 is pulled high, allowing current to flow, turning on transistor Q6 and lowering the gate level of NMOS Q5 on the 12V negative control circuit, disconnecting the negative terminal of the power supply and stopping power supply to protect the back-end switch circuit.

[0033] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention is disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of the above-disclosed technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technology of the present invention, which do not depart from the content of the technical solution of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. A voltage monitoring control circuit, characterized in that: Including power input circuit, voltage monitoring circuit and MCU control circuit; The power input circuit includes a power input terminal JE1 and a transistor Q6 connected to the power input terminal JE1, and the base of the transistor Q6 is connected to the MCU control circuit; There are multiple voltage monitoring circuits, and the voltage monitoring threshold of each voltage monitoring circuit is different; Each voltage monitoring circuit includes a monitoring diode and a conductive switch. The output end of the power input circuit is connected to the MCU control circuit via the voltage monitoring circuit, and the conductive switch is connected to the MCU control circuit.

2. The voltage monitoring control circuit according to claim 1, wherein: The voltage monitoring circuit includes an 8V voltage monitoring circuit; the 8V voltage monitoring circuit includes an 8V voltage zener diode D1, a transistor Q1, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a capacitor C1, the output end of the power input circuit is connected to the cathode of the 8V voltage zener diode D1, the anode of the 8V voltage zener diode D1 is connected to one end of the resistor R3, the other end of the resistor R3 is respectively connected to one end of the capacitor C1, one end of the resistor R4 and the base of the transistor Q1, the other end of the capacitor C1 is grounded, the other end of the resistor R4 and the emitter of the transistor Q1 are respectively grounded, the collector of the transistor Q1 is connected to one end of the resistor R2, the other end of the resistor R2 is respectively connected to the MCU control circuit and one end of the resistor R1, and the other end of the resistor R1 is connected to the load.

3. The voltage monitoring control circuit according to claim 1, wherein: The voltage monitoring circuit includes a 10V voltage monitoring circuit; the 10V voltage monitoring circuit includes a 10V voltage zener diode D2, a transistor Q2, a resistor R9, a resistor R10, a resistor R11, a resistor R12 and a capacitor C7, the output end of the power input circuit is connected to the cathode of the 10V voltage zener diode D2, the anode of the 10V voltage zener diode D2 is connected to one end of the resistor R11, the other end of the resistor R11 is respectively connected to one end of the capacitor C7, one end of the resistor R12 and the base of the transistor Q2, the other end of the capacitor C7 is grounded, the other end of the resistor R12 and the emitter of the transistor Q2 are respectively grounded, the collector of the transistor Q2 is connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to the MCU control circuit and one end of the resistor R9, and the other end of the resistor R9 is connected to the load.

4. The voltage monitoring control circuit according to claim 1, wherein: The voltage monitoring circuit includes a 13V voltage monitoring circuit; the 13V voltage monitoring circuit includes a 13V voltage zener diode D3, a transistor Q3, a resistor R5, a resistor R6, a resistor R7, a resistor R8 and a capacitor C6, the output end of the power input circuit is connected to the cathode of the 13V voltage zener diode D3, the anode of the 13V voltage zener diode D3 is connected to one end of the resistor R7, the other end of the resistor R7 is respectively connected to one end of the capacitor C6, one end of the resistor R8 and the base of the transistor Q3, the other end of the capacitor C6 is grounded, the other end of the resistor R8 and the emitter of the transistor Q3 are respectively grounded, the collector of the transistor Q3 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to the MCU control circuit and one end of the resistor R5, and the other end of the resistor R5 is connected to the load.

5. The voltage monitoring control circuit according to claim 1, wherein: The voltage monitoring circuit includes a 14V voltage monitoring circuit; the 14V voltage monitoring circuit includes a 14V voltage zener diode D4, a transistor Q4, a resistor R13, a resistor R14, a resistor R15, a resistor R16 and a capacitor C8, the output end of the power input circuit is connected to the cathode of the 14V voltage zener diode D4, the anode of the 14V voltage zener diode D4 is connected to one end of the resistor R15, the other end of the resistor R15 is respectively connected to one end of the capacitor C8, one end of the resistor R16 and the base of the transistor Q4, the other end of the capacitor C8 is grounded, the other end of the resistor R16 and the emitter of the transistor Q4 are respectively grounded, the collector of the transistor Q4 is connected to one end of the resistor R14, the other end of the resistor R14 is respectively connected to the MCU control circuit and one end of the resistor R13, and the other end of the resistor R13 is connected to the load.

6. The voltage monitoring control circuit according to claim 1, wherein: The power input circuit also includes a capacitor C2, a capacitor C3, a voltage-stabilizing diode D5, a MOS transistor Q5, a resistor R17, and a resistor R18. One pin of the power input terminal JE1 is connected to one end of the capacitor C2, one end of the capacitor C3, and one end of the resistor R17. The other end of the resistor R17 is respectively connected to the cathode of the voltage-stabilizing diode D5, the gate of the MOS transistor Q5, and the collector of the transistor Q6. The source of the MOS transistor Q5 and the emitter of the transistor Q6 are respectively grounded. The drain of the MOS transistor Q5, the anode of the voltage-stabilizing diode D5, the other end of the capacitor C2, and the other end of the capacitor C3 are respectively connected to the other pin of the power input terminal JE1. The base of the transistor Q6 is connected to one end of the resistor R18. The other end of the resistor R18 is connected to the MCU control circuit.

7. The voltage monitoring control circuit according to claim 1, wherein: The MCU control circuit includes a chip U1 , and the model of the chip U1 is SH79F1612B.

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