Emergency protection circuit of a monitor

Abstract

The invention discloses an emergency protection circuit of a monitor, and relates to the field of safety protection. The emergency protection circuit of the monitor comprises: a switch power supply unit, which is used for introducing a power supply, controlling a first field effect tube to be turned on through a second field effect tube, and supplying voltage to a chip; compared with the prior art, the invention has the following beneficial effects: the invention detects power supply information by setting a detection feedback unit, and the feedback PWM signal cooperates with a cut-off voltage stabilizing and power-discharging unit, which, on the one hand, cuts off the on-switch of the starting switch power supply unit, and on the other hand, constructs a voltage stabilizing and power supply of the switch power supply unit; when the power supply fails, the PWM signal prompts the cut-off voltage stabilizing and power-discharging unit to quickly discharge the voltage on the switch power supply unit and a chip storage device, and quickly completes the power discharging; the cut-off voltage stabilizing and power-discharging unit realizes three functions of cut-off, voltage stabilization, and power discharging based on the PWM signal fed back by the detection feedback unit, and has a compact structure and uses fewer devices.

Description

Technical Field

[0001] The invention relates to the field of safety protection, in particular to an emergency protection circuit of a monitor. Background Art

[0002] As a medical device, the electrical safety performance of the monitor is extremely important. In the case of a sudden power outage, due to the presence of capacitors, inductors and other energy storage devices in the monitor circuit, the voltage will not quickly become 0 when the power is off. When the voltage becomes 0, the chip will stop working directly, and there will be no communication abnormalities. The voltage gradually decreases from the normal value to 0. During the power-off process, the chip (such as the main control chip MM32F3270, the encryption authentication chip GX2431, the Ethernet communication chip, etc.) may be in an unstable state, and there may be communication abnormalities, resulting in data loss. The patient's physiological parameters are questionable and need to be improved. Summary of the invention

[0003] The purpose of the present invention is to provide an emergency protection circuit for a monitor to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An emergency protection circuit for a monitor, comprising:

[0006] The switch power supply unit is used to introduce a power supply, control the first field effect tube to conduct through the second field effect tube, and supply voltage to the chip;

[0007] The detection feedback unit is used to detect the current output to the chip to obtain a PWM signal inversely proportional to the duty cycle, and feed it back to the cut-off voltage stabilization and pressure relief unit;

[0008] The cut-off voltage stabilizing and pressure relief unit is used to receive a PWM signal to control the cut-off of the second field effect tube; receive a PWM signal to control the conduction frequency of the first field effect tube so that the voltage output from the switch power supply unit to the chip is stable; receive a PWM signal to discharge the voltage on the switch power supply unit and the chip memory device when the power supply source is powered off;

[0009] The output end of the switch power supply unit is connected to the input end of the detection feedback unit, the output end of the detection feedback unit is connected to the input end of the cut-off voltage stabilizing and pressure relief unit, the first output end of the cut-off voltage stabilizing and pressure relief unit is connected to the first input end of the switch power supply unit, the second output end of the cut-off voltage stabilizing and pressure relief unit is connected to the second input end of the switch power supply unit, and the third output end of the cut-off voltage stabilizing and pressure relief unit is connected to the third input end of the switch power supply unit.

[0010] As a further solution of the present invention: the switching power supply unit includes a first resistor, a first field effect transistor, a second field effect transistor, a first diode, a second resistor, a second capacitor, and a fourth transistor. The drain of the first field effect transistor is connected to one end of the first resistor and the power supply, the other end of the first resistor is connected to the source of the second field effect transistor, the gate of the second field effect transistor is connected to the second output end of the cut-off voltage stabilizing and pressure relief unit, the drain of the second field effect transistor is connected to the positive electrode of the first diode, the negative electrode of the first diode is connected to the gate of the first field effect transistor and the first output end of the cut-off voltage stabilizing and pressure relief unit, the source of the first field effect transistor is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the second capacitor, the collector of the first transistor, and one end of the chip, the two ends of the second resistor are the input ends of the detection feedback unit, the other end of the second capacitor is grounded, the emitter of the fourth transistor is grounded, the base of the fourth transistor is connected to the third output end of the cut-off voltage stabilizing and pressure relief unit, and the other end of the chip is grounded.

[0011] As a further solution of the present invention: the detection feedback unit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first amplifier, a second inverter, a seventh resistor, and a first capacitor, one end of the third resistor is connected to the output end of the switch power supply unit, one end of the fourth resistor is connected to the output end of the switch power supply unit, the other end of the third resistor is connected to one end of the sixth resistor and the in-phase end of the first amplifier, the other end of the fourth resistor is connected to one end of the fifth resistor and the inverting end of the first amplifier, the other end of the fifth resistor is grounded, the output end of the first amplifier is connected to the other end of the sixth resistor and the power supply end of the second inverter, the output end of the second inverter is connected to one end of the seventh resistor and the input end of the cut-off voltage stabilizing and leakage unit, the input end of the second inverter is connected to the other end of the seventh resistor and one end of the first capacitor, and the other end of the first capacitor is grounded.

[0012] As a further solution of the present invention: the cut-off voltage stabilizing and power discharging unit comprises:

[0013] The voltage stabilizing subunit is used to control the conduction frequency of the first field effect tube after receiving the PWM signal, change the voltage output to the chip, and build a regulated output;

[0014] The cut-off subunit is used to receive the PWM signal from the voltage stabilizing subunit, amplify and filter it, obtain the control signal, and control the second field effect tube to cut off;

[0015] The discharge electronic unit is used to detect the control signal generated based on the PWM signal. When the voltage of the control signal reaches a threshold, the switch power supply unit and the chip connection point are grounded to discharge the pressure.

[0016] The input end of the voltage stabilizing subunit is connected to the output end of the detection feedback unit, the first output end of the voltage stabilizing subunit is connected to the first input end of the switch power supply unit, the second output end of the voltage stabilizing subunit is connected to the input end of the cutoff subunit, the output end of the cutoff subunit is connected to the second input end of the switch power supply unit and the input end of the leakage subunit, and the output end of the leakage subunit is connected to the third input end of the switch power supply unit.

[0017] As a further solution of the present invention: the voltage stabilizing subunit includes a second diode and a fourth diode, the anode of the second diode is connected to the output end of the detection feedback unit, the cathode of the second diode is connected to the anode of the fourth diode and the input end of the cut-off subunit, and the cathode of the fourth diode is connected to the first input end of the switching power supply unit.

[0018] As a further solution of the present invention: the cutoff subunit includes a ninth resistor, a third transistor, and a third capacitor, one end of the ninth resistor is connected to the power supply, the other end of the ninth resistor is connected to the collector of the third transistor, the base of the third transistor is connected to the second output end of the voltage stabilizing subunit, the emitter of the third transistor is connected to one end of the third capacitor, the second input end of the switching power supply unit, and the input end of the leakage subunit, and the other end of the third capacitor is grounded.

[0019] As a further solution of the present invention: the leakage sub-unit includes an eighth resistor, a third diode, a first thyristor, a tenth resistor, and a battery, one end of the eighth resistor is connected to the output end of the cut-off sub-unit, the other end of the eighth resistor is connected to the cathode of the third diode, the anode of the third diode is connected to the control electrode of the first thyristor, the cathode of the first thyristor is connected to the third input end of the switch power supply unit, the anode of the first thyristor is connected to one end of the tenth resistor, the other end of the tenth resistor is connected to the positive electrode of the battery, and the negative electrode of the battery is grounded.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention detects power supply information by setting a detection feedback unit, and the feedback PWM signal cooperates with the cut-off voltage stabilization and power discharge unit to cut off the on-switch of the starting switch power supply unit on the one hand, and to establish a regulated power supply for the switch power supply unit on the other hand; when the power supply source is powered off, the PWM signal prompts the cut-off voltage stabilization and power discharge unit to quickly discharge the voltage on the switch power supply unit and the chip storage device, and quickly completes the power discharge, thereby avoiding communication anomalies in the chip during the power-off process in which the chip voltage gradually decreases from a normal value to 0, resulting in data loss; the cut-off voltage stabilization and power discharge unit realizes the three functions of cut-off, voltage stabilization, and power discharge based on the PWM signal fed back by the detection feedback unit, with a compact structure and few devices used. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The utility model is a schematic diagram of an emergency protection circuit of a monitor.

[0022] Figure 2 The utility model discloses a circuit diagram of an emergency protection circuit of a monitor.

[0023] Figure 3 This is the circuit diagram of the switching power supply unit.

[0024] Figure 4 This is the circuit diagram of the detection feedback unit.

[0025] Figure 5 It is a circuit diagram of the cut-off voltage-stabilizing and leakage-discharging unit. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] See also Figure 1 and Figure 2 , an emergency protection circuit of a monitor, comprising:

[0028] The switch power supply unit 1 is used to introduce the power supply VCC, control the first field effect tube V1 to be turned on through the second field effect tube V2, and supply voltage to the chip;

[0029] The detection feedback unit 2 is used to detect the current output to the chip to obtain a PWM signal inversely proportional to the duty cycle, and feed it back to the cut-off voltage stabilization and pressure relief unit 3;

[0030] The cut-off voltage stabilizing and pressure relief unit 3 is used to receive a PWM signal to control the cut-off of the second field effect tube V2; receive a PWM signal to control the conduction frequency of the first field effect tube V1, so that the voltage output from the switch power supply unit 1 to the chip is stable; receive a PWM signal, and when the power supply VCC is powered off, discharge the voltage on the switch power supply unit 1 and the chip memory device;

[0031] The output end of the switch power supply unit 1 is connected to the input end of the detection feedback unit 2, the output end of the detection feedback unit 2 is connected to the input end of the cut-off voltage stabilizing and pressure relief unit 3, the first output end of the cut-off voltage stabilizing and pressure relief unit 3 is connected to the first input end of the switch power supply unit 1, the second output end of the cut-off voltage stabilizing and pressure relief unit 3 is connected to the second input end of the switch power supply unit 1, and the third output end of the cut-off voltage stabilizing and pressure relief unit 3 is connected to the third input end of the switch power supply unit 1.

[0032] In this implementation column: please refer to Figure 2 and Figure 3The switch power supply unit 1 includes a first resistor R1, a first field effect transistor V1, a second field effect transistor V2, a first diode D1, a second resistor R2, a second capacitor C2, and a fourth transistor V4. The drain of the first field effect transistor V1 is connected to one end of the first resistor R1 and the power supply VCC, the other end of the first resistor R1 is connected to the source of the second field effect transistor V2, the gate of the second field effect transistor V2 is connected to the second output end of the cut-off voltage stabilizing and pressure relief unit 3, the drain of the second field effect transistor V2 is connected to the anode of the first diode D1, and the gate of the first diode D1 is connected to the gate of the second field effect transistor V2. The negative electrode is connected to the gate of the first field effect transistor V1 and the first output end of the cut-off voltage stabilizing and pressure relief unit 3, the source of the first field effect transistor V1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the second capacitor C2, the collector of the first transistor, and one end of the chip, the two ends of the second resistor R2 are the input ends of the detection feedback unit 2, the other end of the second capacitor C2 is grounded, the emitter of the fourth transistor V4 is grounded, the base of the fourth transistor V4 is connected to the third output end of the cut-off voltage stabilizing and pressure relief unit 3, and the other end of the chip is grounded.

[0033] The power supply VCC voltage is input. Initially, the gate of the second field effect transistor V2 (PMOS) is at a low level, the second field effect transistor V2 is turned on, and the gate of the first field effect transistor V1 is at a high level through the first diode D1. The first field effect transistor V1 is turned on, and the power supply VCC supplies power to the chip through the first field effect transistor V1, the second resistor R2, and the second capacitor C2.

[0034] In another embodiment, the second capacitor C2 can be omitted. The second capacitor C2 is used to ensure voltage stability. After being controlled by the cut-off voltage stabilizing and current discharging unit, the output voltage of the switching power supply unit 1 is ensured to be stable.

[0035] In this implementation column: please refer to Figure 2 and Figure 4The detection feedback unit 2 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first amplifier U1, a second inverter U2, a seventh resistor R7, and a first capacitor C1. One end of the third resistor R3 is connected to the output end of the switch power supply unit 1, one end of the fourth resistor R4 is connected to the output end of the switch power supply unit 1, the other end of the third resistor R3 is connected to one end of the sixth resistor R6 and the non-inverting end of the first amplifier U1, the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5 and the inverting end of the first amplifier U1, the other end of the fifth resistor R5 is grounded, the output end of the first amplifier U1 is connected to the other end of the sixth resistor R6 and the power supply end of the second inverter U2, the output end of the second inverter U2 is connected to one end of the seventh resistor R7 and the input end of the cut-off voltage stabilizing and leakage unit, the input end of the second inverter U2 is connected to the other end of the seventh resistor R7 and one end of the first capacitor C1, and the other end of the first capacitor C1 is grounded.

[0036] The third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the first amplifier U1 form a differential amplifier circuit, which collects the voltage difference across the second resistor R2 and amplifies it to reflect the voltage output to the chip. The greater the current flowing through the chip, the greater the current on the second resistor R2, the greater the voltage difference across the second resistor R2, and the greater the voltage output from the output end of the first amplifier U1, and vice versa. The ratio of the third resistor R3 to the sixth resistor R6 is equal to the ratio of the fourth resistor R4 to the fifth resistor R5. When the power is just turned on, there is no voltage on the first capacitor C1, the input end of the second inverter U2 is low level, the second inverter U2 outputs high level, and the first capacitor C1 is charged through the seventh resistor R7. When the first capacitor C1 is charged to a high level, the input end of the second inverter U2 is high level, the second inverter U2 outputs low level, the first capacitor C1 is discharged through the seventh resistor R7, and becomes low level again, and the operation is repeated. The output end of the second inverter U2 forms a PWM signal. Based on the fact that the output high level of the second inverter U2 is equal to the power supply voltage, the first capacitor C1 is charged through the seventh resistor R7 and discharged through the seventh resistor R7. The larger the output high level during charging, the faster the charging speed of the first capacitor C1, and the shorter the high level time of the PWM signal, while the discharge speed of the first capacitor C1 remains unchanged. Therefore, the larger the current flowing through the second resistor R2, the larger the power supply voltage of the second amplifier, and the smaller the duty cycle of the formed PWM signal. Conversely, the smaller the current flowing through the second resistor R2, the larger the duty cycle of the formed PWM signal.

[0037] In another embodiment, the third resistor R3 and the fourth resistor R4 may have the same resistance value, and the fifth resistor R5 and the sixth resistor R6 may have the same resistance value.

[0038] In this implementation column: please refer to Figure 2 and Figure 5 , the cut-off voltage stabilizing and discharge unit includes:

[0039] The voltage stabilizing subunit is used to control the conduction frequency of the first field effect tube V1 after receiving the PWM signal, change the voltage output to the chip, and build a regulated output;

[0040] The cut-off subunit is used to receive the PWM signal from the voltage stabilizing subunit, amplify and filter it, and then obtain the control signal to control the second field effect tube V2 to cut off;

[0041] The discharge sub-unit is used to detect the control signal generated based on the PWM signal, and when the voltage of the control signal reaches a threshold, the switch power supply unit 1 and the chip connection point are grounded to discharge the pressure;

[0042] The input end of the voltage stabilizing subunit is connected to the output end of the detection feedback unit 2, the first output end of the voltage stabilizing subunit is connected to the first input end of the switch power supply unit 1, the second output end of the voltage stabilizing subunit is connected to the input end of the cutoff subunit, the output end of the cutoff subunit is connected to the second input end of the switch power supply unit 1 and the input end of the leakage subunit, and the output end of the leakage subunit is connected to the third input end of the switch power supply unit 1.

[0043] In this implementation column: please refer to Figure 2 and Figure 5 The voltage stabilizing subunit includes a second diode D2 and a fourth diode D4, the anode of the second diode D2 is connected to the output end of the detection feedback unit 2, the cathode of the second diode D2 is connected to the anode of the fourth diode D4 and the input end of the cut-off subunit, and the cathode of the fourth diode D4 is connected to the first input end of the switch power supply unit 1.

[0044] After the PWM signal is input, it is output to the gate of the first field effect tube V1 through the second diode D2 and the fourth diode D4 to control the conduction frequency of the first field effect tube V1 and construct a regulated output. When the voltage flowing through the first field effect tube V1 is too large, the voltage on the second resistor R2 is too large, the duty cycle of the output PWM signal is reduced, the conduction frequency of the first field effect tube V1 is reduced, and the output voltage is reduced; conversely, when the voltage flowing through the first field effect tube V1 is too low, the duty cycle of the output PWM signal is increased, the conduction frequency of the first field effect tube V1 is increased, and the output voltage is increased; in this way, a regulated output is constructed to meet the requirements of chip regulated power supply.

[0045] In another embodiment, a resistor may be added to reduce the voltage output to the gate of the first field effect transistor V1 , or an amplifier circuit may be added to increase the voltage output to the gate of the first field effect transistor V1 .

[0046] In this implementation column: please refer to Figure 2 and Figure 5 The cut-off subunit includes a ninth resistor R9, a third triode V3, and a third capacitor C3. One end of the ninth resistor R9 is connected to the power supply VCC, the other end of the ninth resistor R9 is connected to the collector of the third triode V3, the base of the third triode V3 is connected to the second output end of the voltage stabilizing subunit, the emitter of the third triode V3 is connected to one end of the third capacitor C3, the second input end of the switching power supply unit 1, and the input end of the leakage subunit, and the other end of the third capacitor C3 is grounded.

[0047] After the PWM signal is input, it is input to the third transistor V3 through the second diode D2. After being amplified by the third transistor V3, it is filtered by the third capacitor C3 and becomes a stable DC voltage, so that the gate of the second field effect transistor V2 becomes a high level, and the second field effect transistor V2 is cut off, avoiding the PWM signal from entering the first field effect transistor V1 to control the voltage to build a regulated output, and the voltage passes through the second field effect transistor V2 to affect the voltage regulation.

[0048] In another embodiment: the power supply VCC is used as the working voltage of the cut-off subunit, and the battery E1 can also be used as the working voltage of the cut-off subunit.

[0049] In this implementation column: please refer to Figure 2 and Figure 5 The leakage sub-unit includes an eighth resistor R8, a third diode D3, a first thyristor Z1, a tenth resistor R10, and a battery E1. One end of the eighth resistor R8 is connected to the output end of the cutoff sub-unit, the other end of the eighth resistor R8 is connected to the cathode of the third diode D3, the anode of the third diode D3 is connected to the control electrode of the first thyristor Z1, the cathode of the first thyristor Z1 is connected to the third input end of the switch power supply unit 1, the anode of the first thyristor Z1 is connected to one end of the tenth resistor R10, the other end of the tenth resistor R10 is connected to the anode of the battery E1, and the cathode of the battery E1 is grounded.

[0050] When the power supply VCC is powered off, the power supply VCC is set at the left connection point of the second resistor R2, and the second capacitor C2 and the energy storage device of the chip are set at the right connection point of the second resistor R2, resulting in a sharp decrease in the current flowing through the second resistor R2, and the voltage on the right side of the second resistor R2 is quickly changed to be higher than the voltage on the left side. In this process, the voltage at the power supply end of the second inverter U2 is sharply reduced, and the output PWM duty cycle is sharply increased, so that the control signal voltage generated after the PWM signal passes through the second diode D2, the third transistor V3, and the third capacitor C3 is sharply increased, and the third diode D3 is turned on, triggering the first thyristor Z1 to turn on, the common point A becomes a high level, and the fourth transistor V4 is turned on, quickly discharging the voltage on the second capacitor C2 and the energy storage device of the chip, so as to avoid the chip from having communication anomalies and causing data loss during the power-off process when the chip voltage gradually decreases from the normal value to 0. The chip can be the main control chip of the monitoring instrument, the encryption authentication chip, the Ethernet communication chip, the USB interface chip, etc., without restriction.

[0051] In another embodiment: when the power supply VCC operates normally, the battery E1 can be charged by the power supply VCC.

[0052] The working principle of the present invention is: the switch power supply unit 1 is used to introduce the power supply VCC, and control the first field effect tube V1 to be turned on through the second field effect tube V2 to supply voltage to the chip; the detection feedback unit 2 is used to detect the current output to the chip to obtain a PWM signal inversely proportional to the duty cycle, and feed it back to the cut-off voltage stabilizing and pressure relief unit 3; the cut-off voltage stabilizing and pressure relief unit 3 is used to receive the PWM signal to control the cut-off of the second field effect tube V2; receive the PWM signal to control the conduction frequency of the first field effect tube V1, so that the voltage output from the switch power supply unit 1 to the chip is stable; receive the PWM signal, and when the power supply VCC is powered off, discharge the voltage on the switch power supply unit 1 and the chip storage device.

[0053] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered as exemplary and non-restrictive in all respects.

[0054] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An emergency protection circuit for a monitor, characterized in that: The emergency protection circuit of the monitor includes: The switch power supply unit is used to introduce a power supply, control the first field effect tube to conduct through the second field effect tube, and supply voltage to the chip; The detection feedback unit is used to detect the current output to the chip to obtain a PWM signal inversely proportional to the duty cycle, and feed it back to the cut-off voltage stabilization and pressure relief unit; The cut-off voltage stabilizing and pressure relief unit is used to receive a PWM signal to control the cut-off of the second field effect tube; receive a PWM signal to control the conduction frequency of the first field effect tube so that the voltage output from the switch power supply unit to the chip is stable; receive a PWM signal to discharge the voltage on the switch power supply unit and the chip memory device when the power supply source is powered off; The output end of the switch power supply unit is connected to the input end of the detection feedback unit, the output end of the detection feedback unit is connected to the input end of the cut-off voltage stabilizing and pressure relief unit, the first output end of the cut-off voltage stabilizing and pressure relief unit is connected to the first input end of the switch power supply unit, the second output end of the cut-off voltage stabilizing and pressure relief unit is connected to the second input end of the switch power supply unit, and the third output end of the cut-off voltage stabilizing and pressure relief unit is connected to the third input end of the switch power supply unit; The cut-off voltage stabilizing and discharge unit includes: The voltage stabilizing subunit is used to control the conduction frequency of the first field effect tube after receiving the PWM signal, change the voltage output to the chip, and build a regulated output; The cut-off subunit is used to receive the PWM signal from the voltage stabilizing subunit, amplify and filter it, obtain the control signal, and control the second field effect tube to cut off; The discharge electronic unit is used to detect the control signal generated based on the PWM signal. When the voltage of the control signal reaches a threshold, the switch power supply unit and the chip connection point are grounded to discharge the pressure. The input end of the voltage stabilizing subunit is connected to the output end of the detection feedback unit, the first output end of the voltage stabilizing subunit is connected to the first input end of the switch power supply unit, the second output end of the voltage stabilizing subunit is connected to the input end of the cutoff subunit, the output end of the cutoff subunit is connected to the second input end of the switch power supply unit and the input end of the leakage subunit, and the output end of the leakage subunit is connected to the third input end of the switch power supply unit.

2. The emergency protection circuit of the monitor according to claim 1, characterized in that: The switch power supply unit includes a first resistor, a first field effect transistor, a second field effect transistor, a first diode, a second resistor, a second capacitor, and a fourth transistor. The drain of the first field effect transistor is connected to one end of the first resistor and the power supply, the other end of the first resistor is connected to the source of the second field effect transistor, the gate of the second field effect transistor is connected to the second output end of the cut-off voltage stabilizing and pressure relief unit, the drain of the second field effect transistor is connected to the positive electrode of the first diode, the negative electrode of the first diode is connected to the gate of the first field effect transistor and the first output end of the cut-off voltage stabilizing and pressure relief unit, the source of the first field effect transistor is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the second capacitor, the collector of the first transistor, and one end of the chip, the two ends of the second resistor are the input ends of the detection feedback unit, the other end of the second capacitor is grounded, the emitter of the fourth transistor is grounded, the base of the fourth transistor is connected to the third output end of the cut-off voltage stabilizing and pressure relief unit, and the other end of the chip is grounded.

3. The emergency protection circuit of the monitor according to claim 1, characterized in that: The detection feedback unit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first amplifier, a second inverter, a seventh resistor, and a first capacitor. One end of the third resistor is connected to the output end of the switch power supply unit, one end of the fourth resistor is connected to the output end of the switch power supply unit, the other end of the third resistor is connected to one end of the sixth resistor and the in-phase end of the first amplifier, the other end of the fourth resistor is connected to one end of the fifth resistor and the inverting end of the first amplifier, the other end of the fifth resistor is grounded, the output end of the first amplifier is connected to the other end of the sixth resistor and the power supply end of the second inverter, the output end of the second inverter is connected to one end of the seventh resistor and the input end of the cut-off voltage stabilizing and leakage unit, the input end of the second inverter is connected to the other end of the seventh resistor and one end of the first capacitor, and the other end of the first capacitor is grounded.

4. The emergency protection circuit of the monitor according to claim 1, characterized in that: The voltage stabilizing subunit includes a second diode and a fourth diode, the anode of the second diode is connected to the output end of the detection feedback unit, the cathode of the second diode is connected to the anode of the fourth diode and the input end of the cutoff subunit, and the cathode of the fourth diode is connected to the first input end of the switch power supply unit.

5. The emergency protection circuit of the monitor according to claim 4, characterized in that: The cut-off subunit includes a ninth resistor, a third transistor, and a third capacitor. One end of the ninth resistor is connected to the power supply, the other end of the ninth resistor is connected to the collector of the third transistor, the base of the third transistor is connected to the second output end of the voltage stabilizing subunit, the emitter of the third transistor is connected to one end of the third capacitor, the second input end of the switching power supply unit, and the input end of the leakage subunit, and the other end of the third capacitor is grounded.

6. The emergency protection circuit of the monitor according to any one of claims 1, 4 and 5, characterized in that: The leakage sub-unit includes an eighth resistor, a third diode, a first thyristor, a tenth resistor, and a battery. One end of the eighth resistor is connected to the output end of the cutoff sub-unit, the other end of the eighth resistor is connected to the cathode of the third diode, the anode of the third diode is connected to the control electrode of the first thyristor, the cathode of the first thyristor is connected to the third input end of the switch power supply unit, the anode of the first thyristor is connected to one end of the tenth resistor, the other end of the tenth resistor is connected to the positive electrode of the battery, and the negative electrode of the battery is grounded.

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