A protection device

Abstract

The embodiment of the present application discloses a protection device, which comprises a first detection circuit and a switch circuit; an input end of the first detection circuit is electrically connected with a power supply, an output end of the first detection circuit is electrically connected with a control end of the switch circuit, an input end of the switch circuit is electrically connected with the power supply, and an output end of the switch circuit is electrically connected with a load; when the first detection circuit detects that a first power supply signal provided by the power supply is normal, the first detection circuit controls the switch circuit to be turned on, so that the first power supply signal is provided to the load; and the first detection circuit is further used for controlling the switch circuit to be turned off when the first detection circuit detects that the first power supply signal provided by the power supply is abnormal. In the embodiment of the present application, when the first power supply signal appears transient peak value, abnormal value or surge, the first detection circuit controls the switch circuit to be turned off; when the first power supply signal is within a reasonable signal range, the first detection circuit controls the switch circuit to be turned on; and the load damage caused by the abnormal problem of the first power supply signal is avoided, so that the protection of the load is realized.

Description

Technical Field

[0001] This invention relates to the field of power grid technology, and more particularly to a protection device. Background Technology

[0002] Currently, most ordinary households are connected to the 220V municipal power grid. The input current for household appliances in residential homes is 220V AC.

[0003] However, in some areas, the mains power supply may experience poor input current quality, such as instantaneous peak values ​​or surges. Consequently, electrical appliances in these areas frequently suffer damage due to poor input current quality. This can range from minor damage to equipment and the power grid to serious safety accidents that endanger personal safety. Summary of the Invention

[0004] This invention provides a protection device to solve the problem of electrical equipment being damaged due to abnormal power grid conditions.

[0005] This invention provides a protection device connected between a power supply and a load, the protection device comprising: a first detection circuit and a switching circuit;

[0006] The input terminal of the first detection circuit is electrically connected to the power supply, the output terminal of the first detection circuit is electrically connected to the control terminal of the switching circuit, the input terminal of the switching circuit is electrically connected to the power supply, and the output terminal of the switching circuit is electrically connected to the load.

[0007] The first detection circuit is used to control the switching circuit to turn on when it detects that the first power supply signal provided by the power supply is normal, so that the first power supply signal is provided to the load; the first detection circuit is also used to control the switching circuit to turn off when it detects that the first power supply signal provided by the power supply is abnormal.

[0008] In this embodiment of the invention, when the first power supply signal output by the power supply experiences transient peaks, abnormal values, or surges, the first detection circuit determines that the first power supply signal provided by the power supply is abnormal. In this case, the control switch circuit is turned off, preventing the abnormal first power supply signal from entering the load, thus protecting the load and circuit safety. When the first power supply signal output by the power supply is within a reasonable signal range, the first detection circuit determines that the first power supply signal provided by the power supply is normal. In this case, the control switch circuit is turned on, allowing the normal first power supply signal provided by the power supply to enter the load, enabling the load to operate normally. This avoids damage to the load or even safety accidents caused by abnormal first power supply signals, thereby achieving protection for the load and circuit. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, although the drawings described below are some specific embodiments of the present invention, those skilled in the art can extend and extend the basic concepts of the device structure, driving method and manufacturing method disclosed and indicated by various embodiments of the present invention to other structures and drawings. Undoubtedly, these should all be within the scope of the claims of the present invention.

[0010] Figure 1 This is a schematic diagram of a protection device provided in an embodiment of the present invention;

[0011] Figure 2 This is a schematic diagram of another protection device provided in an embodiment of the present invention;

[0012] Figure 3 This is a schematic diagram of another protection device provided in an embodiment of the present invention;

[0013] Figure 4 This is a schematic diagram of another protection device provided in an embodiment of the present invention;

[0014] Figure 5 This is a schematic diagram of another protection device provided in an embodiment of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the basic concepts disclosed and indicated in the embodiments of this invention, all other embodiments obtained by those skilled in the art are within the scope of protection of this invention.

[0016] refer to Figure 1 The diagram shown is a schematic representation of a protection device provided in an embodiment of the present invention. Figure 1 As shown, the protection device 1 provided in this embodiment is connected between the power supply 2 and the load 3. The protection device 1 includes: a first detection circuit 10 and a switching circuit 20; the input terminal of the first detection circuit 10 is electrically connected to the power supply 2, the output terminal of the first detection circuit 10 is electrically connected to the control terminal of the switching circuit 20, the input terminal of the switching circuit 20 is electrically connected to the power supply 2, and the output terminal of the switching circuit 20 is electrically connected to the load 3; the first detection circuit 10 is used to control the switching circuit 20 to conduct when it detects that the first power supply signal provided by the power supply 2 is normal, so that the first power supply signal is provided to the load 3; the first detection circuit 10 is also used to control the switching circuit 20 to turn off when it detects that the first power supply signal provided by the power supply 2 is abnormal.

[0017] In this embodiment, the optional protection device 1 is a power protection device connected between the power supply 2 and the load 3. The power supply 2 can be AC ​​mains power, in which case the first power supply signal is 220V AC. In other embodiments, the power supply 2 can also be other AC or DC power, and the protection device 1 can filter out anomalies and surges in the first power supply signal. The load 3 can be any household or commercial appliance, such as an air conditioner or refrigerator in a user's home.

[0018] The protection device 1 includes a first detection circuit 10 and a switching circuit 20. The input terminal of the first detection circuit 10 is electrically connected to the power supply 2. The input terminal of the first detection circuit 10 receives a first power supply signal, detects the first power supply signal, and outputs the detection result. The output terminal of the first detection circuit 10 is electrically connected to the control terminal of the switching circuit 20. The detection result of the first detection circuit 10 controls the switching circuit 20 to turn on or off.

[0019] The input terminal of the switching circuit 20 is electrically connected to the power supply 2, and the output terminal of the switching circuit 20 is electrically connected to the load 3. When the first detection circuit 10 detects that the first power supply signal provided by the power supply 2 is normal, it controls the switching circuit 20 to conduct, so that the power supply 2 provides the normal first power supply signal to the load 3 through the switching circuit 20, enabling the load 3 to operate. When the first detection circuit 10 detects that the first power supply signal provided by the power supply 2 is abnormal, it controls the switching circuit 20 to turn off, so that the abnormal first power supply signal from the power supply 2 will not enter the load 3.

[0020] Based on this, protection device 1 can effectively and safely control the current output of power supply 2. When the output current quality of power supply 2 is poor, it blocks the transmission path between power supply 2 and load 3; when the output current of power supply 2 is within a reasonable range, it connects the transmission path between power supply 2 and load 3. This prevents damage to load 3 or even safety accidents caused by abnormal power supply signals. Thus, it protects load 3.

[0021] In this embodiment of the invention, when the first power supply signal output by the power supply experiences transient peaks, abnormal values, or surges, the first detection circuit determines that the first power supply signal provided by the power supply is abnormal. In this case, the control switch circuit is turned off, preventing the abnormal first power supply signal from entering the load, thus protecting the load and circuit safety. When the first power supply signal output by the power supply is within a reasonable signal range, the first detection circuit determines that the first power supply signal provided by the power supply is normal. In this case, the control switch circuit is turned on, allowing the normal first power supply signal provided by the power supply to enter the load, enabling the load to operate normally. This avoids damage to the load or even safety accidents caused by abnormal first power supply signals, thereby achieving load protection.

[0022] refer to Figure 2The diagram shown is a schematic representation of another protection device provided in an embodiment of the present invention. Figure 2 As shown, the optional first detection circuit 10 includes: a sampling protection module 110, a signal amplification module 120, a voltage comparison module 130, and a drive self-locking module 140 connected in sequence; the input terminal of the sampling protection module 110 is electrically connected to the power supply 2, and the output terminal of the drive self-locking module 140 is electrically connected to the control terminal of the switching circuit 20; the sampling protection module 110 is used to sample the first power supply signal of the power supply 2; the signal amplification module 120 is used to amplify the first power supply signal; the voltage comparison module 130 is used to compare the first power supply signal and a preset voltage signal and output the comparison result; the drive self-locking module 140 is used to control the switching circuit 20 to be turned on or off according to the comparison result.

[0023] In this embodiment, the input terminal of the sampling protection module 110 is electrically connected to the power supply 2, and the output terminal of the sampling protection module 110 is electrically connected to the input terminal of the signal amplification module 120, for real-time acquisition of the first power supply signal provided by the power supply 2. Regardless of whether the first power supply signal is a transient peak, an abnormal value, a surge, or a normal value, the sampling protection module 110 can acquire it.

[0024] The output terminal of the signal amplification module 120 is electrically connected to the input terminal of the voltage comparison module 130. It is used to amplify the actual first power supply signal transmitted by the sampling protection module 110. Thus, abnormal values ​​in the first power supply signal are amplified, which facilitates subsequent abnormal detection.

[0025] The output of voltage comparison module 130 is electrically connected to the input of drive self-locking module 140, and is used to compare the voltage of the amplified first power supply signal. Specifically, voltage comparison module 130 provides a preset voltage signal and compares the preset voltage signal with the first power supply signal. If the preset voltage signal is greater than or equal to the first power supply signal at the current moment, a high-level signal is output; if the preset voltage signal is less than the first power supply signal at the current moment, a low-level signal is output. Of course, depending on the preset voltage signal set in the voltage comparison module, it is also possible that if the first power supply signal at the current moment is greater than or equal to the preset voltage signal, a high-level signal is output; and if the first power supply signal at the current moment is less than the preset voltage signal, a low-level signal is output. This is not limited to this.

[0026] The output terminal of the drive self-locking module 140 is electrically connected to the control terminal of the switching circuit 20. The drive self-locking module 140 controls the switching circuit 20 to turn on or off based on the comparison result of the voltage comparison module 130.

[0027] refer to Figure 3 The diagram shown is a schematic representation of another protection device provided in an embodiment of the present invention. Figure 3As shown, the selectable protection module 110 includes: a first resistor R1, a second resistor R2, a Zener diode D1, and a first capacitor C1; the first terminal of the first resistor R1 and the first terminal of the second resistor R2 are electrically connected to the power supply 2; the second terminal of the second resistor R2, the cathode of the Zener diode D1, and the first terminal of the first capacitor C1 are respectively electrically connected to the first input terminal of the signal amplification module 120; the second terminal of the first resistor R1, the anode of the Zener diode D1, and the second terminal of the first capacitor C1 are respectively grounded to GND. Optionally, the first terminal of the first capacitor C1 can be the positive terminal, and the second terminal can be the negative terminal.

[0028] In this embodiment, the first resistor R1 can be selected with a resistance of 0.1KΩ, the second resistor R2 with a resistance of 4.7KΩ, the Zener diode D1 with a Zener voltage of 3V, and the first capacitor C1 with a capacitance of 100µF. It is understood that when the protection device is applied to different loads, the parameters of each component in the sampling protection module can be adaptively adjusted, and are not limited to this.

[0029] The optional signal amplification module 120 includes: a third resistor R3, a first feedback resistor VR1, and a first amplifier U1; the first end of the third resistor R3 is electrically connected to the non-inverting input (+) of the first amplifier U1, and the second end of the third resistor R3 is grounded to GND; the first end of the first feedback resistor VR1 is electrically connected to the non-inverting input (+) of the first amplifier U1, and the second end of the first feedback resistor VR1 is electrically connected to the output of the first amplifier U1; the inverting input (-) of the first amplifier U1 is electrically connected to the output of the sampling protection module 110, and the output of the first amplifier U1 is electrically connected to the input of the voltage comparison module 130. The second end of the second resistor R2, the cathode of the Zener diode D1, and the first terminal of the first capacitor C1 are respectively electrically connected to the inverting input (-) of the first amplifier U1.

[0030] In this embodiment, the resistance of the third resistor R3 can be 2.2KΩ, the resistance of the first feedback resistor VR1 can be 100KΩ, and the first amplifier U1 can be an LM368. It is understood that when the protection device is applied to different loads, the parameters and models of the various components in the signal amplification module can be adaptively adjusted, and are not limited to this.

[0031] When the voltage at the non-inverting input (+) of the first amplifier U1 is higher than the voltage at the inverting input (-), the first amplifier U1 outputs a high-level signal; when the voltage at the non-inverting input (+) of the first amplifier U1 is lower than the voltage at the inverting input (-), the first amplifier U1 outputs a low-level signal.

[0032] The optional voltage comparison module 130 includes: a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a second amplifier U2; the first end of the fourth resistor R4 is electrically connected to the first constant voltage terminal VCC, the second end of the fourth resistor R4 is electrically connected to the second end of the fifth resistor R5, and the first end of the fifth resistor R5 is grounded; the second ends of the fourth resistor R4 and the second ends of the fifth resistor R5 are respectively electrically connected to the non-inverting input (+) of the second amplifier U2; the first end of the sixth resistor R6 is electrically connected to the first constant voltage terminal VCC, and the second end of the sixth resistor R6 is electrically connected to the output of the second amplifier U2; the inverting input (-) of the second amplifier U2 is electrically connected to the output of the signal amplification module 120, and the output of the second amplifier U2 is electrically connected to the input of the drive self-locking module 140. The inverting input (-) of the second amplifier U2 is also electrically connected to the output of the first amplifier U1.

[0033] In this embodiment, the resistance of the fourth resistor R4 can be 22KΩ, the resistance of the fifth resistor R5 can be 4.7KΩ, the resistance of the sixth resistor R6 can be 4.7KΩ, and the second amplifier U2 can be an LM393. It is understood that when the protection device is applied to different loads, the parameters and models of the various components in the voltage comparison module can be adaptively adjusted, and are not limited to this.

[0034] When the voltage at the non-inverting input (+) of the second amplifier U2 is higher than the voltage at the inverting input (-), the output of the second amplifier U2 is a high-level signal; when the voltage at the non-inverting input (+) of the second amplifier U2 is lower than the voltage at the inverting input (-), the output of the second amplifier U2 is a low-level signal.

[0035] The optional self-locking drive module 140 includes: a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a first transistor M1, a second transistor M2, and a second diode D2. The first terminal of the seventh resistor R7 is electrically connected to the output terminal of the voltage comparison module 130, and the second terminal of the seventh resistor R7 is electrically connected to the control terminal of the first transistor M1. The first terminal of the first transistor M1 is electrically connected to the control terminal of the second transistor M2 through the eighth resistor R8, and the second terminal of the first transistor M1 is grounded (GND). The first terminal of the second transistor M2 is electrically connected to the first constant voltage terminal VCC, and the second terminal of the second transistor M2 is electrically connected to the control terminal of the first transistor M1 through the ninth resistor R9. The anode of the second diode D2 is grounded (GND), and the cathode of the second diode D2 is electrically connected to the second terminal of the second transistor M2. The second terminal of the second transistor M2 is electrically connected to the control terminal of the switching circuit 20. The first terminal of the seventh resistor R7 is also electrically connected to the output terminal of the second amplifier U2.

[0036] In this embodiment, the resistance values ​​of the seventh resistor R7, the eighth resistor R8, and the ninth resistor R9 can all be selected as 10KΩ. The first transistor M1 is a C8050, the second transistor M2 is a C8550, and the second diode D2 is an IN4007. It is understood that when the protection device is applied to different loads, the parameters and models of the various components in the self-locking drive module can be adaptively adjusted, and are not limited to this.

[0037] like Figure 3 As shown, the optional switching circuit 20 includes: a relay, the control terminal of the relay being electrically connected to the output terminal of the first detection circuit 10, the first contact k1 of the relay being electrically connected to the power supply 2, and the second contact k2 of the relay being electrically connected to the load 3; the first detection circuit 10 is used to control the first contact k1 and the second contact k2 of the relay to conduct when the first power supply signal is detected to be normal, and is also used to control the first contact k1 and the second contact k2 of the relay to turn off when the first power supply signal is detected to be abnormal.

[0038] In this embodiment, when the first detection circuit 10 detects an abnormality in the first power supply signal, such as an instantaneous peak value, the first detection circuit 10 controls the first contact k1 and the second contact k2 of the relay to open, thus cutting off the transmission path between the power supply 2 and the load 3, and the load 3 does not work.

[0039] When the first detection circuit 10 detects that the first power supply signal is normal, the first detection circuit 10 controls the first contact k1 and the second contact k2 of the relay to be turned on, and the transmission path between the power supply 2 and the load 3 is turned on, so that the power supply 2 supplies power to the load 3 to enable the load 3 to work normally.

[0040] The protection device provided in the above embodiments, when the first detection circuit detects abnormal values ​​such as instantaneous peak values ​​in the first power supply signal, controls the switching circuit to disconnect to protect the load, thereby realizing the detection of abnormal values ​​such as instantaneous peak values ​​and surges in the power supply.

[0041] refer to Figure 4 The diagram shown is a schematic representation of another protection device provided in an embodiment of the present invention. Figure 4 As shown, the optional protection device 1 further includes: a second detection circuit 30, which is connected between the output of the switching circuit 20 and the load 3; the second detection circuit 30 is used to filter the received first power supply signal and then transmit it to the load 3.

[0042] In this embodiment, the second detection circuit 30 can filter the abnormal frequency in the first power supply signal, so that the first power supply signal transmitted to the load 3 is a clean and stable electrical signal, realizing the detection of abnormal values ​​such as instantaneous peaks and surges in the power supply, as well as the detection of abnormal signals such as abnormal frequencies in the power supply.

[0043] refer to Figure 5 The diagram shown is a schematic representation of another protection device provided in an embodiment of the present invention. Figure 5 As shown, the optional second detection circuit 30 includes: a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a third transistor M3, a current mirror source 310, and a driver chip 320; the first ends of the tenth resistor R10 and the eleventh resistor R11 are electrically connected to the output terminal of the switching circuit 20, the second ends of the eleventh resistor R11 and the first ends of the twelfth resistor R12 are electrically connected to the load 3, and the second end of the tenth resistor R10 is electrically connected to the positive (+) terminal of the driver chip 320. The second terminal of the 12-resistor R12 is electrically connected to the negative terminal (-) of the driver chip 320; the control terminal of the third transistor M3 is electrically connected to the ground terminal GND of the driver chip 320, the first terminal of the third transistor M3 is electrically connected to the positive terminal (+) of the driver chip 320, and the second terminal of the third transistor M3 is electrically connected to the first terminal of the mirror current source 310; the second terminal of the mirror current source 310 is grounded to GND, the third terminal of the mirror current source 310 is grounded to GND through the 13th resistor R13, and the third terminal of the mirror current source 310 is also electrically connected to the load 3.

[0044] In this embodiment, the first terminals of the tenth resistor R10 and the eleventh resistor R11 are electrically connected to the second contact k2 of the relay. Optionally, the resistance values ​​of the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12, and the thirteenth resistor R13 can all be 1KΩ. It is understood that when the protection device is applied to different loads, the parameters and models of the various components in the second detection circuit can be adaptively adjusted, and are not limited to this.

[0045] The protection device provided in this invention can be applied between a power supply and a user device. When the electrical signal quality of the power supply is poor, the protection device can process the electrical signal provided by the power supply, disconnecting the connection between the power supply and the user device when the signal quality is poor, and reconnecting the connection when the signal quality is good. This solves the problem of easy damage to the user device caused by poor signal quality, improving electrical safety and protecting user safety.

[0046] It is understood that this protection device can be set up independently, or it can be integrated into the plug of the electrical equipment, or it can be integrated into the power supply port. There are no specific restrictions. It can effectively control the current input of the power grid to the electrical equipment, so that reasonable and safe input current enters the electrical equipment, while abnormal input current is filtered out and cannot enter the electrical equipment, thus meeting the safe power consumption requirements of the electrical equipment.

[0047] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A protective device, characterized in that, Connected between the power supply and the load, the protection device includes: a first detection circuit and a switching circuit; The input terminal of the first detection circuit is electrically connected to the power supply, the output terminal of the first detection circuit is electrically connected to the control terminal of the switching circuit, the input terminal of the switching circuit is electrically connected to the power supply, and the output terminal of the switching circuit is electrically connected to the load. The first detection circuit is used to control the switching circuit to turn on when it detects that the first power supply signal provided by the power supply is normal, so that the first power supply signal is provided to the load; the first detection circuit is also used to control the switching circuit to turn off when it detects that the first power supply signal provided by the power supply is abnormal. The protection device further includes: a second detection circuit, which is connected between the output terminal of the switching circuit and the load; the second detection circuit is used to filter the received first power supply signal before transmitting it to the load; The second detection circuit includes: a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a third transistor, a current mirror source, and a driver chip; The first end of the tenth resistor and the first end of the eleventh resistor are respectively electrically connected to the output terminal of the switching circuit. The second end of the eleventh resistor and the first end of the twelfth resistor are respectively electrically connected to the load. The second end of the tenth resistor is electrically connected to the positive terminal of the driver chip, and the second end of the twelfth resistor is electrically connected to the negative terminal of the driver chip. The positive terminal of the driver chip is electrically connected to the power supply through the tenth resistor, and the negative terminal of the driver chip is electrically connected to the load through the twelfth resistor. The control terminal of the third transistor is electrically connected to the ground terminal of the driver chip, the first terminal of the third transistor is electrically connected to the positive terminal of the driver chip, and the second terminal of the third transistor is electrically connected to the first terminal of the mirror current source. The second terminal of the mirror current source is grounded, the third terminal of the mirror current source is grounded through the thirteenth resistor, and the third terminal of the mirror current source is also electrically connected to the load.

2. The protection device according to claim 1, characterized in that, The first detection circuit includes: a sampling protection module, a signal amplification module, a voltage comparison module, and a drive self-locking module connected in sequence; The input terminal of the sampling protection module is electrically connected to the power supply, and the output terminal of the drive self-locking module is electrically connected to the control terminal of the switching circuit. The sampling protection module is used to sample the first power supply signal of the power supply. The signal amplification module is used to amplify the first power supply signal; The voltage comparison module is used to compare the first power supply signal and the preset voltage signal, and output the comparison result; The drive self-locking module is used to control the switching circuit to be turned on or off based on the comparison result.

3. The protection device according to claim 2, characterized in that, The sampling protection module includes: a first resistor, a second resistor, a Zener diode, and a first capacitor; The first end of the first resistor and the first end of the second resistor are electrically connected to the power supply. The second terminal of the second resistor, the cathode of the Zener diode, and the first terminal of the first capacitor are respectively electrically connected to the first input terminal of the signal amplification module; The second terminal of the first resistor, the positive terminal of the Zener diode, and the second terminal of the first capacitor are respectively grounded.

4. The protection device according to claim 2, characterized in that, The signal amplification module includes: a third resistor, a first feedback resistor, and a first amplifier; The first end of the third resistor is electrically connected to the non-inverting input of the first amplifier, and the second end of the third resistor is grounded. The first end of the first feedback resistor is electrically connected to the non-inverting input terminal of the first amplifier, and the second end of the first feedback resistor is electrically connected to the output terminal of the first amplifier. The inverting input terminal of the first amplifier is electrically connected to the output terminal of the sampling protection module, and the output terminal of the first amplifier is electrically connected to the input terminal of the voltage comparison module.

5. The protection device according to claim 2, characterized in that, The voltage comparison module includes: a fourth resistor, a fifth resistor, a sixth resistor, and a second amplifier; The first end of the fourth resistor is electrically connected to the first constant voltage terminal, the second end of the fourth resistor is electrically connected to the second end of the fifth resistor, and the first end of the fifth resistor is grounded. The second end of the fourth resistor and the second end of the fifth resistor are respectively electrically connected to the non-inverting input terminal of the second amplifier; The first end of the sixth resistor is electrically connected to the first constant voltage terminal, and the second end of the sixth resistor is electrically connected to the output terminal of the second amplifier. The inverting input of the second amplifier is electrically connected to the output of the signal amplification module, and the output of the second amplifier is electrically connected to the input of the drive self-locking module.

6. The protection device according to claim 2, characterized in that, The drive self-locking module includes: a seventh resistor, an eighth resistor, a ninth resistor, a first transistor, a second transistor, and a second diode; The first end of the seventh resistor is electrically connected to the output end of the voltage comparison module, and the second end of the seventh resistor is electrically connected to the control end of the first transistor. The first terminal of the first transistor is electrically connected to the control terminal of the second transistor through the eighth resistor, and the second terminal of the first transistor is grounded. The first terminal of the second transistor is electrically connected to the first constant voltage terminal, and the second terminal of the second transistor is electrically connected to the control terminal of the first transistor through the ninth resistor; The positive terminal of the second diode is grounded, and the negative terminal of the second diode is electrically connected to the second terminal of the second transistor; The second terminal of the second transistor is electrically connected to the control terminal of the switching circuit.

7. The protection device according to claim 1, characterized in that, The switching circuit includes: a relay, wherein the control terminal of the relay is electrically connected to the output terminal of the first detection circuit, the first contact of the relay is electrically connected to the power supply, and the second contact of the relay is electrically connected to the load; The first detection circuit is used to control the first contact and the second contact of the relay to conduct when the first power supply signal is detected to be normal, and is also used to control the first contact and the second contact of the relay to turn off when the first power supply signal is detected to be abnormal.

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