Leakage protection circuit
By designing leakage protection circuits for leakage detection modules and leakage determination modules, the problem of inflexible leakage detection in the existing technology is solved, and higher power safety guarantees are achieved.
Patent Information
- Application Number
- CN202420342928.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-23
- Publication Date
- 2025-02-11
- Estimated Expiration
- 2034-02-23
AI Technical Summary
Existing leakage protection circuits are difficult to flexibly conduct leakage detection according to actual conditions, resulting in low flexibility in electricity safety guarantees.
设计了一种包括漏电检测模块和漏电判断模块的漏电保护电路，通过外部输入的触发电平信号进行漏电互感检测，判断是否输出漏电保护信号至漏电处理芯片。
It realizes flexible control of leakage detection according to actual needs, improving the flexibility of leakage protection and power safety guarantee.
Smart Images
Figure CN222464144U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of leakage protection, and in particular to a leakage protection circuit. Background Art
[0002] With the popularization of electrical equipment, electrical safety has also received widespread attention. During the use of electricity, leakage may occur. At this time, it is necessary to set up leakage protection in the corresponding equipment in advance to detect the leakage current in the electrical equipment and lines, and to deal with it in time when the current is found, so as to avoid the occurrence of dangerous accidents. At present, the leakage protection circuit mainly adopts a pure hardware method. This method is difficult to perform leakage detection when leakage self-test is required according to the actual situation. Usually, leakage detection is performed once every period of time, which has low flexibility and is difficult to ensure the safety of electricity use for users of electrical equipment.
[0003] Therefore, how to improve the flexibility of leakage protection and ensure the safety of users' electricity use is a technical problem that needs to be solved urgently. Utility Model Content
[0004] The embodiment of the present application provides a leakage protection circuit, which can achieve the beneficial effect of improving the flexibility of leakage protection and ensuring the safety of users' electricity use.
[0005] The present application provides a leakage protection circuit: a leakage protection circuit, comprising a leakage detection module and a leakage judgment module;
[0006] The leakage detection module is used to perform leakage mutual inductance detection according to an externally input trigger level signal to obtain a judgment level signal;
[0007] The leakage judgment module is used to determine whether to output a leakage protection signal to an external leakage processing chip according to the judgment level signal, so as to implement leakage protection in the case of leakage.
[0008] By adopting the above technical solution, a trigger level signal can be issued according to the actual leakage detection needs. After being issued, the leakage detection module will perform leakage mutual inductance detection to determine whether there is a leakage phenomenon. If there is a leakage phenomenon, a high-level leakage protection signal will be sent to the device used to handle the leakage situation, thereby realizing flexible control of leakage detection according to actual needs.
[0009] Optionally, the leakage detection module includes a self-detection trigger unit and a leakage mutual inductance unit;
[0010] The self-test trigger unit is used to control the primary side of the leakage mutual inductance unit to generate a first current after receiving the trigger level signal;
[0011] The leakage mutual inductance unit is used to generate a second current on the secondary side of the leakage mutual inductance unit through mutual inductance after generating the first current, and send the judgment level signal to the leakage judgment module according to the current difference between the first current and the second current.
[0012] By adopting the above technical solution, if no leakage occurs, the current difference between the first current and the second current should be within the preset range. At this time, a low level is output to the leakage judgment module and the power supply operates normally; if leakage occurs, the current difference is greater than the preset range. At this time, a high level is output to the leakage judgment module, and the leakage judgment module outputs a corresponding control signal to handle the leakage.
[0013] Optionally, the self-test trigger unit includes a first resistor, a second resistor, a third resistor and a first transistor;
[0014] One end of the first resistor receives the trigger level signal, and the other end is connected to the base of the first transistor, the emitter of the first transistor is grounded, the collector of the first transistor is connected to one end of the second resistor, and the other end of the second resistor is connected to an external first DC signal source;
[0015] One end of the third resistor is connected to a connection point between the first resistor and the first transistor, and the other end of the third resistor is grounded.
[0016] By adopting the above technical solution, the first transistor receives an external trigger level signal, and triggers the leakage mutual inductance after receiving the signal, thereby realizing flexible control of leakage detection.
[0017] Optionally, the leakage mutual inductance unit includes a leakage mutual inductor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a first capacitor;
[0018] The leakage transformer comprises a main coil and a secondary coil, one end of the main coil is connected to the first DC signal source, and the other end is connected to one end of the second resistor;
[0019] One end of the secondary coil is connected to one end of the fourth resistor, one end of the fifth resistor, one end of the sixth resistor and one end of the first capacitor;
[0020] The other end of the sixth resistor is connected to the first input end of the leakage judgment module;
[0021] The other end of the secondary coil is connected to the other end of the fourth resistor, the other end of the fifth resistor, one end of the seventh resistor and the other end of the first capacitor;
[0022] The other end of the seventh resistor is connected to the second input end of the leakage judgment module.
[0023] By adopting the above technical solution, when the current in the main coil of the leakage transformer changes, since the current vector sum of the two wires passing through is zero, the secondary coil will generate an induced electromotive force accordingly when leakage occurs in the wire, thereby adjusting the subsequent signal output to the leakage judgment module.
[0024] Optionally, the leakage judgment module includes a differential amplifier;
[0025] The non-inverting input terminal of the differential amplifier is connected to the other end of the sixth resistor, and the inverting input terminal of the differential amplifier is connected to the other end of the seventh resistor;
[0026] The output end of the differential amplifier is connected to the leakage processing chip.
[0027] By adopting the above technical solution, the differential amplifier can output a high level to the subsequent leakage processing chip based on the differential mode signal in the output signal of the above leakage transformer when a current imbalance caused by leakage occurs. The leakage processing chip will perform corresponding leakage processing when receiving this high level.
[0028] Optionally, the leakage judgment module further includes a second capacitor and an eighth resistor;
[0029] One end of the second capacitor is connected to the connection point between the seventh resistor and the differential amplifier, and the other end of the second capacitor is connected to an external second DC signal source;
[0030] The eighth resistor is connected in parallel to both ends of the second capacitor.
[0031] By adopting the above technical solution, a stable operating point is provided for the differential amplifier, so that the output signal is generated when the input signal changes, rather than being offset due to power supply or other factors. At the same time, the capacitor can suppress the high-frequency noise of DC bias, thereby ensuring DC stability.
[0032] Optionally, the leakage judgment module further includes a ninth resistor and a third capacitor;
[0033] The ninth resistor is connected in series between the differential amplifier and the leakage processing chip;
[0034] One end of the third capacitor is connected to a connection point between the ninth resistor and the leakage processing chip, and the other end of the third capacitor is grounded.
[0035] By adopting the above technical solution, the ninth resistor is used for voltage division to prevent the instantaneous electrical signal of the leakage processing chip from being too large, and then the third capacitor is grounded to filter the interference signal to ensure the stability of the signal, so as to improve the leakage processing chip to accurately receive the signal.
[0036] Optionally, the leakage judgment module further includes a tenth resistor and a fourth capacitor;
[0037] One end of the tenth resistor is connected to the non-inverting input terminal of the differential amplifier, and the other end is connected to the output terminal of the differential amplifier;
[0038] One end of the fourth capacitor is connected to one end of the tenth resistor, and the other end of the fourth capacitor is connected to the other end of the tenth resistor.
[0039] By adopting the above technical solution, feedback regulation is formed to ensure the stability of the circuit, so that the differential amplifier can provide stable and accurate output, thereby preventing the leakage processing chip from misjudging the leakage situation due to the unstable output signal of the differential amplifier.
[0040] In summary, the present application includes at least one of the following beneficial effects:
[0041] 1. The trigger level signal can be issued according to the actual leakage detection needs. After being issued, the leakage mutual inductance detection will be performed through the leakage detection module. If no leakage occurs, the current difference between the first current and the second current should be within the preset range. At this time, a low level is output to the leakage judgment module, and the power is normally operated; if a leakage occurs, the current difference is greater than the preset range. At this time, a high level is output to the leakage judgment module. The leakage judgment module outputs a corresponding control signal to process the leakage to determine whether there is a leakage phenomenon. If there is a leakage phenomenon, a high-level leakage protection signal is sent to the device used to process the leakage situation, thereby realizing flexible control of leakage detection according to actual needs.
[0042] 2. This circuit uses fewer circuit components and has low circuit complexity, thereby effectively reducing the circuit cost of leakage protection.
[0043] 3. This application uses a differential amplifier for signal amplification and leakage judgment. Due to the characteristics of the differential amplifier, the output signal will not be interfered by the common-mode signal, thereby improving the stability of the output signal. BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Figure 1 It is a module connection diagram of the leakage protection circuit provided in the embodiment of the present application;
[0045] Figure 2 It is a circuit schematic diagram of the leakage protection circuit provided in the embodiment of the present application. DETAILED DESCRIPTION
[0046] The following examples will help those skilled in the art to further understand the effects of the present application, but are not intended to limit the present application in any form. It should be noted that, for those of ordinary skill in the art, several modifications and improvements may be made without departing from the concept of the present application. These all fall within the scope of protection of the present application.
[0047] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.
[0048] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.
[0049] It should also be understood that the term “and / or” used in the specification and appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
[0050] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.
[0051] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.
[0052] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.
[0053] The present application is further described in detail below in conjunction with the accompanying drawings.
[0054] Reference Figure 1 , Figure 1 : is a module connection diagram of the leakage protection circuit provided in the embodiment of the present application. The circuit includes a leakage detection module and a leakage judgment module. The leakage detection module and the leakage judgment module are described in detail below:
[0055] The leakage detection module 1 is used to perform the leakage mutual inductance detection according to the external input trigger level signal to obtain a judgment level signal.
[0056] About the leakage detection module 1: The leakage detection module 1 provided in the present application is triggered by an external control device. For example, the external control device can be a PC, a single-chip microcomputer, or a device with buttons. Through the control device, the leakage transformer contained in the leakage detection module can be controlled to start working. Among them, the control device can be controlled by a pre-set logic control program. When the circuit to be detected (hereinafter referred to as the circuit to be tested) starts to be powered on, or when leakage detection is required according to actual conditions, the control device will send a trigger level signal to start leakage detection.
[0057] Specifically, the leakage detection module 1 includes a self-detection trigger unit 11 and a leakage mutual inductance unit 12 .
[0058] The self-test trigger unit 11 is used to control the primary side of the leakage mutual inductance unit to generate a first current after receiving the trigger level signal.
[0059] Regarding the self-test trigger unit 11: the self-test trigger module should include at least one switching tube for controlling the conduction of the circuit. In the present application, a transistor is used for control. When an external control device sends a trigger level signal to the base of the transistor, thereby opening the path between the collector of the transistor and the emitter of the transistor, after the path is turned on, a current is generated in the coil arranged on the primary side of the leakage mutual inductance unit, that is, a first current. After the first current is generated, a second current will be generated correspondingly on the secondary side of the leakage mutual inductance unit. This part is specifically described in the description of the leakage mutual inductance unit.
[0060] The leakage mutual inductance unit 12 is used to generate a second current on the secondary side of the leakage mutual inductance unit 12 through mutual inductance after generating the first current, and send the judgment level signal to the leakage judgment module according to the current difference between the first current and the second current.
[0061] About the leakage mutual inductance unit 12: The leakage mutual inductance unit 12 contains at least one leakage mutual inductor, the primary side of the leakage mutual inductance is wound with a primary coil, and the secondary side is wound with a secondary coil. When the first current flows through the primary coil, the secondary coil will generate an induced electromotive force, that is, generate a second current. In this application, the live wire and the neutral wire of the circuit to be tested pass through the leakage mutual inductance unit. Before there is no leakage, the current vector sum of the live wire and the neutral wire should be 0, that is, the currents are equal in magnitude and opposite in direction.
[0062] Specifically, since the leakage transformer relies on the principle of electromagnetic induction to realize leakage fault detection, the two wires of the same circuit (usually the live wire and the neutral wire) pass through the leakage transformer. Since the currents on each wire are equal but opposite, their vector sum is 0. When leakage occurs in the line, that is, the wires below the leakage transformer have branches, the vector sum of the current passing through the leakage transformer is no longer 0, and the secondary stage of the transformer will generate an induced potential. Based on whether the induced electromotive force is generated, it can be determined whether leakage occurs.
[0063] The leakage judgment module 2 is used to determine whether to output a leakage protection signal to an external leakage processing chip according to the judgment level signal, so as to implement leakage protection in the case of leakage.
[0064] About the leakage judgment module 2: The leakage judgment module 2 includes at least one stage of amplification circuit. In a possible embodiment, it can be composed of a multi-stage amplification circuit, which is triggered by the judgment level signal output by the above-mentioned leakage detection module, and finally outputs a leakage protection signal to the corresponding leakage processing chip. Among them, the leakage protection signal can be a high-level signal, and the leakage processing chip can be a single-chip microcomputer that controls the on and off of the circuit to be tested. In the embodiment provided in the present application, the multi-stage amplification circuit can be replaced by a first-stage differential amplifier. After receiving the leakage judgment level, if it is a leakage state, a high level is output to the corresponding leakage processing chip. The leakage processing chip can disconnect the leakage circuit accordingly, and further issue a leakage alarm.
[0065] Furthermore, since the present application uses a differential amplifier for amplification, the differential amplifier can amplify the difference between two signals due to its characteristics. In this difference-making process, the common-mode signal is the common part relative to the same reference point, thereby realizing the circuit's suppression of common-mode interference.
[0066] The following is a possible circuit connection method for further explanation. Figure 2 , Figure 2 This is the circuit schematic diagram of the leakage protection circuit provided by this application. The device description is specifically described below:
[0067] The self-test trigger unit 11 includes a first resistor R1, a second resistor R2, a third resistor R3 and a first transistor Q1;
[0068] One end of the first resistor R1 receives the trigger level signal, and the other end is connected to the base of the first transistor Q1, the emitter of the first transistor Q1 is grounded, the collector of the first transistor Q1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is connected to an external first DC signal source VCC1;
[0069] One end of the third resistor R3 is connected to a connection point between the first resistor R1 and the first transistor Q1 , and the other end of the third resistor R3 is grounded.
[0070] Specifically, when the external control device sends a trigger level signal to the base of Q1, the collector and emitter of Q1 will be turned on, and VCC1 will pass through R2 and Q1 to the ground. In this process, the signal flows through the primary coil of the leakage transformer CT1 described below. In addition, resistor R1 is used for voltage division, and R3 is used for voltage discharge, so that the signal is discharged to the ground through R3 when Q1 is not turned on.
[0071] The leakage mutual inductance unit includes a leakage mutual inductor CT1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a first capacitor C1;
[0072] The leakage transformer CT1 includes a main coil and a secondary coil, one end of the main coil is connected to the first DC signal source VCC1, and the other end is connected to one end of the second resistor R2;
[0073] One end of the secondary coil is connected to one end of the fourth resistor R4, one end of the fifth resistor R5, one end of the sixth resistor R6 and one end of the first capacitor C1;
[0074] The other end of the sixth resistor R6 is connected to the first input end of the leakage judgment module 2;
[0075] The other end of the secondary coil is connected to the other end of the fourth resistor R4, the other end of the fifth resistor R5, one end of the seventh resistor R7 and the other end of the first capacitor C1;
[0076] The other end of the seventh resistor R7 is connected to the second input end of the leakage judgment module 2 .
[0077] Specifically, CT1 should be a hollow device. In the embodiment of the present application, a ring is used as an example. The neutral line and the live line in the same loop of the circuit to be tested pass through CT1. When the above-mentioned self-test trigger unit 11 receives the trigger level signal, a current, namely the first current, will be generated in the main coil. However, since the neutral line and the live line should be electrical signals of similar magnitude and opposite directions, according to the principle of electromagnetic induction, the generated induced electromotive force is offset. Based on this principle, when leakage occurs in the loop, there will be a certain deviation in the magnitude of the electrical signals in the neutral line and the live line, that is, the vector sum is no longer close to 0, and the secondary coil will generate an induced electromotive force, which will be converted into a leakage judgment signal to the leakage judgment module 2.
[0078] The leakage judgment module 2 includes a differential amplifier U1;
[0079] The non-inverting input terminal of the differential amplifier U1 is connected to the other end of the sixth resistor R6, and the inverting input terminal of the differential amplifier is connected to the other end of the seventh resistor R7;
[0080] The output end of the differential amplifier U1 is connected to the leakage processing chip.
[0081] Specifically, the differential amplifier U1 will output a high-level signal to the leakage processing chip according to the voltage difference between the positive input terminal and the negative input terminal. In order to avoid misjudgment, the current trigger sensitivity can be set, that is, the first current is adjusted as the preset protection current. When the difference between the positive input terminal and the negative input terminal is greater than the preset protection current (in this embodiment, the preset protection current is 30mA), a high level will be output through the differential amplifier U1, that is, a leakage protection signal is sent to the external leakage processing chip, wherein the leakage processing chip can be an MCU, and the MCU can control the on and off of the measured circuit according to the leakage situation.
[0082] Furthermore, the leakage judgment module 2 also includes a second capacitor C2 and an eighth resistor R8;
[0083] One end of the second capacitor C2 is connected to the connection point between the seventh resistor R7 and the differential amplifier U1, and the other end of the second capacitor C2 is connected to an external second DC signal source VCC2;
[0084] The eighth resistor R8 is connected in parallel to both ends of the second capacitor C2.
[0085] Specifically, VCC2 can provide a stable operating point for U1 to improve the stability of the differential amplifier. Furthermore, when leakage occurs, after the differential amplifier U1 outputs a high level, it is also necessary to send a signal to the leakage processing chip at the back end to prevent the instantaneous excessive signal change from damaging the back-end equipment. At the same time, the signal stability should be improved to avoid affecting the normal operation of the loop. The following is a specific explanation:
[0086] The leakage judgment module 2 also includes a ninth resistor R9 and a third capacitor C3;
[0087] The ninth resistor R9 is connected in series between the differential amplifier U1 and the leakage processing chip;
[0088] One end of the third capacitor C3 is connected to the connection point between the ninth resistor R9 and the leakage processing chip, and the other end of the third capacitor C3 is grounded.
[0089] Specifically, R9 is used for voltage division protection, and C3 is used for filtering the signal output to the leakage processing chip to improve the reliability of the signal.
[0090] In addition, in order to improve the stability of U1, this embodiment also adds negative feedback, which is described in detail below:
[0091] The leakage judgment module 2 also includes a tenth resistor and a fourth capacitor;
[0092] One end of the tenth resistor R10 is connected to the non-inverting input end of the differential amplifier U1, and the other end is connected to the output end of the differential amplifier U1;
[0093] One end of the fourth capacitor C4 is connected to one end of the tenth resistor R10 , and the other end of the fourth capacitor C4 is connected to the other end of the tenth resistor R10 .
[0094] Specifically, the feedback adjustment stabilizes the static operating point to prevent non-ideal factors such as power supply fluctuations and temperature changes from affecting the static operating point of the circuit, thereby affecting performance. This embodiment uses a variety of designs to ensure signal stability to avoid misjudgment of leakage devices, thereby improving the reliability of leakage detection.
[0095] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.
[0096] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.
[0097] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.
Claims
1. A leakage protection circuit, characterized in that: It includes a leakage detection module and a leakage judgment module; The leakage detection module is used to perform leakage mutual inductance detection according to an externally input trigger level signal to obtain a judgment level signal; The leakage judgment module is used to determine whether to output a leakage protection signal to an external leakage processing chip according to the judgment level signal, so as to implement leakage protection in the case of leakage.
2. The leakage protection circuit according to claim 1, characterized in that: The leakage detection module includes a self-test trigger unit and a leakage mutual inductance unit; The self-test trigger unit is used to control the primary side of the leakage mutual inductance unit to generate a first current after receiving the trigger level signal; The leakage mutual inductance unit is used to generate a second current on the secondary side of the leakage mutual inductance unit through mutual inductance after generating the first current, and send the judgment level signal to the leakage judgment module according to the current difference between the first current and the second current.
3. The leakage protection circuit according to claim 2, characterized in that: The self-test trigger unit includes a first resistor, a second resistor, a third resistor and a first triode; One end of the first resistor receives the trigger level signal, and the other end is connected to the base of the first transistor, the emitter of the first transistor is grounded, the collector of the first transistor is connected to one end of the second resistor, and the other end of the second resistor is connected to an external first DC signal source; One end of the third resistor is connected to a connection point between the first resistor and the first transistor, and the other end of the third resistor is grounded.
4. The leakage protection circuit according to claim 3, characterized in that: The leakage mutual inductance unit comprises a leakage mutual inductor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a first capacitor; The leakage transformer comprises a main coil and a secondary coil, one end of the main coil is connected to the first DC signal source, and the other end is connected to one end of the second resistor; One end of the secondary coil is connected to one end of the fourth resistor, one end of the fifth resistor, one end of the sixth resistor and one end of the first capacitor; The other end of the sixth resistor is connected to the first input end of the leakage judgment module; The other end of the secondary coil is connected to the other end of the fourth resistor, the other end of the fifth resistor, one end of the seventh resistor and the other end of the first capacitor; The other end of the seventh resistor is connected to the second input end of the leakage judgment module.
5. The leakage protection circuit according to claim 4, characterized in that: The leakage judgment module includes a differential amplifier; The non-inverting input terminal of the differential amplifier is connected to the other end of the sixth resistor, and the inverting input terminal of the differential amplifier is connected to the other end of the seventh resistor; The output end of the differential amplifier is connected to the leakage processing chip.
6. The leakage protection circuit according to claim 5, characterized in that: The leakage judgment module also includes a second capacitor and an eighth resistor; One end of the second capacitor is connected to the connection point between the seventh resistor and the differential amplifier, and the other end of the second capacitor is connected to an external second DC signal source; The eighth resistor is connected in parallel to both ends of the second capacitor.
7. The leakage protection circuit according to claim 6, characterized in that: The leakage judgment module also includes a ninth resistor and a third capacitor; The ninth resistor is connected in series between the differential amplifier and the leakage processing chip; One end of the third capacitor is connected to a connection point between the ninth resistor and the leakage processing chip, and the other end of the third capacitor is grounded.
8. The leakage protection circuit according to claim 6, characterized in that: The leakage judgment module also includes a tenth resistor and a fourth capacitor; One end of the tenth resistor is connected to the non-inverting input terminal of the differential amplifier, and the other end is connected to the output terminal of the differential amplifier; One end of the fourth capacitor is connected to one end of the tenth resistor, and the other end of the fourth capacitor is connected to the other end of the tenth resistor.