Detection protection circuit for direct-current residual current above 6mA and charging pile

Abstract

The utility model relates to an over 6mA direct current residual current detection protection circuit and a charging pile. The circuit comprises a leakage current detection module, a module calibration circuit, a module test circuit, a relay, a drive circuit and a single-chip microcomputer. According to the detection and protection circuit for the direct-current residual current above 6mA and the charging pile, under the condition that a B-type residual current circuit breaker which is higher in price and larger in size is not used, alternating-current residual current, pulsating direct-current residual current and smooth direct-current residual current above 6mA can be detected at the same time; the requirement of the new national standard GB / T18487-20233 for leakage current detection protection of the charging pile is met, meanwhile, the manufacturing cost and the size of the charging pile are reduced, and the reliability and the stability of the charging pile are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of leakage detection protection, and in particular to a 6mA or more DC residual current detection protection circuit and a charging pile. Background Art

[0002] In order to improve the safety of charging piles, the country has revised the charging pile standards. The new standard GB / T18487-2023 is based on the original standard GB / T18487.1-2015 "Electric Vehicle Conductive Charging System Part 1: General Requirements". It summarizes and absorbs various safety hazards that have appeared in the market in recent years, and focuses on strengthening the regulations on safety and reliability, especially in the residual current detection. More safe and reliable protection measures are proposed to further ensure the safety and reliability of the charging process.

[0003] In addition, there are some charging pile leakage protection solutions on the market that can meet the requirements of the new national standard, such as the use of type B leakage circuit breakers. However, the price of type B leakage circuit breakers is relatively high, which increases the manufacturing cost of charging piles, and type B leakage circuit breakers are large in size and are not easy to install and integrate into charging piles. Utility Model Content

[0004] In order to solve the above problems, the present invention provides a 6mA or above DC residual current detection protection circuit and a charging pile that meet the requirements of the new standard GB / T18487-2023 for charging pile leakage current detection protection and saves cost and space.

[0005] In order to achieve the above-mentioned object, in a first aspect, an embodiment of the present application provides a 6mA or more DC residual current detection protection circuit, comprising:

[0006] A leakage current detection module is provided on the charging circuit and is used to detect in real time the AC residual current, the pulsating DC residual current and the smooth DC residual current of more than 6 mA in the charging circuit; the leakage current detection module has a TRIP pin for outputting a trip signal, a CAL pin for calibrating the zero position and a TEST pin for testing the trip function;

[0007] A module calibration circuit, whose output end is connected to the CAL pin of the leakage current detection module, for calibrating the zero position of the leakage current detection module;

[0008] A module test circuit, whose output end is connected to the TEST pin of the leakage current detection module, for testing the tripping function of the leakage current detection module;

[0009] A relay, arranged in series on the charging circuit;

[0010] A driving circuit, used for driving the relay to turn on or off the charging circuit;

[0011] A single chip microcomputer, connected to the module calibration circuit, the module test circuit and the trip signal driving circuit, used to control the module calibration circuit to output a calibration signal, control the module test circuit to output a test signal, receive the trip signal output by the TRIP pin, and configured to send an alarm signal when a trip signal is detected;

[0012] Among them, the single-chip microcomputer has a level output terminal RLY_ON. When the module calibration circuit completes calibration and the module test circuit completes testing, the level output terminal RLY_ON outputs a high level signal to the drive circuit to control the relay to turn on the charging circuit; when the single-chip microcomputer detects the trip signal, the level output terminal RLY_ON outputs a low level signal to the drive circuit to control the relay to cut off the charging circuit.

[0013] A further solution is that the leakage current detection module is Goldensun TLB6-A1PC.

[0014] A further solution is to further include a slow start circuit, an output end of which is connected to the VCC pin of the leakage current detection module, and the slow start circuit is used to control the power-on timing of the leakage current detection module.

[0015] A further solution is that the slow start circuit includes a resistor R81, a resistor R82, a resistor R83, a PMOS tube Q11 and a transistor Q12, the collector of the transistor Q12 is connected to a 5V power supply through the resistor R81, the base of the transistor Q12 is connected to the resistor R82, the emitter of the transistor Q12 is grounded, and the resistor R83 is connected in parallel between the base and the emitter of the transistor Q12; the source of the PMOS tube Q11 is connected to a 5V power supply, the gate of the PMOS tube Q11 is connected to the collector of the transistor Q12, and the drain of the transistor Q12 is connected to the VCC pin of the leakage current detection module.

[0016] A further solution is that the drive circuit includes a transistor Q6, a transistor Q7, a resistor R42, a resistor R43, a resistor R45, a resistor R47 and a diode D1; the collector of the transistor Q6 is connected to a 12V power supply through a diode D1, the base of the transistor Q6 is connected to the level output terminal RLY_ON through a resistor R42, and the emitter of the transistor Q6 is grounded; the base of the transistor Q7 is connected to the TRIP pin through a resistor R45, the collector of the transistor Q7 is connected to the base of the transistor Q6, and the emitter of the transistor Q7 is grounded; the resistor R43 is connected in parallel between the collector and the emitter of the transistor Q7; one end of the resistor R47 is connected to the connection point between the base of the transistor Q7 and the resistor R45, and the other end is grounded; the control contacts of the relay are connected in parallel to the two ends of the diode D1.

[0017] A further solution is that the model of the transistor Q6 is SS8050; the model of the transistor Q7 is MMBT3904.

[0018] A further solution is that the module calibration circuit includes an NMOS tube Q8, a resistor R48, a resistor R49 and a resistor R50, the drain of the NMOS tube Q8 is connected to the drain of the transistor Q12, the source of the NMOS tube Q8 is grounded, and the gate of the NMOS tube Q8 is connected to the CAL pin through the resistor R50; the resistor R49 is connected in parallel between the gate of the NMOS tube Q8 and the source of the NMOS tube Q8.

[0019] A further solution is that the module test circuit includes an NMOS tube Q9, a resistor R51, a resistor R52 and a resistor R53, the drain of the NMOS tube Q9 is connected to the drain of the transistor Q12, the source of the NMOS tube Q9 is grounded, and the gate of the NMOS tube Q9 is connected to the TEST pin through the resistor R53; the resistor R52 is connected in parallel between the gate of the NMOS tube Q9 and the source of the NMOS tube Q9.

[0020] A further solution is that the model of the NMOS tube Q8 is CJ3400; the model of the NMOS tube Q9 is CJ3400; the model of the PMOS tube Q11 is FDN304P; and the model of the triode Q12 is MMBT3904.

[0021] In a second aspect, an embodiment of the present application provides a charging pile, characterized in that it has a DC residual current detection protection circuit of more than 6 mA as described in any embodiment of the first aspect.

[0022] The 6mA or above DC residual current detection protection circuit and charging pile designed by the present invention can simultaneously detect AC residual current, pulsating DC residual current and 6mA or above smooth DC residual current without using a more expensive and larger B-type leakage circuit breaker, meeting the requirements of the new national standard GB / T18487-20233 for charging pile leakage current detection protection, while reducing the manufacturing cost and volume of the charging pile and improving the reliability and stability of the charging pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a block diagram of a 6mA or more DC residual current detection protection circuit provided in an embodiment of the present application;

[0024] Figure 2 is a circuit diagram of a slow start circuit provided in an embodiment of the present application;

[0025] Figure 3 is a circuit diagram of a driving circuit provided in an embodiment of the present application;

[0026] Figure 4 is a circuit diagram of a module calibration circuit provided in an embodiment of the present application;

[0027] Figure 5 It is a circuit diagram of a module test circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] Example 1.

[0030] like Figure 1 As shown, in the first aspect, the embodiment of the present application provides a 6mA or more DC residual current detection protection circuit, including:

[0031] The leakage current detection module 100 is arranged on the charging circuit and is used to detect the AC residual current, the pulsating DC residual current and the smooth DC residual current of more than 6 mA in the charging circuit in real time; the leakage current detection module 100 has a TRIP pin for outputting a trip signal, a CAL pin for calibrating the zero position and a TEST pin for testing the trip function;

[0032] A module calibration circuit 101, whose output end is connected to the CAL pin of the leakage current detection module 100, for calibrating the zero position of the leakage current detection module 100;

[0033] A module test circuit 102, whose output end is connected to the TEST pin of the leakage current detection module 100, for testing the tripping function of the leakage current detection module 100;

[0034] Relay 103, arranged in series on the charging circuit;

[0035] A driving circuit 104, used for driving the relay 103 to turn on or off the charging circuit;

[0036] A single chip microcomputer 105, connected to the module calibration circuit 101, the module test circuit 102 and the trip signal driving circuit 104, used to control the module calibration circuit 101 to output a calibration signal, control the module test circuit 102 to output a test signal, receive the trip signal output by the TRIP pin, and is configured to send an alarm signal when a trip signal is detected;

[0037] Among them, the single-chip microcomputer 105 has a level output terminal RLY_ON. When the module calibration circuit 101 completes calibration and the module test circuit 102 completes testing, the level output terminal RLY_ON outputs a high level signal to the drive circuit 104 to control the relay 103 to turn on the charging circuit; when the single-chip microcomputer 105 detects the tripping signal, the level output terminal RLY_ON outputs a low level signal to the drive circuit 104 to control the relay 103 to cut off the charging circuit.

[0038] In specific implementation, the single chip microcomputer 105 can select the STM32 series single chip microcomputer as the control core of the entire protection circuit, that is, the single chip microcomputer 105 controls the module calibration circuit 101 and the module test circuit 102 to perform calibration and testing, and receives the TRIP signal of the leakage current detection module 100 and sends the RLY_ON signal to perform corresponding control and processing.

[0039] See also Figure 1 In this embodiment, the leakage current detection module 100 is a Jinshengyang TLB6-A1PC. When working, illustratively: taking the charging pile equipped with the protection as an example, the leakage current detection module 100 is arranged in series on the charging circuit. After the charging pile is powered on, the single-chip microcomputer 105 first controls the module calibration circuit 101 to perform zero-position calibration. Specifically, the single-chip microcomputer outputs a 3.3V calibration signal, and the CAL pin of the leakage current detection module 100 is pulled down through the module calibration circuit. At this time, the leakage current detection module 100 will record the current measurement value as zero position as the reference value for subsequent measurements, thereby eliminating the measurement error. For example, assuming that the leakage current detection module itself has an error of 1mA, after calibration, even if the actual leakage current is 0mA, the module will output a measurement value of 1mA. Through calibration, this error can be eliminated, so that the leakage current detection module 100 outputs a measurement value of 0mA when there is no leakage current.

[0040] Subsequently, the single-chip microcomputer 105 controls the module test circuit 102 to perform a self-test to verify whether the tripping function of the leakage current detection module 100 is normal. The single-chip microcomputer outputs a 0V self-test signal, and pulls up the TEST pin of the leakage current detection module 100 through the module test circuit to simulate the situation where the leakage current exceeds the set threshold. If the leakage current detection module 100 works normally, its TRIP pin will output a tripping signal. After the single-chip microcomputer 105 detects the TRIP signal, it is considered that the self-test has passed, indicating that the tripping function of the leakage current detection module 100 is normal. For example, assuming that the tripping threshold of the leakage current detection module 100 is 6mA, then during the self-test, the single-chip microcomputer 105 can simulate a leakage current greater than 6mA through the module test circuit 102. If the leakage current detection module 100 works normally, it will output a TRIP signal. After the single-chip microcomputer 105 receives the TRIP signal, it determines that the self-test has passed.

[0041] After the calibration and self-test are completed, the level output terminal RLY_ON of the single-chip microcomputer 105 outputs a high-level signal to the driving circuit 104. The driving circuit 104 controls the relay 103 to be turned on, so that the charging circuit is in a conductive state and charging can be performed. During the charging process, the single-chip microcomputer 105 continuously monitors the TRIP pin of the leakage current detection module 100 and keeps the RLY_ON signal at a high level, so that the relay 103 remains closed and the charging circuit remains in a conductive state.

[0042] Once the leakage current detection module 100 detects that the AC residual current, pulsating DC residual current or smooth DC residual current of more than 6mA in the charging circuit exceeds the preset threshold, its TRIP pin will output a trip signal. After receiving the TRIP signal, the drive circuit will immediately pull the RLY_ON signal down to a low level, and control the relay 103 to disconnect, cut off the charging circuit, put the charging circuit in a disconnected state, stop charging, and prevent damage caused by leakage current. At the same time, after the single-chip microcomputer 105 detects that the RLY_ON signal becomes a low level, it determines that a leakage fault has occurred and immediately sends an alarm signal to alert the user.

[0043] In this way, the circuit uses Jinshengyang TLB6-A1PC, which enables the charging pile to simultaneously detect AC residual current, pulsating DC residual current and smooth DC residual current above 6mA without using a more expensive and larger B-type leakage circuit breaker, meeting the requirements of the new standard GB / T18487-2023 for leakage current detection protection of charging piles, saving costs and space.

[0044] In some embodiments, Figure 1 As shown, a slow start circuit 107 is also included, whose output end is connected to the VCC pin of the leakage current detection module 100, and the slow start circuit 107 is used to control the power-on timing of the leakage current detection module 100. The slow start circuit 107 controls the VCC voltage to rise slowly, so that the internal components of the leakage current detection module 100 can gradually adapt to the voltage change and avoid voltage shock, thereby protecting the module and extending its service life.

[0045] Specifically, if Figure 2As shown, the slow start circuit 107 includes a resistor R81, a resistor R82, a resistor R83, a PMOS tube Q11 and a transistor Q12, the collector of the transistor Q12 is connected to a 5V power supply through the resistor R81, the base of the transistor Q12 is connected to the resistor R82, the emitter of the transistor Q12 is grounded, and the resistor R83 is connected in parallel between the base and the emitter of the transistor Q12; the source of the PMOS tube Q11 is connected to the 5V power supply, the gate of the PMOS tube Q11 is connected to the collector of the transistor Q12, and the drain of the transistor Q12 is connected to the VCC pin of the leakage current detection module 100.

[0046] When working, exemplarily: the other end of the resistor R82 is connected to the input signal Control of the external control power switch. When Control is low or high impedance, the base of the transistor Q12 is pulled down to the ground, which is low level, then the transistor Q12 is not turned on, and then the Vgs of the PMOS tube Q11 is 0, the PMOS tube Q11 is not turned on, and the drain of the transistor Q12 has no output; when the 5V power supply is just powered on, the 5V power supply can be established after the 3.3V voltage output by the LDO chip, Control is high level, the transistor Q12 is saturated and turned on, at this time the Vgs of the PMOS tube Q11 slowly increases until the PMOS tube Q11 is fully turned on, and the VCC pin voltage reaches 5V, meeting its power-on timing requirements. In this embodiment, the model of the PMOS tube Q11 is FDN304P; the model of the transistor Q12 is MMBT3904.

[0047] In some embodiments, Figure 3 As shown, the driving circuit 104 includes a transistor Q6, a transistor Q7, a resistor R42, a resistor R43, a resistor R45, a resistor R47 and a diode D1; the collector of the transistor Q6 is connected to a 12V power supply through a diode D1, the base of the transistor Q6 is connected to the level output terminal RLY_ON through a resistor R42, and the emitter of the transistor Q6 is grounded; the base of the transistor Q7 is connected to the TRIP pin through a resistor R45, the collector of the transistor Q7 is connected to the base of the transistor Q6, and the emitter of the transistor Q7 is grounded; the resistor R43 is connected in parallel between the collector and the emitter of the transistor Q7; one end of the resistor R47 is connected to the connection point between the base of the transistor Q7 and the resistor R45, and the other end is grounded; the control contacts of the relay 103 are connected in parallel to the two ends of the diode D1. In this embodiment, the model of the transistor Q6 is SS8050; the model of the transistor Q7 is MMBT3904.

[0048] In this way, when the single-chip microcomputer 105 detects that the leakage current detection module 100 has completed calibration and self-test, it will output a high-level signal to the RLY_ON pin. At this time, the transistor Q6 is turned on, and the current flows through the transistor Q6, the diode D1 and the coil of the relay 103, so that the relay 103 is attracted, the charging circuit is turned on, and normal charging begins; when the leakage current detection module 100 detects that the leakage current exceeds the preset threshold, its TRIP pin will output a high-level tripping signal. At this time, the transistor Q7 is turned on, the transistor Q6 is turned off, the relay 103 loses power and releases, the charging circuit is cut off, and charging stops; when the relay 103 is disconnected, the RLY_ON signal becomes a low level, the single-chip microcomputer 105 detects the signal change, determines that a leakage fault has occurred, and sends an alarm signal to remind the user. The drive circuit 104 is simple and reliable in design, and can effectively cooperate with the leakage current detection module 100 and the single-chip microcomputer 105 to realize the leakage protection function of the charging circuit and ensure charging safety.

[0049] In some embodiments, Figure 4 As shown, the module calibration circuit 101 includes an NMOS tube Q8, a resistor R48, a resistor R49 and a resistor R50, the drain of the NMOS tube Q8 is connected to the drain of the triode Q12, the source of the NMOS tube Q8 is grounded, and the gate of the NMOS tube Q8 is connected to the CAL pin through the resistor R50; the resistor R49 is connected in parallel between the gate of the NMOS tube Q8 and the source of the NMOS tube Q8. In this embodiment, the model of the NMOS tube Q8 is CJ3400. Through calibration, the measurement error of the leakage current detection module 100 itself can be eliminated to ensure that it can accurately measure the leakage current.

[0050] In some embodiments, Figure 5 As shown, the module test circuit 102 includes an NMOS tube Q9, a resistor R51, a resistor R52 and a resistor R53, the drain of the NMOS tube Q9 is connected to the drain of the transistor Q12, the source of the NMOS tube Q9 is grounded, and the gate of the NMOS tube Q9 is connected to the TEST pin through a resistor R53; the resistor R52 is connected in parallel between the gate of the NMOS tube Q9 and the source of the NMOS tube Q9. In this embodiment, the model of the NMOS tube Q9 is CJ3400. The module test circuit 102 can conveniently test the tripping function of the leakage current detection module by simulating the leakage current, ensuring that it can cut off the charging circuit in time when leakage occurs, and ensuring charging safety. At the same time, the circuit structure is simple and reliable, easy to control, and improves the overall reliability and safety of the charging pile.

[0051] In a second aspect, an embodiment of the present application provides a charging pile, characterized in that it has a DC residual current detection protection circuit of more than 6 mA as described in any embodiment of the first aspect.

[0052] The 6mA or above DC residual current detection protection circuit and charging pile provided in this embodiment can simultaneously detect AC residual current, pulsating DC residual current and 6mA or above smooth DC residual current without using a more expensive and larger Type B leakage circuit breaker, meeting the requirements of the new national standard GB / T18487-20233 for charging pile leakage current detection protection, while reducing the manufacturing cost and volume of the charging pile and improving the reliability and stability of the charging pile.

[0053] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0054] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A 6mA or more DC residual current detection protection circuit, characterized in that: include: A leakage current detection module is provided on the charging circuit and is used to detect in real time the AC residual current, the pulsating DC residual current and the smooth DC residual current of more than 6 mA in the charging circuit; the leakage current detection module has a TRIP pin for outputting a trip signal, a CAL pin for calibrating the zero position and a TEST pin for testing the trip function; A module calibration circuit, whose output end is connected to the CAL pin of the leakage current detection module, for calibrating the zero position of the leakage current detection module; A module test circuit, whose output end is connected to the TEST pin of the leakage current detection module, for testing the tripping function of the leakage current detection module; A relay, arranged in series on the charging circuit; A driving circuit, used for driving the relay to turn on or off the charging circuit; A single chip microcomputer, connected to the module calibration circuit, the module test circuit and the trip signal driving circuit, used to control the module calibration circuit to output a calibration signal, control the module test circuit to output a test signal, receive the trip signal output by the TRIP pin, and configured to send an alarm signal when a trip signal is detected; Among them, the single-chip microcomputer has a level output terminal RLY_ON. When the module calibration circuit completes calibration and the module test circuit completes testing, the level output terminal RLY_ON outputs a high level signal to the drive circuit to control the relay to turn on the charging circuit; when the single-chip microcomputer detects the trip signal, the level output terminal RLY_ON outputs a low level signal to the drive circuit to control the relay to cut off the charging circuit.

2. The 6mA or more DC residual current detection protection circuit according to claim 1, characterized in that: The leakage current detection module is Goldensun TLB6-A1PC.

3. The 6mA or more DC residual current detection protection circuit according to claim 2, characterized in that: It also includes a slow start circuit, whose output end is connected to the VCC pin of the leakage current detection module, and the slow start circuit is used to control the power-on timing of the leakage current detection module.

4. The 6mA or more DC residual current detection protection circuit according to claim 3, characterized in that: The slow start circuit includes a resistor R81, a resistor R82, a resistor R83, a PMOS tube Q11 and a transistor Q12, the collector of the transistor Q12 is connected to a 5V power supply through the resistor R81, the base of the transistor Q12 is connected to the resistor R82, the emitter of the transistor Q12 is grounded, and the resistor R83 is connected in parallel between the base and the emitter of the transistor Q12; the source of the PMOS tube Q11 is connected to the 5V power supply, the gate of the PMOS tube Q11 is connected to the collector of the transistor Q12, and the drain of the transistor Q12 is connected to the VCC pin of the leakage current detection module.

5. The 6 mA or more DC residual current detection protection circuit according to any one of claims 1 to 4, characterized in that: The driving circuit includes a transistor Q6, a transistor Q7, a resistor R42, a resistor R43, a resistor R45, a resistor R47 and a diode D1; the collector of the transistor Q6 is connected to a 12V power supply through a diode D1, the base of the transistor Q6 is connected to the level output terminal RLY_ON through a resistor R42, and the emitter of the transistor Q6 is grounded; the base of the transistor Q7 is connected to the TRIP pin through a resistor R45, the collector of the transistor Q7 is connected to the base of the transistor Q6, and the emitter of the transistor Q7 is grounded; the resistor R43 is connected in parallel between the collector and the emitter of the transistor Q7; one end of the resistor R47 is connected to the connection point between the base of the transistor Q7 and the resistor R45, and the other end is grounded; the control contacts of the relay are connected in parallel to the two ends of the diode D1.

6. The 6mA or more DC residual current detection protection circuit according to claim 5, characterized in that: The model of the transistor Q6 is SS8050; the model of the transistor Q7 is MMBT3904.

7. The 6mA or more DC residual current detection protection circuit according to claim 4, characterized in that: The module calibration circuit includes an NMOS tube Q8, a resistor R48, a resistor R49 and a resistor R50. The drain of the NMOS tube Q8 is connected to the drain of the transistor Q12, the source of the NMOS tube Q8 is grounded, and the gate of the NMOS tube Q8 is connected to the CAL pin through the resistor R50; the resistor R49 is connected in parallel between the gate of the NMOS tube Q8 and the source of the NMOS tube Q8.

8. The 6 mA or more DC residual current detection protection circuit according to claim 7, characterized in that: The module test circuit includes an NMOS tube Q9, a resistor R51, a resistor R52 and a resistor R53. The drain of the NMOS tube Q9 is connected to the drain of the transistor Q12, the source of the NMOS tube Q9 is grounded, and the gate of the NMOS tube Q9 is connected to the TEST pin through the resistor R53; the resistor R52 is connected in parallel between the gate of the NMOS tube Q9 and the source of the NMOS tube Q9.

9. The 6 mA or more DC residual current detection protection circuit according to claim 8, characterized in that: The model of the NMOS tube Q8 is CJ3400; the model of the NMOS tube Q9 is CJ3400; the model of the PMOS tube Q11 is FDN304P; and the model of the triode Q12 is MMBT3904.

10. A charging pile, characterized in that: A DC residual current detection protection circuit of 6 mA or more is provided.

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