Relay adhesion detection circuit for high-voltage loop and battery management system

Abstract

The utility model discloses a relay adhesion detection circuit for a high-voltage loop, and the circuit comprises a sampling circuit which is used for collecting the voltage of the rear end of a relay at the negative electrode side of a high-voltage power supply, and is connected with a multiplexing module; the constant current control module is connected with the sampling circuit and is used for providing stable current when the circuit works; the multiplexing module comprises at least one multiplexer chip, and the multiplexer chip comprises a plurality of signal input ends, a signal output end and a selection end; the plurality of signal input ends are connected to the voltage output end of the sampling circuit, the selection end is used for selecting one input signal in the plurality of signal input ends to output to the signal output end, and the signal output end is used for outputting the signal input by the signal input end so as to judge whether the high-voltage power supply cathode side relay is adhered or not. According to the utility model, more voltage detection IO port channels can be expanded, and hardware simulation IO port resources of the micro-control unit are effectively saved. The utility model also provides a battery management system.

Description

Technical Field

[0001] The utility model relates to the technical field of electronics, and in particular to a relay adhesion detection circuit and a battery management system for a high-voltage circuit. Background Art

[0002] The battery system (referring to the power source of electric vehicles) is a core component of electric vehicles. Electric vehicles integrate numerous electronic modules. To meet the increasing high-voltage requirements of fast charging, real-time voltage monitoring of the negative-side high-voltage relay is required to detect the high-voltage operating status and, in turn, determine the relay's sticking status.

[0003] There are many existing methods for diagnosing and detecting adhesion of the main negative high-voltage relay. Most of them directly output the detected voltage to the microcontroller unit for processing and judgment. However, the IO port resources of the microcontroller unit are limited. If a large number of relays need to be detected, a large amount of hardware analog IO port resources of the microcontroller unit will be consumed, resulting in a certain degree of waste of hardware resources. Utility Model Content

[0004] The purpose of this utility model is to solve the problem of wasted analog IO port resources in the microcontroller unit hardware in existing relay sticking detection circuits. This utility model provides a relay sticking detection circuit and battery management system for high-voltage circuits. This circuit not only expands the existing multiple relay sticking detection IO port channels, but also effectively saves analog IO port resources in the microcontroller unit hardware, thereby improving the flexibility of relay sticking detection.

[0005] To solve the above technical problems, the embodiment of the present utility model discloses a relay adhesion detection circuit for a high-voltage circuit, wherein the high-voltage circuit includes a high-voltage power supply, a total positive relay, a pre-charge relay, a pre-charge resistor, a fast-charge positive relay, a negative-side relay of the high-voltage power supply, and a load. The detection circuit includes: a constant current control module, a sampling circuit, and a multiplexing module; wherein,

[0006] The sampling circuit is used to collect the voltage at the rear end of the negative-side relay of the high-voltage power supply and connect to the multiplexing module;

[0007] The constant current control module is connected to the sampling circuit to provide a stable current when the circuit is working;

[0008] The multiplexing module includes at least one multiplexer chip for expanding multiple detection IO port channels; wherein the multiplexer chip includes multiple signal input terminals, signal output terminals and a selection terminal; the multiple signal input terminals are connected to the voltage output terminal of the sampling circuit, the selection terminal is used to select an input signal from the multiple signal input terminals and output it to the signal output terminal, and the signal output terminal is used to output the signal input from the signal input terminal to determine whether the negative side relay of the high-voltage power supply is stuck.

[0009] Using this technical solution, a detection circuit consisting of a sampling circuit and a constant current control module can be designed to collect the voltage at the rear end of the negative-side relay of the high-voltage power supply. A multiplexer chip can be added to the multiplexing module to receive and output the collected voltage signal. By providing this multiplexer chip, a selection terminal can select one of the multiple voltage acquisition signals for output processing, eliminating the need to connect all of the multiple voltage acquisition signal output terminals to the signal processing unit. This allows for the detection of multiple relay adhesion states while conserving hardware analog IO port resources in the signal processing unit.

[0010] According to another specific embodiment of the present invention, the embodiment of the present invention discloses a sampling circuit including a high-voltage sampling circuit and a low-voltage control module, and the low-voltage control module is used to control the high-voltage sampling circuit to collect the voltage at the rear end of the negative side relay of the high-voltage power supply.

[0011] According to another specific embodiment of the present invention, the embodiment of the present invention discloses a relay adhesion detection circuit for a high-voltage circuit, which also includes a microcontroller unit, connected to a low-voltage control module, and receives a signal output from a signal output end of the multiplexing module, for determining whether the negative side relay of the high-voltage power supply is adhered.

[0012] According to another specific embodiment of the present utility model, the embodiment of the present utility model discloses a low voltage control module including an NPN transistor and a current limiting resistor;

[0013] The collector of the NPN transistor is connected to the high-voltage sampling circuit through a current-limiting resistor, the base of the NPN transistor is connected to the micro control unit to receive the control signal of the micro control unit, and the emitter of the NPN transistor is connected to the negative electrode of the high-voltage power supply.

[0014] According to another specific embodiment of the present utility model, an embodiment of the present utility model discloses a constant current control module including a first resistor, a second diode and a third diode;

[0015] One end of the first resistor is connected to the first power supply, and the other end is connected to the high-voltage sampling circuit;

[0016] The anode of the third diode is connected to one end of the first resistor, and the cathode is connected to the anode of the second diode; the cathode of the second diode is connected between the current limiting resistor and the high-voltage sampling circuit.

[0017] According to another specific embodiment of the present utility model, an embodiment of the present utility model discloses a high-voltage sampling circuit including a PNP transistor and a first diode;

[0018] The base of the PNP transistor is connected to one end of the current limiting resistor, the collector of the PNP transistor is connected to the other end of the first resistor, the emitter of the PNP transistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the negative side of the high-voltage power supply through the detection line. The end of the relay is away from the negative pole of the high-voltage power supply.

[0019] According to another specific embodiment of the present invention, the embodiment of the present invention discloses a relay adhesion detection circuit for a high-voltage circuit, further comprising a filter circuit module for filtering out external interference, the filter circuit module comprising a second resistor and a first capacitor;

[0020] One end of the second resistor is connected to the base of the PNP transistor, and the other end is connected to the signal input terminal of the multiplexer chip;

[0021] One end of the capacitor is connected to the other end of the resistor, and the other end is connected to the negative electrode of the high voltage power supply.

[0022] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a multiplexer chip further including a positive power pin, a negative power pin, a ground pin and a filter capacitor, the positive power pin is connected to the second power supply, the negative power pin is connected to the negative electrode of the high-voltage power supply, and the filter capacitor is connected between the second power supply and the negative electrode of the high-voltage power supply.

[0023] According to another specific embodiment of the present invention, the embodiment of the present invention discloses that the negative side relay of the high voltage power supply is a total negative relay or a fast charging negative relay.

[0024] According to another specific embodiment of the present invention, the embodiment of the present invention discloses that both the first power supply and the second power supply are 5V DC voltage.

[0025] An embodiment of the present utility model further discloses a battery management system, comprising the relay adhesion detection circuit for a high-voltage circuit mentioned in any of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A block diagram of a relay adhesion detection circuit for a high-voltage circuit provided by a specific embodiment of the present utility model is shown;

[0027] Figure 2 A block diagram of a relay adhesion detection circuit for a high-voltage circuit provided by another specific embodiment of the present utility model is shown;

[0028] Figure 3 A circuit diagram of a relay adhesion detection circuit for a high-voltage circuit provided by a specific embodiment of the present utility model is shown. DETAILED DESCRIPTION

[0029] The following is an explanation of the implementation of the present invention by means of specific specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this utility model are limited to this implementation. On the contrary, the purpose of introducing the utility model in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide an in-depth understanding of the present invention, the following description will contain many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0030] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0031] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on the utility model.

[0032] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0033] In the description of this embodiment, it should be noted that, unless otherwise specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this embodiment based on the specific circumstances.

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0035] One embodiment of the present invention provides a relay adhesion detection circuit for a high voltage circuit, referring to Figure 1 and Figure 2 The high-voltage circuit 101 includes a high-voltage power supply BAT, a main positive relay K1, a pre-charge relay K2, a pre-charge resistor R1, a fast-charge positive relay K4, a negative-side relay of the high-voltage power supply and a load (not shown in the figure). The detection circuit includes: a constant current control module 104, a sampling circuit and a multiplexing module 103.

[0036] The sampling circuit is used to collect the voltage at the rear end of the negative-side relay of the high-voltage power supply and is connected to the multiplexing module 103;

[0037] The constant current control module 104 is connected to the sampling circuit and is used to provide a stable current when the circuit is working;

[0038] According to an embodiment of the present application, the multiplexing module 103 includes at least one multiplexer chip UH2 for expanding the multi-channel detection IO port channel; wherein the multiplexer chip UH2 includes a plurality of signal input terminals (such as Figure 3 CSN0, CSN1, CSN2, CSN3, CSN4, CSN5, CSN6, CSN7), signal output terminals (such as Figure 3 IPRVAL) and selection terminal (as shown Figure 3 MXSLA, MXSLB, MXSLC shown); multiple signal input terminals are connected to the voltage output terminal of the sampling circuit, the selection terminal is used to select one of the multiple signal input terminals to output an input signal to the signal output terminal, and the signal output terminal is used to output the signal input from the signal input terminal to determine whether the negative side relay of the high-voltage power supply is stuck.

[0039] To address the issues encountered in existing relay sticking detection, the present invention utilizes a detection circuit comprising a sampling circuit and a constant current control module 104 to collect the voltage at the rear end of the negative-side relay of a high-voltage power supply. Multiplexer chip UH2 is then added to multiplexing module 103 to receive and output the collected voltage signal. By providing multiplexer chip UH2, a selection terminal can select one of multiple voltage sampling signals for output processing, eliminating the need to connect all of the multiple voltage sampling signal output terminals to the signal processing unit. This allows for the detection of multiple relay sticking states while conserving the hardware analog IO port resources of the signal processing unit.

[0040] Furthermore, a relay adhesion detection circuit for a high-voltage circuit also includes a microcontroller unit 106, which is connected to the low-voltage control module 105 and receives a signal output from the signal output end of the multiplexing module 103, for determining whether the negative side relay of the high-voltage power supply is adhered.

[0041] In some embodiments, the negative-side relay of the high-voltage power supply may be a total negative relay K3 or a fast-charge negative relay K5.

[0042] During specific implementation, the micro-control unit can control the conduction or disconnection of multiple relay adhesion detection circuits. When it is necessary to detect the adhesion of the total negative relay K3, the micro-control unit pin corresponding to the total negative relay K3 adhesion detection circuit can be made to output a high level. At this time, the adhesion detection circuit connected to the back end of the total negative relay K3 can be turned on and control the sampling circuit to collect voltage; when it is necessary to detect the adhesion of the fast-charge relay K5, the micro-control unit pin corresponding to the adhesion detection circuit of the fast-charge negative relay K5 can be made to output a high level. At this time, the adhesion detection circuit connected to the back end of the fast-charge negative relay K5 can be turned on and control the sampling circuit to collect voltage. Those skilled in the art will understand that the conduction control condition of the relay adhesion detection circuit can also be opposite to the present embodiment. For example, the micro-control unit outputs a high level, controls the relay adhesion detection circuit to disconnect, and the micro-control unit outputs a low level, controls the relay adhesion detection circuit to be turned on. Similarly, those skilled in the art will understand that the microcontroller unit may also be composed of other circuit elements or conventional circuit structures, such as a single-chip microcomputer, which may output high and low level trigger signals to control the on and off of the relay adhesion detection circuit.

[0043] According to an embodiment of the present application, a microcontroller unit 106, which is provided in a relay sticking detection circuit for a high-voltage circuit, can control the sampling circuit in each sticking detection circuit to detect the voltage of the corresponding relay, and can control the output processing of one of the multiple voltage acquisition signals of the multiplexing module 103, and can receive and process the output signal to complete the detection of the relay sticking condition. In addition, by providing the multiplexing module 103 between the sampling circuit and the microcontroller unit, the analog IO port resources of the microcontroller unit can be conserved.

[0044] According to an embodiment of the present application, the constant current control module 104 includes a first resistor R1 , a second diode DH2 , and a third diode DH3 .

[0045] One end of the first resistor R1 is connected to the first power supply V1, and the other end is connected to the high-voltage sampling circuit 102. The anode of the third diode DH3 is connected to one end of the first resistor R1, and the cathode is connected to the anode of the second diode DH2. The cathode of the second diode DH2 is connected between the current-limiting resistor R3 and the high-voltage sampling circuit. The constant current control module 104 can provide a stable current to the entire circuit. Regardless of how the load changes and how much the change is, the constant current control module 104 can automatically adapt to the load changes, thereby enhancing the anti-interference capability of the entire circuit.

[0046] Specifically, the sampling circuit includes a high-voltage sampling circuit 102 and a low-voltage control module 105 . The low-voltage control module 105 is used to control the high-voltage sampling circuit 102 to collect the voltage at the rear end of the main negative relay K3 .

[0047] According to the embodiments of this application, reference Figure 2 The low voltage control module 105 includes an NPN transistor Q1 and a current limiting resistor R3.

[0048] The collector of the NPN transistor Q1 is connected to the high-voltage sampling circuit 102 through the current-limiting resistor R3. The base of the NPN transistor Q1 is connected to the micro control unit 106 to receive the control signal of the micro control unit 106. The emitter of the NPN transistor Q1 is connected to the negative electrode of the high-voltage power supply BAT.

[0049] That is, the relay adhesion detection circuit for the high-voltage circuit of the present application can be connected to the high-voltage sampling circuit 102 and the base of the NPN transistor Q1 through the collector of the NPN transistor Q1 to the micro-control unit 106. When it is necessary to detect one of the negative-side relays of multiple high-voltage power supplies, the micro-control unit 106 can output a response signal to the low-voltage control module 105 corresponding to the negative-side relay of the high-voltage power supply. The NPN transistor Q1 in the low-voltage control module 105 is turned on, and then the high-voltage sampling circuit 102 is turned on to collect the voltage of the negative-side relay of the high-voltage power supply. This method can flexibly control the voltage of the negative-side relays of different high-voltage power supplies to detect the adhesion of the negative-side relays of different high-voltage power supplies.

[0050] Furthermore, if Figure 1 、 Figure 2 and Figure 3 As shown, the high-voltage sampling circuit 102 includes a PNP transistor Q2 and a first diode DH1. The base of the PNP transistor Q2 is connected to one end of the current-limiting resistor R3, the collector of the PNP transistor Q2 is connected to the other end of the first resistor R1, the emitter of the PNP transistor is connected to the anode of the first diode DH1, and the cathode of the first diode DH1 is connected to the negative side of the high-voltage power supply via a detection line Link, which is the end of the relay away from the negative electrode of the high-voltage power supply BAT.

[0051] Specifically, in this embodiment, referring to Figure 1 and Figure 3 When the adhesion of the main negative relay K3 needs to be detected, the first power supply V1, the first resistor R1, the PNP transistor Q2, the first diode DH1, and the end of the main negative relay K3 away from the negative electrode of the high-voltage power supply BAT are connected in sequence. The voltage collection point is set between the first resistor R1 and the collector of the PNP transistor Q2. When the entire circuit is connected, the first diode DH1 will generate a forward voltage drop based on its own characteristics. The collected forward voltage drop is output to the micro control unit 106 through the multiplexing module 103, so that the micro control unit 106 can determine the adhesion of the main negative relay K3. Figure 2 and Figure 3When it is necessary to detect the adhesion condition of the fast-charging negative relay K5, the first power supply V1, the first resistor R1, the PNP transistor Q2, the first diode DH1 and the end of the fast-charging negative relay K5 away from the negative electrode of the high-voltage power supply BAT are connected in sequence, and the voltage collection point is set between the first resistor R1 and the collector of the PNP transistor Q2. When the entire circuit is connected, according to the characteristics of the first diode DH1 itself, it will generate a forward voltage drop. The collected forward voltage drop is output to the micro control unit 106 through the multiplexing module 103, so that the micro control unit 106 can judge the adhesion condition of the fast-charging negative relay K5.

[0052] In some embodiments, the relay adhesion detection circuit for the high-voltage circuit further includes a filter circuit module for filtering out external interference, and the filter circuit module includes a second resistor R2 and a first capacitor C1. One end of the second resistor R2 is connected to the base of the PNP transistor Q2, and the other end is connected to the signal input terminal of the multiplexer chip UH2. One end of the capacitor C1 is connected to the other end of the resistor R2, and the other end is connected to the negative electrode of the high-voltage power supply. Specifically, the setting of the filter circuit module can filter out interference signals in the voltage collected by the high-voltage sampling circuit 102, thereby improving the quality of the voltage signal and improving the accuracy of the relay adhesion detection.

[0053] Specifically, the multiplexer chip UH2 also includes a positive power pin VCC, a negative power pin VEE, a ground pin GND and a filter capacitor CH3. The positive power pin VCC is connected to the second power supply V2, the negative power pin VEE and the ground pin GND are connected to the negative electrode of the high-voltage power supply BAT, and the filter capacitor CH3 is connected between the second power supply V2 and the negative electrode of the high-voltage power supply BAT.

[0054] Preferably, the multiplexer chip UH2 is 74HC4051M.

[0055] For example, the first power supply V1 and the second power supply V2 are both 5 V DC voltages. The 5 V DC voltage can provide a stable DC voltage to the circuit, ensuring the safety and stability of the circuit.

[0056] Based on the same concept, the present invention also provides a battery management system, including the relay adhesion detection circuit for the high-voltage circuit as described above.

[0057] It should be noted that the unit modules mentioned in the various device embodiments of the present invention are all logical unit modules. Physically, a logical unit module can be a physical unit module, or a part of a physical unit module, or can be implemented as a combination of multiple physical unit modules. The physical implementation method of these logical unit modules themselves is not the most important. The combination of functions implemented by these logical unit modules is the key to solving the technical problems proposed by this application. In addition, in order to highlight the innovative part of this application, the above-mentioned device embodiments of the present invention do not introduce unit modules that are not closely related to solving the technical problems proposed by this utility model. This does not mean that other unit modules do not exist in the above-mentioned device embodiments.

[0058] It should be noted that, in the examples and description of the present utility model, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0059] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above description is provided to further illustrate the present invention in conjunction with specific embodiments, and that the present invention should not be construed as being limited to these descriptions. Those skilled in the art may make various changes in form and detail, including simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A relay adhesion detection circuit for a high voltage circuit, characterized in that: The high-voltage circuit includes a high-voltage power supply, a total positive relay, a pre-charge relay, a pre-charge resistor, a fast-charge positive relay, a negative-side relay of the high-voltage power supply, and a load. The detection circuit includes: a constant current control module, a sampling circuit, and a multiplexing module; wherein, The sampling circuit is used to collect the voltage at the rear end of the negative-side relay of the high-voltage power supply and is connected to the multiplexing module; The constant current control module is connected to the sampling circuit and is used to provide a stable current when the circuit is working; The multiplexing module includes at least one multiplexer chip (UH2) for expanding multiple detection IO port channels; wherein the multiplexer chip (UH2) includes multiple signal input terminals, signal output terminals and selection terminals; the multiple signal input terminals are connected to the voltage output terminal of the sampling circuit, the selection terminal is used to select one input signal from the multiple signal input terminals and output it to the signal output terminal, and the signal output terminal is used to output the signal input from the signal input terminal to determine whether the negative side relay of the high-voltage power supply is adhered.

2. The relay adhesion detection circuit for a high voltage circuit according to claim 1, wherein: The sampling circuit includes a high-voltage sampling circuit and a low-voltage control module. The low-voltage control module is used to control the high-voltage sampling circuit to collect the voltage at the rear end of the negative-side relay of the high-voltage power supply.

3. The relay adhesion detection circuit for a high voltage circuit according to claim 2, wherein: It also includes a micro control unit connected to the low voltage control module and receiving the signal output by the signal output end of the multiplexing module, for judging whether the negative side relay of the high voltage power supply is adhered.

4. The relay adhesion detection circuit for a high voltage circuit according to claim 3, wherein: The low-voltage control module includes an NPN transistor (Q1) and a current-limiting resistor (R3); The collector of the NPN transistor (Q1) is connected to the high-voltage sampling circuit via the current-limiting resistor (R3); the base of the NPN transistor (Q1) is connected to the microcontroller unit to receive a control signal from the microcontroller unit; and the emitter of the NPN transistor (Q1) is connected to the negative electrode of the high-voltage power supply.

5. The relay adhesion detection circuit for a high voltage circuit according to claim 4, wherein: The constant current control module includes a first resistor (R1), a second diode (DH2) and a third diode (DH3); One end of the first resistor (R1) is connected to the first power supply (V1), and the other end is connected to the high-voltage sampling circuit; The anode of the third diode (DH3) is connected to the one end of the first resistor (R1), and the cathode is connected to the anode of the second diode (DH2); the cathode of the second diode (DH2) is connected between the current limiting resistor (R3) and the high-voltage sampling circuit.

6. The relay adhesion detection circuit for a high voltage circuit according to claim 5, wherein: The high-voltage sampling circuit includes a PNP transistor (Q2) and a first diode (DH1); The base of the PNP transistor (Q2) is connected to one end of the current-limiting resistor (R3), the collector of the PNP transistor (Q2) is connected to the other end of the first resistor (R1), the emitter of the PNP transistor is connected to the anode of the first diode (DH1), and the cathode of the first diode (DH1) is connected to the negative electrode side of the high-voltage power supply through a detection line (Link) and an end of the relay away from the negative electrode of the high-voltage power supply.

7. The relay adhesion detection circuit for a high voltage circuit according to claim 6, wherein: It also includes a filter circuit module for filtering out external interference, and the filter circuit module includes a second resistor (R2) and a first capacitor (C1); One end of the second resistor (R2) is connected to the base of the PNP transistor (Q2), and the other end is connected to the signal input end of the multiplexer chip; One end of the capacitor (C1) is connected to the other end of the resistor (R2), and the other end is connected to the negative electrode of the high-voltage power supply.

8. The relay adhesion detection circuit for a high voltage circuit according to claim 7, wherein: The multiplexer chip further includes a positive power pin, a negative power pin, a ground pin, and a filter capacitor (CH3), wherein the positive power pin is connected to a second power supply (V2), the negative power pin is connected to a negative electrode of the high-voltage power supply, and the filter capacitor (CH3) is connected between the second power supply (V2) and the negative electrode of the high-voltage power supply.

9. The relay adhesion detection circuit for a high voltage circuit according to claim 8, wherein: The negative side relay of the high voltage power supply is a total negative relay or a fast charging negative relay.

10. The relay adhesion detection circuit for a high voltage circuit according to claim 9, characterized in that: The first power supply (V1) and the second power supply (V2) are both 5V DC voltage.

11. A battery management system, characterized in that: The invention comprises a relay adhesion detection circuit for a high-voltage circuit as described in any one of claims 1 to 10.

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