BMS (Battery Management System) protection system with 485 and CAN (Controller Area Network) dual communication
By designing the switching circuit of the BMS protection system with 485 and CAN dual communication systems, the problem of resource waste and cost increase caused by the separation of the Can and the RS485 communication module in the existing solutions, and the switching 485 and CAN communication in the same integrated circuit. Reduce electronic materials and PCB area and reduce costs.
Patent Information
- Application Number
- CN202420284235.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-06
- Publication Date
- 2025-01-28
- Estimated Expiration
- 2034-02-06
AI Technical Summary
In the existing solution, the CAN communication module circuit and the RS485 communication module circuit are separated, resulting in an increase in electronic materials, an increase in PCB area, an increase in cost and waste of resources.
A BMS protection system with 485 and CAN dual communication is designed to switch between the CAN and 485 circuits by switching circuits. The switching circuit includes 485 control circuits, CAN control circuits, communication isolation circuits, interrupt wake -up circuits, and first interface circuits. Signal, interrupt wake -up circuit to achieve communication awakening.
In the same integrated circuit, the switching of 485 communication and CAN communication is achieved, reducing the area of electronic materials and PCB, and reducing costs and resources waste.
Smart Images
Figure CN222423898U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of bus communication, in particular to a BMS protection system with 485 and CAN dual communications. Background Art
[0002] CAN bus and 485 bus are both common serial communication protocols, which are widely used in industrial automation, robot control and other fields. 485 bus is a half-duplex, full-duplex asynchronous communication bus, which was created to get rid of the low communication rate and short communication distance of 232 bus. 485 bus only specifies the electrical characteristics of the driver and receiver, but does not specify the connectors, transmission cables and application layer communication protocols, so it was a very affordable bus with a relatively high transmission rate at that time. CAN bus is a twisted pair with high anti-interference, high speed, and more importantly, it can detect any errors. CAN bus has the advantages of real-time communication capability, flexibility, long transmission distance, low reliability cost, etc., so it is considered to be the most promising field bus.
[0003] CAN bus is mainly used for high-speed data transmission and real-time control systems, such as automotive electronic control units (ECUs), industrial robots, etc. The 485 bus is mainly used for low-speed data transmission and data acquisition systems, such as data acquisition of sensors such as temperature, humidity, and pressure. RS-485 bus technology is an application layer protocol compared to the underlying layer. As an application developer, you generally focus on its application. You can understand it as a fixed hardware layer electrical interface. As for our application development based on the 485 hardware ready condition, we only need to consider its software communication protocol. There is a mainstream Modbus RTU communication protocol, or you can define your own set of protocol standards for corresponding transmission, as long as there is no data loss; if the device wants to communicate with 485, it needs to use the serial port as an intermediary to transfer the MCU data to the RS-485 bus and then continue to transmit, so a serial port to 485 circuit needs to be designed on the hardware circuit board. The 485 interface can be connected to external devices through a 485 twisted pair shielded cable, or it can be connected to a computer debugging assistant (Modbus) through a 485 to USB. The CAN bus has a reliable error handling and error detection mechanism. The node has the function of automatically exiting the bus in the event of a serious error. If the sent information is damaged, it can be automatically retransmitted. The bus arbitration can also be performed through the priority of the identifier to resolve the conflict of sending information. The 485 bus avoids data conflicts through a one-master-multiple-slave approach. The CAN bus is a standard bus for automotive control systems. CAN specifies the physical layer and link layer, while the 485 bus only specifies the electrical characteristics of the driver and receiver, but does not specify connectors, transmission cables, and application layer communication protocols. Both CAN and 485 are half-duplex differential transmission methods, which have certain requirements for wire materials, preferably shielded twisted pair cables, and both require 120-ohm terminal matching resistors to solve the problem of signal reflection.
[0004] In the current existing solution, the CAN communication module circuit and the RS485 communication module circuit are separated, which not only increases the electronic materials, but also leads to an increase in the PCB area, resulting in a certain degree of cost increase and resource waste. Utility Model Content
[0005] In order to overcome the deficiencies of the prior art, the purpose of the utility model is to provide a BMS protection system based on 485 and CAN dual communications, which can realize communication switching between CAN circuits and 485 circuits.
[0006] The purpose of the utility model is achieved by the following technical solutions:
[0007] The utility model provides a BMS protection system with 485 and CAN dual communications, including a switching circuit, the switching circuit including a 485 control circuit, a CAN control circuit, a communication isolation circuit, an interrupt wake-up circuit, and a first interface circuit, the 485 control circuit also includes a 485 circuit, a second interface circuit and an interactive circuit, the interactive connection, the 485 circuit and the second interface circuit are connected in sequence, the first interface circuit is connected to the communication isolation circuit, the CAN control circuit and the 485 circuit are both connected to the communication isolation circuit, the 485 circuit is connected to the CAN control circuit, and the 485 control circuit is connected to the interrupt wake-up circuit.
[0008] In the utility model, as an optional embodiment, the first interface circuit includes an interface J5, a resistor R22, a resistor R23, a resistor R18, a resistor R19, a resistor R136, a resistor R137, a diode D32, and a diode D33. One end of the resistor R22 and one end of the resistor R23 are both connected to the interface J5, the other end of the resistor R23, one end of the resistor R136, and the cathode of the diode D32 are all connected to one end of the resistor R19, the other end of the resistor R22, one end of the resistor R137, and the cathode of the diode D33 are all connected to one end of the resistor R18, and the other end of the resistor R18 and the other end of the resistor R19 are both connected to the communication isolation circuit.
[0009] In the present utility model, as an optional embodiment, the communication isolation circuit includes an isolation chip U8, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R135, a resistor R158, a resistor R159, a resistor R34, a resistor R35, a diode D45 and a field effect transistor Q28, one end of the resistor R159 is connected to the resistor R18, and one end of the resistor R158 is connected to the resistor R19, one end of the resistor R14, one end of the resistor R13, the other end of the resistor R158 and the diode D45 are connected to the resistor R19. The other end of resistor R159 is connected to the isolation chip U8, one end of resistor R15 and one end of resistor R16 are connected to the isolation chip U8, the other end of resistor R15 and the other end of resistor R16 are connected to the CAN control circuit and the 458 circuit, the positive electrode of diode D45 is connected to one end of resistor R34, the other end of resistor R34 and one end of resistor R135 are connected to the gate of field effect transistor Q28, the drain of field effect transistor Q28 is connected to the other end of resistor R135, and the source of field effect transistor Q28 is connected to the isolation chip U8.
[0010] In the present utility model, as an optional embodiment, the CAN control circuit includes a first signal conversion chip U12, a resistor R20, a resistor R21, a resistor R173, a resistor R174, a resistor R175, a resistor R176, a resistor R97, a resistor R96, a resistor PTC1, a resistor PTC2, a capacitor C67, a bidirectional diode TVS1 and a bidirectional diode TVS2, one end of the resistor R20 and one end of the resistor R21 are connected to the isolation chip U8, the other end of the resistor R20 and the other end of the resistor R21 are connected to the first signal conversion chip U12, one end of the resistor R97 and the resistor PTC2 One end is connected to one end of the bidirectional diode TVS2, one end of the resistor R96 and one end of the resistor PTC1 are connected to the bidirectional diode TVS1, the other end of the resistor R97 and the other end of the resistor R96 are connected to the first signal conversion chip U12, the other end of the resistor PTC1 and the other end of the resistor PTC2 are connected to the 485 circuit, one end of the resistor R173, one end of the resistor R174 and one end of the resistor R175 are connected to the first signal conversion chip U12, the other end of the resistor R173, the other end of the resistor R174 and the other end of the resistor R175 are connected to one end of the capacitor C67, and the other end of the capacitor C67 is grounded.
[0011] In the utility model, as an optional embodiment, the interrupt wake-up circuit includes a capacitor C17, an optocoupler U10, a resistor R170 and a resistor R171, one end of the resistor R171 and one end of the resistor R170 are connected to the 485 circuit, the other end of the resistor R171 and the other end of the resistor R170 are connected, and the connection between the resistor R171 and the resistor R170 is connected to the control end of the optocoupler U10, one end of the capacitor C17 is connected to the receiving end of the optocoupler U10, and the other end of the capacitor C17 is grounded.
[0012] In the utility model, as an optional embodiment, the second interface circuit includes an interface J2, a diode D34, and a diode D35, the cathode of the diode D34 is connected to one of the pins of the interface J2, the cathode of the diode D35 is connected to another pin of the interface J2, the cathode of the diode D34 and the cathode of the diode D35 are also connected to the 458 circuit, and the anode of the diode D34 and the anode of the diode D35 are both grounded.
[0013] In the present utility model, as an optional embodiment, the 485 circuit includes a second signal conversion chip U13, a resistor R17, a resistor R98, a resistor R99, a capacitor C70, a capacitor C71, a diode D11, a diode D9, a diode D12, and a diode D10. One end of the resistor R99 is connected to the cathode of the diode D34, one end of the resistor R98 is connected to the cathode of the diode D35, one end of the capacitor C71, the cathode of the diode D11 and the other end of the resistor R99 are all connected to the second signal conversion chip U13, the cathode of the diode D12, the other end of the resistor R98 and one end of the capacitor C70 are all connected to the second signal conversion chip U13, the anode of the diode D12 is connected to the anode of the diode D10, the other end of the capacitor C71 is connected between the diode D12 and the diode D10, the anode of the diode D11 is connected to the anode of the diode D9, one end of the capacitor C70 is connected between the diode D11 and the diode D9, and the cathode of the diode D9 and the cathode of the diode D10 are both grounded.
[0014] Compared with the prior art, the beneficial effects of the present invention are:
[0015] The utility model discloses a BMS protection system with 485 and CAN dual communications, which includes a switching circuit. The switching circuit includes a 485 control circuit, a CAN control circuit, a communication isolation circuit, an interrupt wake-up circuit, and a first interface circuit. The MCU and external communication high voltage can be isolated through the communication isolation circuit. When 485 communication is required, the 485 control circuit converts the signal into a 485 communication differential signal. When CAN communication is required, the CAN control circuit converts the signal into a CAN communication differential signal. External 485 signals and CAN signals can realize communication wake-up through an interrupt wake-up circuit. The switching circuit provided by the utility model can realize switching between 485 communication and CAN communication in the same integrated circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a schematic diagram of the circuit module structure of a switching circuit of a BMS protection system with 485 and CAN dual communications according to an embodiment of the utility model;
[0017] Figure 2 A schematic diagram of the circuit structure of a first interface circuit according to an embodiment of the present utility model;
[0018] Figure 3 A schematic diagram of the circuit structure of a communication isolation circuit according to an embodiment of the present utility model;
[0019] Figure 4 This is a schematic diagram of the circuit structure of the CAN control circuit of an embodiment of the utility model;
[0020] Figure 5A schematic diagram of the circuit structure of an interrupt wake-up circuit according to an embodiment of the utility model;
[0021] Figure 6 It is a schematic diagram of the circuit structure of the 458 circuit and the second interface circuit of an embodiment of the utility model. DETAILED DESCRIPTION
[0022] Below, in conjunction with the accompanying drawings and specific implementation methods, the utility model is further described. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form a new embodiment. Except for special instructions, the materials and equipment used in this embodiment can be purchased from the market. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0023] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "plurality" means two or more, unless otherwise precisely and specifically specified.
[0024] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be connected through an intermediary medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0025] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0026] An embodiment of the present application provides a BMS protection system with 485 and CAN dual communications, including a switching circuit. The switching circuit includes a 485 control circuit, a CAN control circuit, a communication isolation circuit, an interrupt wake-up circuit, and a first interface circuit. The MCU and external communication high voltage can be isolated through the communication isolation circuit. When 485 communication is required, it is converted into a 485 communication differential signal through the 485 control circuit. When CAN communication is required, it is converted into a CAN communication differential signal through the CAN control circuit. External 485 signals and CAN signals can realize communication wake-up through the interrupt wake-up circuit. The switching circuit provided by the utility model can realize switching between 485 communication and CAN communication in the same integrated circuit.
[0027] Please refer to Figure 1 As shown, the BMS protection system with 485 and CAN dual communications provided in this embodiment includes a switching circuit, the switching circuit includes a 485 control circuit, a CAN control circuit, a communication isolation circuit, an interrupt wake-up circuit, and a first interface circuit, the 485 control circuit also includes a 485 circuit, a second interface circuit and an interactive circuit, the interactive connection, the 485 circuit and the second interface circuit are connected in sequence, the first interface circuit is connected to the communication isolation circuit, the CAN control circuit and the 485 circuit are both connected to the communication isolation circuit, the 485 circuit is connected to the CAN control circuit, and the 485 control circuit is connected to the interrupt wake-up circuit.
[0028] Specifically, Figure 2 As shown, the first interface circuit includes an interface J5, a resistor R22, a resistor R23, a resistor R18, a resistor R19, a resistor R136, a resistor R137, a diode D32, and a diode D33. One end of the resistor R22 and one end of the resistor R23 are both connected to the interface J5, the other end of the resistor R23, one end of the resistor R136, and the cathode of the diode D32 are all connected to one end of the resistor R19, the other end of the resistor R22, one end of the resistor R137, and the cathode of the diode D33 are all connected to one end of the resistor R18, and the other end of the resistor R18 and the other end of the resistor R19 are both connected to the communication isolation circuit.
[0029] like Figure 3As shown, the communication isolation circuit includes an isolation chip U8, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R135, a resistor R158, a resistor R159, a resistor R34, a resistor R35, a diode D45 and a field effect transistor Q28, one end of the resistor R159 is connected to the resistor R18, and one end of the resistor R158 is connected to the resistor R19, one end of the resistor R14, one end of the resistor R13, the other end of the resistor R158 and the other end of the resistor R159 Both are connected to the isolation chip U8, one end of the resistor R15 and one end of the resistor R16 are connected to the isolation chip U8, the other end of the resistor R15 and the other end of the resistor R16 are both connected to the CAN control circuit and the 458 circuit, the positive electrode of the diode D45 is connected to one end of the resistor R34, the other end of the resistor R34 and one end of the resistor R135 are both connected to the gate of the field effect transistor Q28, the drain of the field effect transistor Q28 is connected to the other end of the resistor R135, and the source of the field effect transistor Q28 is connected to the isolation chip U8.
[0030] like Figure 4 As shown, the CAN control circuit includes a first signal conversion chip U12, a resistor R20, a resistor R21, a resistor R173, a resistor R174, a resistor R175, a resistor R176, a resistor R97, a resistor R96, a resistor PTC1, a resistor PTC2, a capacitor C67, a bidirectional diode TVS1 and a bidirectional diode TVS2, one end of the resistor R20 and one end of the resistor R21 are connected to the isolation chip U8, the other end of the resistor R20 and the other end of the resistor R21 are connected to the first signal conversion chip U12, one end of the resistor R97 and one end of the resistor PTC2 are connected to the bidirectional diode One end of the tube TVS2, one end of the resistor R96 and one end of the resistor PTC1 are all connected to the bidirectional diode TVS1, the other end of the resistor R97 and the other end of the resistor R96 are all connected to the first signal conversion chip U12, the other end of the resistor PTC1 and the other end of the resistor PTC2 are connected to the 485 circuit, one end of the resistor R173, one end of the resistor R174 and one end of the resistor R175 are all connected to the first signal conversion chip U12, the other end of the resistor R173, the other end of the resistor R174 and the other end of the resistor R175 are all connected to one end of the capacitor C67, and the other end of the capacitor C67 is grounded.
[0031] like Figure 5 As shown, the interrupt wake-up circuit includes a capacitor C17, an optocoupler U10, a resistor R170 and a resistor R171, one end of the resistor R171 and one end of the resistor R170 are connected to the 485 circuit, the other end of the resistor R171 and the other end of the resistor R170 are connected, and the connection between the resistor R171 and the resistor R170 is connected to the control end of the optocoupler U10, one end of the capacitor C17 is connected to the receiving end of the optocoupler U10, and the other end of the capacitor C17 is grounded.
[0032] like Figure 6 As shown, the second interface circuit includes an interface J2, a diode D34, and a diode D35, wherein the cathode of the diode D34 is connected to one of the pins of the interface J2, the cathode of the diode D35 is connected to another pin of the interface J2, the cathode of the diode D34 and the cathode of the diode D35 are also connected to the 458 circuit, and the anode of the diode D34 and the anode of the diode D35 are both grounded. The 485 circuit includes a second signal conversion chip U13, a resistor R17, a resistor R98, a resistor R99, a capacitor C70, a capacitor C71, a diode D11, a diode D9, a diode D12, and a diode D10. One end of the resistor R99 is connected to the cathode of the diode D34, one end of the resistor R98 is connected to the cathode of the diode D35, one end of the capacitor C71, the cathode of the diode D11, and the other end of the resistor R99 are all connected to the second signal conversion chip U13, the cathode of the diode D12, the other end of the resistor R98, and one end of the capacitor C70 are all connected to the second signal conversion chip U13, the anode of the diode D12 is connected to the anode of the diode D10, the other end of the capacitor C71 is connected between the diode D12 and the diode D10, the anode of the diode D11 is connected to the anode of the diode D9, one end of the capacitor C70 is connected between the diode D11 and the diode D9, and the cathode of the diode D9 and the cathode of the diode D10 are both grounded.
[0033] In the above, the working principle of the embodiment is as follows: U8 is a 485 / CAN communication isolation chip, which can isolate the MCU from the external communication high voltage. When 485 communication is required, only the device of the 485 module needs to be attached, and U13 (ISL3152) can convert the UART communication TTL signal into a 485 communication differential signal. The MCU controls U13 to send and receive data through U9. In addition, the 485 signal can be realized by controlling the MCU wake-up interrupt through the optocoupler U10 to realize communication wake-up. When CAN communication is required, only the device of the CAN module needs to be attached, and U12 (MCP2561) can convert the UART communication TTL signal into a CAN communication differential signal. In addition, the CAN signal can be realized by controlling the MCU wake-up interrupt through U10 (optocoupler); in addition, due to the particularity of CAN communication, the MCU cannot share the internal UART and CAN pins, and needs to use 2 separate designated I / O ports independently.
[0034] Although only certain components and embodiments of the present application have been illustrated and described, many modifications and changes may be conceived by those skilled in the art without actually departing from the scope and spirit of the claims, such as changes in the size, dimensions, structure, shape and proportion of the various elements, mounting arrangements, material usage, color, orientation, etc.
[0035] The above-mentioned implementation mode is only a preferred implementation mode of the embodiment of the utility model, and cannot be used to limit the scope of protection of the embodiment of the utility model. Any non-substantial changes and replacements made by technical personnel in this field on the basis of the embodiment of the utility model shall fall within the scope of protection required by the embodiment of the utility model.
Claims
1. A BMS protection system with 485 and CAN dual communications, characterized by: It includes a switching circuit, which includes a 485 control circuit, a CAN control circuit, a communication isolation circuit, an interrupt wake-up circuit, and a first interface circuit. The 485 control circuit also includes a 485 circuit, a second interface circuit and an interactive circuit. The interactive connection, the 485 circuit and the second interface circuit are connected in sequence. The first interface circuit is connected to the communication isolation circuit, the CAN control circuit and the 485 circuit are both connected to the communication isolation circuit, the 485 circuit is connected to the CAN control circuit, and the 485 control circuit is connected to the interrupt wake-up circuit.
2. The BMS protection system according to claim 1, characterized in that: The first interface circuit includes an interface J5, a resistor R22, a resistor R23, a resistor R18, a resistor R19, a resistor R136, a resistor R137, a diode D32, and a diode D33. One end of the resistor R22 and one end of the resistor R23 are both connected to the interface J5, the other end of the resistor R23, one end of the resistor R136, and the cathode of the diode D32 are all connected to one end of the resistor R19, the other end of the resistor R22, one end of the resistor R137, and the cathode of the diode D33 are all connected to one end of the resistor R18, and the other end of the resistor R18 and the other end of the resistor R19 are both connected to the communication isolation circuit.
3. The BMS protection system according to claim 2, characterized in that: The communication isolation circuit includes an isolation chip U8, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R135, a resistor R158, a resistor R159, a resistor R34, a resistor R35, a diode D45 and a field effect transistor Q28, one end of the resistor R159 is connected to the resistor R18, one end of the resistor R158 is connected to the resistor R19, one end of the resistor R14, one end of the resistor R13, the other end of the resistor R158 and the other end of the resistor R159 are all ...9 is connected to the resistor R18, one end of The isolation chip U8 is connected, one end of the resistor R15 and one end of the resistor R16 are connected to the isolation chip U8, the other end of the resistor R15 and the other end of the resistor R16 are both connected to the CAN control circuit and the 458 circuit, the positive electrode of the diode D45 is connected to one end of the resistor R34, the other end of the resistor R34 and one end of the resistor R135 are both connected to the gate of the field effect transistor Q28, the drain of the field effect transistor Q28 is connected to the other end of the resistor R135, and the source of the field effect transistor Q28 is connected to the isolation chip U8.
4. The BMS protection system according to claim 3, characterized in that: The CAN control circuit includes a first signal conversion chip U12, a resistor R20, a resistor R21, a resistor R173, a resistor R174, a resistor R175, a resistor R176, a resistor R97, a resistor R96, a resistor PTC1, a resistor PTC2, a capacitor C67, a bidirectional diode TVS1 and a bidirectional diode TVS2, one end of the resistor R20 and one end of the resistor R21 are connected to the isolation chip U8, the other end of the resistor R20 and the other end of the resistor R21 are connected to the first signal conversion chip U12, one end of the resistor R97 and one end of the resistor PTC2 are connected to the bidirectional diode One end of the tube TVS2, one end of the resistor R96 and one end of the resistor PTC1 are all connected to the bidirectional diode TVS1, the other end of the resistor R97 and the other end of the resistor R96 are all connected to the first signal conversion chip U12, the other end of the resistor PTC1 and the other end of the resistor PTC2 are connected to the 485 circuit, one end of the resistor R173, one end of the resistor R174 and one end of the resistor R175 are all connected to the first signal conversion chip U12, the other end of the resistor R173, the other end of the resistor R174 and the other end of the resistor R175 are all connected to one end of the capacitor C67, and the other end of the capacitor C67 is grounded.
5. The BMS protection system according to claim 4, characterized in that: The interrupt wake-up circuit includes a capacitor C17, an optocoupler U10, a resistor R170 and a resistor R171, one end of the resistor R171 and one end of the resistor R170 are connected to the 485 circuit, the other end of the resistor R171 and the other end of the resistor R170 are connected, and the connection between the resistor R171 and the resistor R170 is connected to the control end of the optocoupler U10, one end of the capacitor C17 is connected to the receiving end of the optocoupler U10, and the other end of the capacitor C17 is grounded.
6. The BMS protection system according to claim 5, characterized in that: The second interface circuit includes an interface J2, a diode D34, and a diode D35. The cathode of the diode D34 is connected to one of the pins of the interface J2, and the cathode of the diode D35 is connected to another pin of the interface J2. The cathode of the diode D34 and the cathode of the diode D35 are also connected to the 458 circuit, and the anode of the diode D34 and the anode of the diode D35 are both grounded.
7. The BMS protection system according to claim 6, characterized in that: The 485 circuit includes a second signal conversion chip U13, a resistor R17, a resistor R98, a resistor R99, a capacitor C70, a capacitor C71, a diode D11, a diode D9, a diode D12, and a diode D10. One end of the resistor R99 is connected to the cathode of the diode D34, one end of the resistor R98 is connected to the cathode of the diode D35, one end of the capacitor C71, the cathode of the diode D11, and the other end of the resistor R99 are all connected to the second signal conversion chip U13, the cathode of the diode D12, the other end of the resistor R98, and one end of the capacitor C70 are all connected to the second signal conversion chip U13, the anode of the diode D12 is connected to the anode of the diode D10, the other end of the capacitor C71 is connected between the diode D12 and the diode D10, the anode of the diode D11 is connected to the anode of the diode D9, one end of the capacitor C70 is connected between the diode D11 and the diode D9, and the cathode of the diode D9 and the cathode of the diode D10 are both grounded.