A charging pile mainboard isolation power supply circuit

Abstract

The utility model discloses a charging pile mainboard isolation power supply circuit, include: isolation power module, digital isolation module, CAN transceiver module, MCU control module, peripheral circuit module, MCU control module connects digital isolation module, and digital isolation module is connected with isolation power module and CAN transceiver module, and isolation power module is connected with CAN transceiver module, and CAN transceiver module is connected with peripheral circuit module. The traditional charging pile considers the electrical environment difference and the security risk existing between the charging pile and electric automobile, adds the isolation between some information feedback and communication between the charging pile mainboard and BMS, and the utility model uses power module and isolation power module as the power supply of CAN circuit, replaces the power supply of conventional isolation power module. The utility model discloses a simple LDO instead of isolation power supply, thereby can reduce the cost of entire CAN circuit greatly.

Description

Technical Field

[0001] This utility model relates to the field of isolated power supply technology, specifically to an isolated power supply circuit for a charging pile motherboard. Background Technology

[0002] With the popularization of new energy vehicles, the design of charging piles has attracted much attention in the industry. CAN communication, as the main communication method between charging piles and new energy vehicles, is a key aspect of the technical field in terms of circuit design. The CAN circuit structure mainly consists of a digital isolation IC, a CAN transceiver, an isolation power supply, and peripheral protection circuitry; the circuit structure is generally fixed. Since CAN is the primary communication method between charging piles and electric vehicles, isolation between them is typically achieved using ordinary optocouplers or digital isolation chips. This requires a power supply isolated from the charging pile's mainboard to power these isolated components. Conventional solutions use isolation power supply modules or separate isolation power supplies, which are costly to use and maintain. Utility Model Content

[0003] To solve the above-mentioned technical problems, this utility model provides a charging pile motherboard isolation power supply circuit, including: an isolation power supply module, a digital isolation module, a CAN transceiver module, an MCU control module, and a peripheral circuit module;

[0004] The MCU control module is connected to the digital isolation module, the digital isolation module is connected to the isolation power supply module and the CAN transceiver module, the isolation power supply module is connected to the CAN transceiver module, and the CAN transceiver module is connected to the peripheral circuit module.

[0005] In the isolated power supply module, the VIN terminal of the isolated power supply chip U4 is connected to the inductor L1 and the capacitor C4. The other end of the inductor L1 is connected to the 5V voltage source and the capacitor C3. The other end of the capacitor C4 is connected to the GND terminal of the isolated power supply chip U4. Both are grounded at the same time, and the other end of the capacitor C3 is grounded.

[0006] The GND terminal of the isolation power chip U4 is connected to capacitor C7, the other end of capacitor C7 is connected to capacitor C8, and the other end of capacitor C8 is connected to the -V0 terminal of the digital isolation chip U4.

[0007] The +V0 terminal of the isolation power supply chip U4 is connected to inductor L2 and capacitor C5. The other end of inductor L2 is connected to capacitor C6, and the other end of capacitor C5 is connected to the -V0 terminal of isolation power supply U4. Resistors R8 and R9 are connected in parallel across capacitor C6.

[0008] Furthermore, the digital isolation module in this utility model includes:

[0009] The OUTB terminal of digital isolation chip U1 is connected to resistor R2, and the other end of resistor R2 serves as the CAN1_RX port; the INA terminal of digital isolation chip U1 is connected to resistor R4, and the other end of resistor R4 serves as the CAN1_TX terminal; the INB terminal of digital isolation chip U1 is connected to resistor R3, and the other end of resistor R3 is connected to the CAN transceiver module; the OUTA terminal of digital isolation chip U1 is connected to resistor R5, and the other end of resistor R5 is connected to the CAN transceiver module.

[0010] Furthermore, the CAN transceiver module of this utility model includes: the RXD port of the CAN transceiver U2 is connected to the resistor R3 of the peripheral circuit module, the TXD terminal of the CAN transceiver U2 is connected to the resistor R5 of the peripheral circuit module; the STB terminal of the CAN transceiver U2 is connected to the resistor R1, and the resistor R1 serves as the QCAN1 port connected to the isolated power supply module.

[0011] The CANH terminal of CAN transceiver U2 is connected to port 3 of common mode choke U3, and the CANL terminal of CAN transceiver U2 is connected to port 4 of common mode choke U3.

[0012] The NC terminal of CAN transceiver U2 is connected to resistor R9. The other end of resistor R9 is connected to resistor R6, resistor R7 and capacitor C11. The other end of resistor R6 is connected to port 1 of common mode choke U3. The other end of resistor R7 is connected to port 2 of common mode choke U3. The other end of capacitor C11 serves as QCAN1 port.

[0013] Capacitor C1 is connected to port 1 of common mode choke U3, and the other end is connected to capacitor C2. The other end of capacitor C2 is connected to port 2 of common mode choke U3.

[0014] The two ends of the voltage suppression diode Z1 are connected to port 1 and port 2 of the common-mode choke U3, respectively;

[0015] One end of voltage suppression diode Z2 is connected to voltage suppression diode Z3, and the other end is connected to port 1 of common mode choke U3. The other end of voltage suppression diode Z3 is connected to port 2 of common mode choke U3.

[0016] Furthermore, the isolated power supply module of this utility model also includes: a capacitor C11 connected to the VIN terminal of the LDO power chip U5, the other end of the capacitor C11 connected to the GND terminal of the LDO power chip U5, and a capacitor C10 connected in parallel across the two ends of the capacitor C11;

[0017] The VOUT terminal of the LDO power chip U5 is connected to capacitor C12, and the other end of capacitor C12 is connected to the GND terminal of the LDO power chip U5. Capacitor C13 is connected in parallel across capacitor C12, with one end serving as the 5VCAN1 port and the other end serving as the GCAN1 port.

[0018] The beneficial effects of this utility model are reflected in:

[0019] This invention replaces the isolated power supply with a simple LDO, thereby significantly reducing the cost of the entire CAN circuit. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0021] Figure 1 This is a schematic diagram of the CAN circuit structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the CAN circuit of the charging pile of this utility model;

[0023] Figure 3 This is the schematic diagram of DC charging safety protection for System B in standard GB-T18487.1. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0025] like Figure 1 As shown, this utility model provides an isolated power supply circuit for a charging pile motherboard, including: an isolated power supply module, a digital isolation module, a CAN transceiver module, an MCU control module, and a peripheral circuit module;

[0026] The MCU control module is connected to the digital isolation module, which in turn is connected to the isolation power supply module and the CAN transceiver module. The isolation power supply module is connected to the CAN transceiver module, and the CAN transceiver module is connected to the peripheral circuit module.

[0027] like Figure 2 As shown, the isolated power supply module includes: an isolated power supply chip U4, inductors L1 and L2, resistors R8 and R9, and capacitors C3, C4, C5, C6, C7, and C8.

[0028] Among them, the VIN terminal of the isolation power chip U4 is connected to the inductor L1 and the capacitor C4. The other end of the inductor L1 is connected to the 5V voltage source and the capacitor C3. The other end of the capacitor C4 is connected to the GND terminal of the isolation power chip U4. Both are grounded at the same time. The other end of the capacitor C3 is grounded.

[0029] The GND terminal of the isolation power chip U4 is connected to capacitor C7, the other end of capacitor C7 is connected to capacitor C8, and the other end of capacitor C8 is connected to the -V0 terminal of the digital isolation chip U4.

[0030] The +V0 terminal of the isolation power supply chip U4 is connected to inductor L2 and capacitor C5. The other end of inductor L2 is connected to capacitor C6, and the other end of capacitor C5 is connected to the -V0 terminal of isolation power supply U4. Resistors R8 and R9 are connected in parallel across capacitor C6.

[0031] In the isolated power supply module, the inductors L1 and L2 on the input and output sides are mainly used to suppress noise backflow from high-frequency switching, smooth current, and reduce EMI. The capacitors C3, C4, C5, and C6 on the input and output sides are mainly used to provide a low-impedance energy source, filter out high-frequency noise, and stabilize the input and output voltages.

[0032] R8 and R10 are dummy loads for the isolation power supply. Their functions are: to force the feedback loop into a stable operating range, ensuring the output voltage remains precisely stable within the error range under no-load / light-load conditions; and to provide an energy discharge circuit to protect internal components. Capacitors C7 and C8 between GND and GCAN create a low-impedance high-frequency path, allowing common-mode noise current to return to its source (rather than through the load or ground), significantly reducing radiated noise and improving EMC performance. The input voltage VCC5V of U4 is the system voltage on the low-voltage side of the charging pile motherboard, and the output voltage 5VCAN is the isolated output voltage.

[0033] The isolated power supply module also includes: LDO power chip U5, capacitors C10, C11, C12, and C13;

[0034] The VIN terminal of the LDO power chip U5 is connected to capacitor C11, and the other end of capacitor C11 is connected to the GND terminal of the LDO power chip U5. Capacitor C10 is connected in parallel across capacitor C11.

[0035] The VOUT terminal of the LDO power chip U5 is connected to capacitor C12, and the other end of capacitor C12 is connected to the GND terminal of the LDO power chip U5. Capacitor C13 is connected in parallel across capacitor C12, with one end serving as the 5VCAN1 port and the other end serving as the GCAN1 port.

[0036] The input and output capacitors in the power module are mainly used to provide a low-impedance energy source, filter high-frequency noise, and stabilize the input and output voltages. VFY provides low-voltage output power to the charging pile, primarily supplying power to the BMS (Battery Management System) of the new energy vehicle during charging.

[0037] The CAN transceiver module includes: CAN transceiver U2, common mode choke U3, resistors R1, R6, R7, and R9, capacitors C1, C2, and C11, and voltage suppression diodes Z1, Z2, and Z3.

[0038] The RXD port of CAN transceiver U2 is connected to resistor R3 of the peripheral circuit module, and the TXD terminal of CAN transceiver U2 is connected to resistor R5 of the peripheral circuit module; the STB terminal of CAN transceiver U2 is connected to resistor R1, and resistor R1 is used as the QCAN1 port to connect to the isolated power supply module.

[0039] The CANH terminal of CAN transceiver U2 is connected to port 3 of common mode choke U3, and the CANL terminal of CAN transceiver U2 is connected to port 4 of common mode choke U3.

[0040] The NC terminal of CAN transceiver U2 is connected to resistor R9. The other end of resistor R9 is connected to resistor R6, resistor R7 and capacitor C11. The other end of resistor R6 is connected to port 1 of common mode choke U3. The other end of resistor R7 is connected to port 2 of common mode choke U3. The other end of capacitor C11 serves as QCAN1 port.

[0041] Capacitor C1 is connected to port 1 of common mode choke U3, and the other end is connected to capacitor C2. The other end of capacitor C2 is connected to port 2 of common mode choke U3.

[0042] The two ends of the voltage suppression diode Z1 are connected to port 1 and port 2 of the common-mode choke U3, respectively;

[0043] One end of voltage suppression diode Z2 is connected to voltage suppression diode Z3, and the other end is connected to port 1 of common mode choke U3. The other end of voltage suppression diode Z3 is connected to port 2 of common mode choke U3.

[0044] In the CAN transceiver module, U3 is a common-mode choke primarily to reduce common-mode radiation. R6 / R7 are CAN terminating resistors, mainly to provide a current loop for the signal, absorb reflected energy at the end of the transmission line, and prevent signal oscillation. C1 / C2 are mainly used to filter out high-frequency noise. Z1 / Z2 / Z3 are TVS resistors, mainly to prevent surge voltage and protect the circuit.

[0045] The digital isolation module includes: digital isolation chip U1, resistors R2, R3, R4, and R5;

[0046] The OUTB terminal of digital isolation chip U1 is connected to resistor R2, and the other end of resistor R2 serves as the CAN1_RX port; the INA terminal of digital isolation chip U1 is connected to resistor R4, and the other end of resistor R4 serves as the CAN1_TX terminal; the INB terminal of digital isolation chip U1 is connected to resistor R3, and the other end of resistor R3 is connected to the CAN transceiver module; the OUTA terminal of digital isolation chip U1 is connected to resistor R5, and the other end of resistor R5 is connected to the CAN transceiver module.

[0047] Among them, resistors R2, R3, R4, and R5 are mainly used to reduce signal reflection and lower EMI.

[0048] like Figure 3 The diagram shown is the DC charging safety protection schematic for System B in standard GB-T18487.1. Figure 3 Switches S3 / S4 are internal control switches for the low-voltage auxiliary power supply circuit of the charging pile. They close after the charging gun is inserted into the electric vehicle to supply power to the vehicle's BMS. The charging pile's mainboard needs to detect the voltage on the right side of S3 / S4 to determine if the power supply is normal. Referring to standard GB-T18487.1B.4.2 (after the vehicle interface is fully connected and the electronic lock is engaged, S3 and S4 are closed to conduct the low-voltage auxiliary power supply circuit, initiating the handshake startup phase and periodically sending communication handshake messages), this standard essentially means that CAN communication occurs after the charging gun is fully connected and the charging pile has begun supplying auxiliary power to the vehicle's BMS. The low-voltage power supply and BMS auxiliary power supply within the charging pile's mainboard are inherently isolated from each other. Figure 3 While the auxiliary power supply voltage is being detected by the right side of S3 / S4, an LDO outputs digital isolation and CAN chip power supply voltage, thus replacing the function of the isolated power supply. (If the BMS auxiliary power supply voltage VFY acquisition circuit also uses a separate isolated power supply, it can also be used as a substitute.) One important point to note is... (Refer to...) Figure 2 In the digitally isolated power supply, the left power supply is VCC3V3 and the right power supply is 5VCAN. If the VFY (BMS auxiliary power supply) to LDO scheme is adopted, the timing of VCC3V3 and 5VCAN startup needs to be controlled. A control circuit needs to be added at the VCC3V3 position to control the power supply of VCC3V3 while closing S3 / S4. The change of the timing of the two power supplies of digital isolation will affect its output status.

[0049] Both power modules and isolated power modules can power the CAN circuit. Currently, the conventional method uses isolated power modules, which are the main technical component of this approach. In charging pile design, considering the electrical environment differences and safety risks between the charging pile and the electric vehicle, isolation is added between the charging pile motherboard and the BMS for information feedback and communication. CAN, as the primary communication method between the charging pile and the electric vehicle, is typically isolated using ordinary optocouplers or digital isolation chips. This requires a power supply isolated from the charging pile motherboard to power these isolated components. Conventional solutions use isolated power modules or separate isolated power supplies, which are significantly more expensive than this circuit design.

[0050] The main solution of this utility model is to replace the isolated power supply with a simple LDO, thereby significantly reducing the cost of the entire CAN circuit.

[0051] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

[0052] Furthermore, it should be noted that if any directional indication (such as up, down, left, right, front, back, etc.) is involved in the embodiments of this utility model, the directional indication is only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0053] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, in the embodiments of this utility model, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A charging pile motherboard isolated power supply circuit, characterized in that, include: Isolated power supply module, digital isolation module, CAN transceiver module, MCU control module, peripheral circuit module; The MCU control module is connected to the digital isolation module, the digital isolation module is connected to the isolation power supply module and the CAN transceiver module, the isolation power supply module is connected to the CAN transceiver module, and the CAN transceiver module is connected to the peripheral circuit module. In the isolated power supply module, the VIN terminal of the isolated power supply chip U4 is connected to the inductor L1 and the capacitor C4. The other end of the inductor L1 is connected to the 5V voltage source and the capacitor C3. The other end of the capacitor C4 is connected to the GND terminal of the isolated power supply chip U4. Both are grounded at the same time, and the other end of the capacitor C3 is grounded. The GND terminal of the isolation power chip U4 is connected to capacitor C7, the other end of capacitor C7 is connected to capacitor C8, and the other end of capacitor C8 is connected to the -V0 terminal of the digital isolation chip U4. The +V0 terminal of the isolation power supply chip U4 is connected to inductor L2 and capacitor C5. The other end of inductor L2 is connected to capacitor C6, and the other end of capacitor C5 is connected to the -V0 terminal of isolation power supply U4. Resistors R8 and R9 are connected in parallel across capacitor C6.

2. The isolated power supply circuit for the charging pile motherboard as described in claim 1, characterized in that, The digital isolation module includes: The OUTB terminal of digital isolation chip U1 is connected to resistor R2, and the other end of resistor R2 serves as the CAN1_RX port; the INA terminal of digital isolation chip U1 is connected to resistor R4, and the other end of resistor R4 serves as the CAN1_TX terminal; the INB terminal of digital isolation chip U1 is connected to resistor R3, and the other end of resistor R3 is connected to the CAN transceiver module; the OUTA terminal of digital isolation chip U1 is connected to resistor R5, and the other end of resistor R5 is connected to the CAN transceiver module.

3. The isolated power supply circuit for the charging pile motherboard as described in claim 2, characterized in that, The CAN transceiver module includes: the RXD port of CAN transceiver U2 is connected to the resistor R3 of the peripheral circuit module; the TXD terminal of CAN transceiver U2 is connected to the resistor R5 of the peripheral circuit module; the STB terminal of CAN transceiver U2 is connected to the resistor R1, and the resistor R1 serves as the QCAN1 port connected to the isolated power supply module. The CANH terminal of CAN transceiver U2 is connected to port 3 of common mode choke U3, and the CANL terminal of CAN transceiver U2 is connected to port 4 of common mode choke U3. The NC terminal of CAN transceiver U2 is connected to resistor R9. The other end of resistor R9 is connected to resistor R6, resistor R7 and capacitor C11. The other end of resistor R6 is connected to port 1 of common mode choke U3. The other end of resistor R7 is connected to port 2 of common mode choke U3. The other end of capacitor C11 serves as QCAN1 port. Capacitor C1 is connected to port 1 of common mode choke U3, and the other end is connected to capacitor C2. The other end of capacitor C2 is connected to port 2 of common mode choke U3. The two ends of the voltage suppression diode Z1 are connected to port 1 and port 2 of the common-mode choke U3, respectively; One end of voltage suppression diode Z2 is connected to voltage suppression diode Z3, and the other end is connected to port 1 of common mode choke U3. The other end of voltage suppression diode Z3 is connected to port 2 of common mode choke U3.

4. The isolated power supply circuit for the charging pile motherboard as described in claim 1, characterized in that, The isolated power supply module also includes: capacitor C11 connected to the VIN terminal of LDO power chip U5, capacitor C11 connected to the GND terminal of LDO power chip U5, and capacitor C10 connected in parallel across capacitor C11; The VOUT terminal of the LDO power chip U5 is connected to capacitor C12, and the other end of capacitor C12 is connected to the GND terminal of the LDO power chip U5. Capacitor C13 is connected in parallel across capacitor C12, with one end serving as the 5VCAN1 port and the other end serving as the GCAN1 port.

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