CAN bus voltage stabilizing circuit for 12V / 24V / 48V system

Abstract

The utility model relates to the field of electrical engineering and electronic engineering, and discloses a CAN bus voltage stabilizing circuit for a 12V / 24V / 48V system, the CAN bus voltage stabilizing circuit comprises a first output end and a second output end, a pressure relief unit is arranged between the first output end and the second output end, the pressure relief unit is provided with a first connecting end, a second connecting end and a third connecting end, the first connecting end is connected with the first output end, the second connecting end is connected with the second output end, and the third connecting end is grounded; the voltage relief unit further comprises a first voltage-regulator tube, a second voltage-regulator tube and a voltage-regulator capacitor, the voltage-regulator capacitor is provided with a first terminal and a second terminal, the positive electrode end of the first voltage-regulator tube is connected with the first connecting end, the negative electrode end of the first voltage-regulator tube is connected with the first terminal, the positive electrode end of the second voltage-regulator tube is connected with the second connecting end, and the negative electrode end of the second voltage-regulator tube is connected with the first terminal. And the second terminal is connected with the third connecting end. Static electricity is absorbed through the voltage stabilizing capacitor in the voltage relief unit, overvoltage protection is provided for the bus, the voltage of the output end is stabilized, and it is ensured that the voltage on the bus is within the specified range.

Description

Technical Field

[0001] The present application relates to the fields of electrical engineering and electronic engineering, and in particular to a CAN bus voltage stabilization circuit for a 12V / 24V / 48V system. Background Art

[0002] CAN bus (Controller Area Network) is a serial communication protocol widely used in automobiles, industrial control and other fields. It allows multiple microcontrollers or devices to communicate on a network to achieve real-time data transmission and control.

[0003] The CAN bus voltage regulator circuit refers to the circuit used in the CAN bus communication system. Its main function is to ensure the voltage stability on the CAN bus. The CAN bus standard specifies the voltage range on the communication line to ensure reliable communication under different working conditions. In applications such as automobiles, environmental conditions may change continuously, such as engine starting, charging system changes, etc., so a voltage regulator circuit is needed to ensure that the voltage on the CAN bus is within the specified range. Utility Model Content

[0004] In order to ensure that the voltage on the CAN bus is within a specified range, the present application provides a CAN bus voltage stabilization circuit for a 12V / 24V / 48V system.

[0005] The present application provides a CAN bus voltage stabilizing circuit for a 12V / 24V / 48V system, which adopts the following technical solution:

[0006] A CAN bus voltage stabilizing circuit for a 12V / 24V / 48V system, comprising a first output terminal CAN_H and a second output terminal CAN_L, wherein the first output terminal CAN_H and the second output terminal CAN_L are used to connect an external device, a pressure relief unit is provided between the first output terminal CAN_H and the second output terminal CAN_L, the pressure relief unit is provided with a first connection terminal, a second connection terminal and a third connection terminal, the first connection terminal is connected to the first output terminal CAN_H, the second connection terminal is connected to the second output terminal CAN_L, and the third connection terminal is grounded, and the pressure relief unit is used to release the excess voltage on the first output terminal CAN_H or the second output terminal CAN_L to the ground when the voltage value on the first output terminal CAN_H or the second output terminal CAN_L exceeds a preset voltage value;

[0007] The pressure relief unit includes a first voltage-stabilizing tube D1, a second voltage-stabilizing tube D2 and a voltage-stabilizing capacitor C3. The first voltage-stabilizing tube D1 and the second voltage-stabilizing tube D2 each include a positive tube and a negative terminal. The voltage-stabilizing capacitor C3 is provided with a first terminal and a second terminal. The positive terminal of the first voltage-stabilizing tube D1 is connected to the first connecting terminal, and the negative terminal is connected to the first terminal. The positive terminal of the second voltage-stabilizing tube D2 is connected to the second connecting terminal, and the negative terminal is connected to the first terminal. The second terminal is connected to the third connecting terminal.

[0008] By adopting the above technical solution, the pressure relief unit is directly connected to the output end, and can quickly respond to the situation where the voltage exceeds the preset value, reducing the risk of overvoltage causing damage to the system. Specifically, when high voltage appears on the first output terminal CAN_H or the second output terminal CAN_L, the pressure relief unit can release the excess voltage to the ground, provide overvoltage protection, stabilize the voltage on the first output terminal CAN_H or the second output terminal CAN_L, prevent external devices from being damaged, and ensure that the voltage on the CAN bus is within the specified range.

[0009] Specifically, the static electricity generated by the first Zener diode D1 and the second Zener diode D2 can be absorbed by the voltage-stabilizing capacitor C3. That is to say, when the circuit is affected by a voltage peak or spike and causes overvoltage, the circuit may exceed the maximum reverse operating voltage of the Zener diode to damage the Zener diode. At this time, the voltage-stabilizing capacitor C3 can absorb the static electricity generated by the Zener diode and reduce the probability of damage to the Zener diode due to overvoltage.

[0010] Exemplarily, the pressure relief unit includes a first voltage regulator tube D1 and a second voltage regulator tube D2, the first voltage regulator tube D1 and the second voltage regulator tube D2 both include a positive tube and a negative terminal, the positive terminal of the first voltage regulator tube D1 is connected to the first connection terminal, and the negative terminal is connected to the third connection terminal, the positive terminal of the second voltage regulator tube D2 is connected to the second connection terminal, and the negative terminal is connected to the third connection terminal.

[0011] By adopting the above technical solution, two voltage regulators, namely the first voltage regulator D1 and the second voltage regulator D2, can be used to respectively provide overvoltage protection for the first output terminal CAN_H and the second output terminal CAN_L. When a high voltage appears on the first output terminal CAN_H, the first voltage regulator D1 is turned on, and the first voltage regulator D1 releases excess voltage to the ground, providing overvoltage protection for the first output terminal CAN_H. When a high voltage appears on the second output terminal CAN_L, the second voltage regulator D2 is turned on, and the second voltage regulator D2 releases excess voltage to the ground, providing overvoltage protection for the second output terminal CAN_L.

[0012] Specifically, the voltage stabilizing capacitor C3 has a certain ability to absorb or store charge, and it responds to voltage changes faster than other components. The voltage stabilizing capacitor C3 is added to the pressure relief unit. When the system is subjected to a voltage peak or spike, the voltage stabilizing capacitor C3 can absorb part of the overvoltage and prevent it from being transmitted to the voltage stabilizing tube, thereby reducing the burden on the voltage stabilizing tube and extending its life.

[0013] In short, the voltage-stabilizing capacitor C3 can act as a voltage buffer to absorb overvoltage and protect the voltage-stabilizing tube from potential voltage peaks or spikes in the circuit, thereby extending the life of the pressure relief unit.

[0014] Exemplarily, the first voltage regulator tube D1 and the second voltage regulator tube D2 are both TVS tubes.

[0015] By adopting the above technical solutions, the TVS tube responds quickly and can start working immediately when a voltage transient occurs, which is crucial for quickly suppressing excessive voltage. In addition, TVS tubes are usually designed to absorb a large amount of energy. They can quickly guide the overvoltage energy to the ground to prevent it from propagating to external devices connected to the CAN bus. TVS tubes are reusable and they are able to maintain their protection performance even after multiple overvoltage events. This allows the circuit to continue to operate normally after the transient voltage problem is resolved.

[0016] Furthermore, the TVS tube can also transfer static electricity to the ground when static electricity is transmitted to the first output terminal CAN_H or the second output terminal CAN_L.

[0017] Exemplarily, it also includes a first input terminal CANH, a second input terminal CANL and a common-mode suppression unit, wherein the first input terminal CANH and the second input terminal CANL are used to connect to the output terminal of the CAN transceiver chip, the common-mode suppression unit includes a common-mode suppression inductor L1, a first common-mode suppression resistor R1 and a second common-mode suppression resistor R2, the common-mode suppression inductor L1 includes a first connection terminal of phase A, a second connection terminal of phase A, a first connection terminal of phase B and a second connection terminal of phase B, the first connection terminal of phase A is connected to the first input terminal CANH, the second connection terminal of phase A is connected to the first output terminal CAN_H, the first connection terminal of phase B is connected to the second input terminal CANL, the second connection terminal of phase B is connected to the second output terminal CAN_L, one end of the first common-mode suppression resistor R1 is connected to the first connection terminal of phase A, and the other end is connected to the second connection terminal of phase A, one end of the second common-mode suppression resistor R2 is connected to the first connection terminal of phase B, and the other end is connected to the second connection terminal of phase B.

[0018] By adopting the above technical solution, the common mode suppression unit can filter out the high-frequency noise outside the bus and the common mode noise generated by the CAN transceiver due to signal asymmetry without affecting the transmission quality of the CAN differential signal, thereby improving the anti-interference ability of the system and reducing the EMI of the system.

[0019] Exemplarily, a filtering unit is also included, which includes a first filter resistor R3, a second filter resistor R4 and a first filter capacitor C1, the first filter capacitor C1 includes a first terminal and a second terminal, one end of the first filter resistor R3 is connected to the first output terminal CAN_H, and the other end is connected to the first terminal of the first filter capacitor C1, one end of the second filter resistor R4 is connected to the second output terminal CAN_L, and the other end is connected to the first terminal of the first filter capacitor C1, and the second terminal of the first filter capacitor C1 is grounded.

[0020] By adopting the above technical solution, the filtering unit helps to improve the signal consistency between the two bus lines of the first input terminal CANH-the first output terminal CAN_H and the second input terminal CANL-the second output terminal CAN_L, reduce EMI, and at the same time can lead the common mode interference here to the ground, reducing interference to the bus.

[0021] Exemplarily, the pressure relief unit further includes a second filter capacitor C2, a first output point is further provided between the first voltage regulator tube D1 and the first output terminal CAN_H, one end of the second filter capacitor C2 is connected to the first output point, and the other end is grounded.

[0022] By adopting the above technical solution, interference can be filtered out and transient overshoot of the automobile CAN bus can be reduced.

[0023] Exemplarily, the pressure relief unit further includes a third filter capacitor C4, a second output point is further provided between the second voltage regulator tube D2 and the second output terminal CAN_L, one end of the third filter capacitor C4 is connected to the second output point, and the other end is grounded.

[0024] By adopting the above technical solution, interference can be filtered out and transient overshoot of the automobile CAN bus can be reduced.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. By directly connecting the pressure relief unit to the output terminal, it can respond quickly to the situation where the voltage exceeds the preset value, reducing the risk of overvoltage causing damage to the system. Specifically, when high voltage appears on the first output terminal CAN_H or the second output terminal CAN_L, the pressure relief unit can release the excess voltage to the ground, provide overvoltage protection, stabilize the voltage on the first output terminal CAN_H or the second output terminal CAN_L, prevent external devices from being damaged, and ensure that the voltage on the CAN bus is within the specified range;

[0027] By setting the voltage stabilizing capacitor C3, the first voltage stabilizing tube D1 and the second voltage stabilizing tube D2 can be protected. Specifically, when the system is subjected to a voltage peak or spike, the voltage stabilizing capacitor C3 can absorb a portion of the overvoltage and prevent it from being transmitted to the voltage stabilizing tube, thereby reducing the burden of the voltage stabilizing tube and extending the life of the voltage stabilizing tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The invention is a circuit diagram of a CAN bus voltage stabilizing circuit for a 12V / 24V / 48V system.

[0029] Description of reference numerals:

[0030] 1. Pressure relief unit; 2. Common mode suppression unit; 3. Filter unit. DETAILED DESCRIPTION

[0031] The present application is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] 24V / 48V system refers to the 24V voltage system or 48V voltage system used by the battery of an electric vehicle. Among them, the operating voltage of the 24V system is 16-32V, and the operating voltage of the 48V system is 36-60V. Due to the high operating voltage of the 24V system and the 48V system, especially the operating voltage of the 48V system, the voltage withstand value requirements of the voltage regulator tube on the CAN circuit are also increased. If a short circuit occurs or other components bring high voltage, it is very likely to directly destroy the voltage regulator tube. The CAN bus voltage regulator circuit for the 12V / 24V / 48V system provided by the embodiment of the present application can effectively reduce the probability of damage to the voltage regulator tube. When the CAN bus voltage regulator circuit is applied in different voltage systems, it is only necessary that the voltage withstand values ​​of the chips and components connected thereto meet the corresponding voltage conditions. It should be understood that under the above conditions, the CAN bus voltage regulator circuit for the 12V / 24V / 48V system proposed in the embodiment of the present application can also be applied to systems in other voltage ranges when the voltage withstand values ​​of the chips and components connected thereto meet the voltage conditions.

[0033] The present application embodiment discloses a CAN bus voltage stabilizing circuit for a 12V / 24V / 48V system. Figure 1 A CAN bus voltage stabilizing circuit for a 12V / 24V / 48V system includes a first output terminal CAN_H and a second output terminal CAN_L. The first output terminal CAN_H and the second output terminal CAN_L are used to connect an external device, and a pressure relief unit 1 is used to release the excess voltage on the first output terminal CAN_H or the second output terminal CAN_L to the ground when the voltage value on the first output terminal CAN_H or the second output terminal CAN_L exceeds a preset voltage value.

[0034] Reference Figure 1 A pressure relief unit 1 is provided between the first output terminal CAN_H and the second output terminal CAN_L. The pressure relief unit 1 is provided with a first connection terminal, a second connection terminal and a third connection terminal. The first connection terminal is connected to the first output terminal CAN_H, the second connection terminal is connected to the second output terminal CAN_L, and the third connection terminal is grounded.

[0035] Specifically, in different embodiments, the pressure relief unit 1 can release the excess voltage on the first output terminal CAN_H and the second output terminal CAN_L to the ground by setting different components. Embodiment 1 of the pressure relief unit 1 of the present application discloses a structure of the pressure relief unit 1. The pressure relief unit 1 includes a first voltage regulator tube D1 and a second voltage regulator tube D2. The first voltage regulator tube D1 and the second voltage regulator tube D2 both include a positive tube and a negative terminal. The positive terminal of the first voltage regulator tube D1 is connected to the first connection terminal, and the negative terminal is connected to the third connection terminal. The positive terminal of the second voltage regulator tube D2 is connected to the second connection terminal, and the negative terminal is connected to the third connection terminal.

[0036] In the first embodiment, the first voltage regulator tube D1 and the second voltage regulator tube D2 in the pressure relief unit 1 are key components for maintaining the voltage at the output end within a stable range. However, sometimes the circuit may be affected by voltage peaks or spikes, resulting in overvoltage, and the overvoltage may exceed the maximum reverse operating voltage of the voltage regulator tube, causing damage to the voltage regulator tube. Therefore, the second embodiment of the pressure relief unit 1 of the present application discloses a structure of a pressure relief unit 1, the pressure relief unit 1 includes a first voltage regulator tube D1, a second voltage regulator tube D2 and a voltage regulator capacitor C3, the first voltage regulator tube D1 and the second voltage regulator tube D2 both include a positive tube and a negative terminal, the voltage regulator capacitor C3 is provided with a first terminal and a second terminal, the positive terminal of the first voltage regulator tube D1 is connected to the first connection terminal, and the negative terminal is connected to the first terminal, the positive terminal of the second voltage regulator tube D2 is connected to the second connection terminal, the negative terminal is connected to the first terminal, and the second terminal is connected to the third connection terminal.

[0037] The voltage stabilizing capacitor C3 has a certain ability to absorb or store charge, and responds to voltage changes faster than other components. In the present application, the voltage stabilizing capacitor C3 can act as a voltage buffer, absorb overvoltage, and protect the voltage stabilizing tube from potential voltage peaks or spikes in the circuit, thereby extending the life of the voltage stabilizing tube. Specifically, when the system is subjected to a voltage peak or spike, the voltage stabilizing capacitor C3 can absorb a portion of the overvoltage and prevent it from being transmitted to the voltage stabilizing tube, thereby reducing the burden on the voltage stabilizing tube and extending its life.

[0038] Furthermore, the first voltage-stabilizing tube D1 and the second voltage-stabilizing tube D2 in the implementation example 1 and the second implementation example 2 of the pressure relief unit 1 of the present application are both TVS tubes. The response speed of the TVS tube is very fast, and it can start working immediately when the voltage transient occurs. Moreover, TVS tubes are usually designed to absorb a large amount of energy. They can quickly guide the overvoltage energy to the ground to prevent it from propagating to external devices connected to the CAN bus. The first voltage-stabilizing tube D1 and the second voltage-stabilizing tube D2 in the implementation example 1 and the second implementation example 2 of the pressure relief unit 1 of the present application both use TVS tubes, and static electricity can also be transmitted to the ground when static electricity is transmitted to the first output terminal CAN_H or the second output terminal CAN_L.

[0039] In the embodiment 1 and the embodiment 2 of the pressure relief unit 1 of the present application, a second filter capacitor C2 and a third filter capacitor C4 are also provided. Specifically, a first output point is provided between the first voltage regulator tube D1 and the first output terminal CAN_H, one end of the second filter capacitor C2 is connected to the first output point, and the other end is grounded. A second output point is provided between the second voltage regulator tube D2 and the second output terminal CAN_L, one end of the third filter capacitor C4 is connected to the second output point, and the other end is grounded. Such a setting can filter out interference for the pressure relief unit 1 and reduce transient overshoot of the automobile CAN bus.

[0040] Continue to refer Figure 1 The CAN bus voltage stabilizing circuit for 12V / 24V / 48V system disclosed in the embodiment of the present application also includes a first input terminal CANH, a second input terminal CANL and a common mode suppression unit 2. The common mode suppression unit 2 is used to filter out the high frequency noise outside the bus and the common mode noise generated by the CAN transceiver due to signal asymmetry, so as to reduce the influence of the common mode noise on the transmission quality of the CAN differential signal, improve the anti-interference ability of the system and reduce the effect of the system EMI. The first input terminal CANH and the second input terminal CANL are used to connect to the output terminal of the CAN transceiver chip.

[0041] The common mode suppression unit 2 includes a common mode suppression inductor L1, a first common mode suppression resistor R1 and a second common mode suppression resistor R2. The common mode suppression inductor L1 includes a first connection end of phase A, a second connection end of phase A, a first connection end of phase B and a second connection end of phase B. The first connection end of phase A is connected to the first input end CANH, the second connection end of phase A is connected to the first output end CAN_H, the first connection end of phase B is connected to the second input end CANL, and the second connection end of phase B is connected to the second output end CAN_L. One end of the first common mode suppression resistor R1 is connected to the first connection end of phase A, and the other end is connected to the second connection end of phase A. One end of the second common mode suppression resistor R2 is connected to the first connection end of phase B, and the other end is connected to the second connection end of phase B.

[0042] Continue to refer Figure 1 The CAN bus voltage stabilizing circuit for 12V / 24V / 48V system disclosed in the embodiment of the present application further includes a filter unit 3. The filter unit 3 is used to make the signals between the first input terminal CANH-first output terminal CAN_H and the second input terminal CANL-second output terminal CAN_L consistent, reduce EMI, and at the same time, lead the common mode interference here to the ground to reduce interference to the bus.

[0043] The filter unit 3 includes a first filter resistor R3, a second filter resistor R4 and a first filter capacitor C1. The first filter capacitor C1 includes a first terminal and a second terminal, one end of the first filter resistor R3 is connected to the first output terminal CAN_H, and the other end is connected to the first terminal of the first filter capacitor C1, one end of the second filter resistor R4 is connected to the second output terminal CAN_L, and the other end is connected to the first terminal of the first filter capacitor C1, and the second terminal of the filter capacitor is grounded.

[0044] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A CAN bus voltage stabilizing circuit for 12V / 24V / 48V system, characterized in that: The device comprises a first output terminal CAN_H and a second output terminal CAN_L, wherein the first output terminal CAN_H and the second output terminal CAN_L are used to connect to an external device, a pressure relief unit (1) is arranged between the first output terminal CAN_H and the second output terminal CAN_L, the pressure relief unit (1) is provided with a first connection terminal, a second connection terminal and a third connection terminal, the first connection terminal is connected to the first output terminal CAN_H, the second connection terminal is connected to the second output terminal CAN_L, and the third connection terminal is grounded, and the pressure relief unit (1) is used to release the excess voltage on the first output terminal CAN_H or the second output terminal CAN_L to the ground when the voltage value on the first output terminal CAN_H or the second output terminal CAN_L exceeds a preset voltage value; The pressure relief unit (1) further comprises a first voltage regulator tube D1, a second voltage regulator tube D2 and a voltage regulator capacitor C3, wherein the first voltage regulator tube D1 and the second voltage regulator tube D2 both comprise a positive electrode tube and a negative electrode terminal, and the voltage regulator capacitor C3 is provided with a first terminal and a second terminal, wherein the positive electrode terminal of the first voltage regulator tube D1 is connected to the first connection terminal, and the negative electrode terminal is connected to the first terminal, the positive electrode terminal of the second voltage regulator tube D2 is connected to the second connection terminal, and the negative electrode terminal is connected to the first terminal, and the second terminal is connected to the third connection terminal.

2. The CAN bus voltage stabilizing circuit for 12V / 24V / 48V system according to claim 1, characterized in that: The first voltage regulator tube D1 and the second voltage regulator tube D2 are both TVS tubes.

3. The CAN bus voltage stabilizing circuit for 12V / 24V / 48V system according to claim 1, characterized in that: The invention also comprises a first input terminal CANH, a second input terminal CANL and a common mode suppression unit (2), wherein the first input terminal CANH and the second input terminal CANL are used to be connected to the output terminal of the CAN transceiver chip, the common mode suppression unit (2) comprises a common mode suppression inductor L1, a first common mode suppression resistor R1 and a second common mode suppression resistor R2, the common mode suppression inductor L1 comprises an A phase first connection terminal, an A phase second connection terminal, a B phase first connection terminal and a B phase second connection terminal, the A phase first connection terminal is connected to the first input terminal CANH, the A phase second connection terminal is connected to the first output terminal CAN_H, the B phase first connection terminal is connected to the second input terminal CANL, the B phase second connection terminal is connected to the second output terminal CAN_L, one end of the first common mode suppression resistor R1 is connected to the A phase first connection terminal, and the other end is connected to the A phase second connection terminal, one end of the second common mode suppression resistor R2 is connected to the B phase first connection terminal, and the other end is connected to the B phase second connection terminal.

4. The CAN bus voltage stabilizing circuit for 12V / 24V / 48V system according to claim 3, characterized in that: The device further comprises a filtering unit (3), wherein the filtering unit (3) is located between the common-mode suppression unit (2) and the pressure relief unit (1), and the filtering unit (3) comprises a first filtering resistor R3, a second filtering resistor R4 and a first filtering capacitor C1, wherein the first filtering capacitor C1 comprises a first terminal and a second terminal, wherein one end of the first filtering resistor R3 is connected to the first output terminal CAN_H, and the other end is connected to the first terminal of the first filtering capacitor C1, wherein one end of the second filtering resistor R4 is connected to the second output terminal CAN_L, and the other end is connected to the first terminal of the first filtering capacitor C1, and the second terminal of the first filtering capacitor C1 is grounded.

5. The CAN bus voltage stabilizing circuit for 12V / 24V / 48V system according to claim 1, characterized in that: The pressure relief unit (1) further comprises a second filter capacitor C2, a first output point is further provided between the first voltage regulator tube D1 and the first output end CAN_H, one end of the second filter capacitor C2 is connected to the first output point, and the other end is grounded.

6. The CAN bus voltage stabilizing circuit for 12V / 24V / 48V system according to claim 1, characterized in that: The pressure relief unit (1) further comprises a third filter capacitor C4, a second output point is further provided between the second voltage regulator tube D2 and the second output end CAN_L, one end of the third filter capacitor C4 is connected to the second output point, and the other end is grounded.

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