Unibus communication circuit applied to automobile

Through the voltage divider circuit and MOS tube design, the problems of low voltage withstandability and high cost in the automotive bus communication circuit are solved, and voltage stability and cost reduction in high voltage environments are achieved.

CN120301728APending Publication Date: 2025-07-11NANJING WEIFU JINNING
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Patent Information

Application Number
CN202510446328.4
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-04-10
Publication Date
2025-07-11

AI Technical Summary

Technical Problem

In existing automotive bus communication circuits, the port voltage resistance is low and the cost is high, especially in electrical environments above 60V, which requires additional protection, resulting in an increase in costs.

Method used

The voltage divider circuit and MOS tube design are used, and the first transistor and AND gate circuit are converted into 5V logic levels, and the MOS tube is used to enhance the surge resistance. The signal output circuit adopts a split solution, using materials widely used on the market.

Benefits of technology

It realizes voltage stability and signal reliability in high voltage environments, reduces overall costs, and meets harsh electrical environment requirements.

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Abstract

The invention relates to a unibus communication circuit applied to an automobile, which comprises a communication receiving circuit and a communication transmitting circuit, the input end of the communication receiving circuit and the output end of the communication transmitting circuit are both connected with an input / output port, and the output end of the communication receiving circuit is connected with the input port of an MCU (Microprogrammed Control Unit). The input end of the communication transmitting circuit is connected with the output port of the MCU; the voltage division circuit is adopted to divide the input voltage, the input voltage can be more stably matched with a switching circuit of the first triode Q2 to be converted into a 5V logic level, the voltage is more stable, and secondly, the signal output circuit adopts an MOS tube, so that the signal output circuit has higher anti-surge capacity, and the more harsh field electrical environment requirement is met. According to the invention, a split circuit scheme is adopted, materials which are delivered on a large scale and are widely applied in the market are selected, and compared with an integrated chip scheme, the overall cost has obvious advantages.
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Description

Technical Field

[0001] The present invention relates to the technical field of automotive communication, and particularly to an automotive single-bus communication circuit. Background Art

[0002] In existing automotive systems, communication between systems generally uses CAN, LIN, etc. Generally, CAN communication requires the MCU to have a CAN controller, and a CAN transceiver is also required outside the MCU for level conversion. Similarly, LIN communication generally also requires a LIN transceiver for level conversion, and the price is also high. At the same time, whether it is a CAN transceiver or a LIN transceiver, due to the chip integration solution, the withstand voltage capacity of the port is generally below 60V. If the interface has an electrical environment higher than 60V, an additional protection circuit is required for the port, which leads to an increase in cost. Summary of the Invention

[0003] Therefore, the present invention provides an automotive single-bus communication circuit to solve the problems of low port withstand voltage capacity and high cost.

[0004] The technical solution of the present invention is as follows: An automotive single-bus communication circuit includes a communication receiving circuit and a communication transmitting circuit. The input end of the communication receiving circuit and the output end of the communication transmitting circuit are both connected to an input / output port. The output end of the communication receiving circuit is connected to the input port of the MCU, and the input end of the communication transmitting circuit is connected to the output port of the MCU; The communication receiving circuit includes a first resistor R1, a first capacitor C1, a second resistor R2, a third resistor R3, a first triode Q2, a first AND gate U1, and a fourth resistor R4. One end of the first resistor R1 is connected to the input / output port, and the other end of the first resistor R1 is connected to one end of the first capacitor C1, one end of the second resistor R2, and the base of the first triode Q2. The other end of the first capacitor C1 and the other end of the second resistor R2 are grounded. The emitter of the first triode Q2 is grounded, and the collector of the first triode Q2 is connected to both input ends of the first AND gate U1 and one end of the third resistor R3. The other end of the third resistor R3 is connected to the supply voltage V cc , and the output end of the first AND gate U1 is connected to the other end of the fourth resistor R4, which is connected to the input port of the MCU.

[0005] Further, one of the input ends of the first AND gate U1 is connected to one end of a second capacitor C2, and the other end of the second capacitor C2 is grounded.

[0006] Further, the first triode Q2 is a switching-type NPN transistor.

[0007] Further, the supply voltage is V ccThe voltage is 5V.

[0008] Further, the communication transmitting circuit includes a first pre-driver chip U2, a first MOS transistor Q1, and a fifth resistor R5. The input end of the first pre-driver chip U2 is connected to the output port of the MCU, the output end of the first pre-driver chip U2 is connected to the gate of the first MOS transistor Q1, the source of the first MOS transistor Q1 is connected to the input / output port and one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the power supply V bat .

[0009] Further, the first MOS transistor Q1 is an NMOS transistor.

[0010] Further, the first pre-driver U2 is a MOSFET pre-driver chip.

[0011] Further, the power supply V bat is the power supply.

[0012] The beneficial effects of the present invention are as follows: The present invention uses a voltage-dividing circuit to divide the input voltage, which can more stably cooperate with the switching circuit of the first triode Q2 to convert it into a 5V logic level, making the voltage more stable. Secondly, the signal output circuit uses MOS transistors, which have stronger surge resistance and meet the requirements of harsher on-site electrical environments. Secondly, the present invention adopts a split-circuit scheme, and the selected materials are all those with large quantities of shipments and wide applications in the market. The overall cost has obvious advantages compared with the integrated chip scheme. Description of the Drawings

[0013] Figure 1 is the circuit diagram of the present invention. Detailed Embodiments

[0014] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0015] In the technical solution of the present invention, Figure 1 is a structural schematic diagram provided according to a specific circuit of an automotive single-bus communication circuit of the present invention, as Figure 1As shown in the figure, the present invention includes a communication receiving circuit and a communication transmitting circuit. The input end of the communication receiving circuit and the output end of the communication transmitting circuit are both connected to an input / output port. The output end of the communication receiving circuit is connected to the input port of the MCU, and the input end of the communication transmitting circuit is connected to the output port of the MCU.

[0016] The communication receiving circuit includes a first resistor R1, a first capacitor C1, a second resistor R2, a third resistor R3, a first triode Q2, a first AND gate U1, and a fourth resistor R4. One end of the first resistor R1 is connected to the input / output port. The other end of the first resistor R1 is connected to one end of the first capacitor C1, one end of the second resistor R2, and the base of the first triode Q2. The other end of the first capacitor C1 and the other end of the second resistor R2 are grounded. The emitter of the first triode Q2 is grounded. The collector of the first triode Q2 is connected to the two input ends of the first AND gate U1 and one end of the third resistor R3. The other end of the third resistor R3 is connected to the supply voltage V cc , and the output end of the first AND gate U1 is connected to the other end of the fourth resistor R4, which is connected to the input port of the MCU.

[0017] Among them, the input / output port COM_PORT is connected to other systems inside the vehicle, and the input port of the MCU is MCU_PORT1.

[0018] In an embodiment of the present invention, one of the input ends of the first AND gate U1 is connected to one end of a second capacitor C2, and the other end of the second capacitor C2 is grounded.

[0019] In an embodiment of the present invention, the first triode Q2 is a switching NPN transistor.

[0020] In an embodiment of the present invention, the supply voltage is V cc is 5V voltage.

[0021] In an embodiment of the present invention, the communication transmitting circuit includes a first pre-driver chip U2, a first MOS transistor Q1, and a fifth resistor R5. The input end of the first pre-driver chip U2 is connected to the output port of the MCU. The output end of the first pre-driver chip U2 is connected to the gate of the first MOS transistor Q1. The source of the first MOS transistor Q1 is connected to the input / output port and one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to the power supply V bat .

[0022] In an embodiment of the present invention, the first MOS transistor Q1 is an NMOS transistor.

[0023] In one embodiment of the present invention, the first pre-driver U2 is a MOSFET pre-driver chip.

[0024] In one embodiment of the present invention, the power supply V bat is the power supply.

[0025] The present invention provides an application for the design of a single-bus communication circuit for automotive parts, and the specific principle is as follows: Communication receiving circuit: When other systems inside the vehicle send a communication signal to the communication receiving circuit, the signal is divided by the first resistor R1 and the second resistor R2, and cooperates with the first triode Q2 switching circuit to be converted into a 5V logic level. The logic level is output to the MCU after logical conversion by the first AND gate U1. The MCU analyzes the protocol content through a pre-established communication protocol and cooperates. The U1 also plays a role in signal filtering.

[0026] Communication sending circuit: The MCU encodes according to a pre-established communication protocol and outputs a signal to the first pre-driver U2 through a pre-established protocol frame. The first pre-driver U2 outputs to drive the MOSFET to perform level conversion and output to each system inside the vehicle. The first pre-driver U2 plays a role in enhancing the driving ability.

[0027] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. An automotive single - wire communication circuit, characterized in that, Including: A communication receiving circuit and a communication transmitting circuit, wherein the input end of the communication receiving circuit and the output end of the communication transmitting circuit are both connected to an input / output port, the output end of the communication receiving circuit is connected to the input port of an MCU, and the input end of the communication transmitting circuit is connected to the output port of the MCU; The communication receiving circuit includes: a first resistor R1, a first capacitor C1, a second resistor R2, a third resistor R3, a first triode Q2, a first AND gate U1, and a fourth resistor R4. One end of the first resistor R1 is connected to the input / output port. The other end of the first resistor R1 is connected to one end of the first capacitor C1, one end of the second resistor R2, and the base of the first triode Q2. The other end of the first capacitor C1 and the other end of the second resistor R2 are grounded. The emitter of the first triode Q2 is grounded. The collector of the first triode Q2 is connected to two input terminals of the first AND gate U1 and one end of the third resistor R3. The other end of the third resistor R3 is connected to the power supply voltage V cc . The output terminal of the first AND gate U1 is connected to the other end of the fourth resistor R4, which is connected to the input port of the MCU.

2. The automotive single-bus communication circuit according to claim 1, wherein One input end of the first AND gate U1 is connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is grounded.

3. The automotive single-bus communication circuit according to claim 1, wherein The first triode Q2 is a switching-type NPN transistor.

4. The automotive single-bus communication circuit according to claim 1, characterized in that, The supply voltage is V cc It is a 5V voltage.

5. The automotive single-bus communication circuit according to claim 1, characterized in that It includes a first pre-driver chip U2, a first MOS transistor Q1, and a fifth resistor R5. The input terminal of the first pre-driver chip U2 is connected to the output port of the MCU. The output terminal of the first pre-driver chip U2 is connected to the gate of the first MOS transistor Q1. The source of the first MOS transistor Q1 is connected to the input / output port and one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to the power supply V bat .

6. The automotive single-bus communication circuit according to claim 5, wherein The first MOS transistor Q1 is an NMOS transistor.

7. The automotive single-bus communication circuit according to claim 5, wherein The first pre-driver U2 is a MOSFET pre-driver chip.

8. The automotive single-bus communication circuit according to claim 5, wherein The power supply V bat is the power supply.