Novel vehicle-mounted LIN port anti-interference circuit

Abstract

The utility model relates to a novel vehicle-mounted LIN port anti-interference circuit, which comprises an LIN transceiver and an LIN connector, an LIN interface of the LIN transceiver is connected with one end of a BDL filter, and the other end of the BDL filter is connected with one end of an ESD device and the LIN connector; the other end of the ESD device is grounded; according to the design, the scheme that the ESD tube and the BDL are combined is adopted, the ESD tube inhibits transient high voltage of static electricity, interference energy is reduced, and chip protection is achieved; through the BDL filter, the effect of filtering high-frequency crosstalk noise of other wire harnesses is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to vehicle LIN port anti-interference technical field more specifically, relate to a novel vehicle LIN port anti-interference circuit. BACKGROUND

[0002] LIN is the communication protocol commonly used in automobile application, through LIN network, the information transmission between different control units on the vehicle can be realized.In practical application, the main control chip transmits information to LIN transceiver chip, and then conducts through connector, wire harness and other physical media.As the connector and wire harness are exposed, they are easily interfered by electrostatic discharge (ESD) and space radio frequency field.To solve this problem, a novel vehicle LIN port anti-interference circuit is needed. SUMMARY

[0003] The utility model solves the technical problem in the prior art, and provides a novel vehicle LIN port anti-interference circuit for solving the breakdown of LIN receiving chip and abnormal signal when LIN interface technology is applied and interfered by static electricity and high-frequency coupling crosstalk between wire harnesses.

[0004] The utility model adopts the technical scheme that:

[0005] A novel vehicle LIN port anti-interference circuit is constructed, which comprises a LIN transceiver and a LIN connector, wherein the LIN interface of the LIN transceiver is connected with one end of a BDL filter, the other end of the BDL filter is connected with one end of an ESD device and the LIN connector, and the other end of the ESD device is grounded.

[0006] The novel vehicle LIN port anti-interference circuit comprises a LIN transceiver and a LIN connector, wherein the power supply input pin of the LIN transceiver is connected with a diode and a resistor in sequence, the anode of the diode is connected with the power supply input pin, the cathode is connected with one end of the resistor, and the other end of the resistor is connected with the LIN interface of the LIN transceiver.

[0007] The novel vehicle LIN port anti-interference circuit comprises a LIN transceiver and a LIN connector, wherein the LIN interface of the LIN transceiver is connected with an inductor, and the other end of the inductor is connected with the other end of the resistor and one end of the BDL filter.

[0008] The utility model has the advantages that: the design adopts the scheme that ESD tube and BDL are combined, the ESD tube suppresses the transient high voltage of static electricity, reduces interference energy, and realizes the protection of the chip; through the BDL filter, the effect of filtering the high-frequency crosstalk noise of other wire harnesses is realized. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application or the prior art will be further described below in combination with the drawings and embodiments. The drawings in the following description are only partial embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the premise of not paying creative labor.

[0010] Figure 1 is a new vehicle LIN port anti-interference circuit diagram of the embodiment one of the present application;

[0011] Figure 2 is a new vehicle LIN port anti-interference circuit electrostatic discharge transient current curve diagram of the embodiment one of the present application;

[0012] Figure 3 is a new vehicle LIN port anti-interference circuit electrostatic suppression schematic diagram of the embodiment one of the present application;

[0013] Figure 4 is a new vehicle LIN port anti-interference circuit large current injection method test test level schematic diagram of the embodiment one of the present application;

[0014] Figure 5 is a new vehicle LIN port anti-interference circuit BDL filter working principle diagram of the embodiment one of the present application;

[0015] Figure 6 is a new vehicle LIN port anti-interference circuit BDL filter component schematic diagram of the embodiment one of the present application;

[0016] Figure 7 is a new vehicle LIN port anti-interference circuit diagram of the embodiment two of the present application;

[0017] Figure 8 is a new vehicle LIN port anti-interference circuit BDL filter component schematic diagram of the embodiment two of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application or the prior art will be further described below in combination with the drawings and embodiments. The drawings in the following description are only partial embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the premise of not paying creative labor.

[0019] Embodiment one

[0020] The new vehicle LIN port anti-interference circuit of the preferred embodiment of the present application, such as Figure 1As shown in the drawings, and with reference to Figures 2-6 , comprising a LIN transceiver and a LIN connector, the LIN interface of the LIN transceiver is connected with one end of a BDL filter, the other end of the BDL filter (identified as BDL in the figure) is connected with one end of an ESD device (identified as ESD in the figure) and the LIN connector; the other end of the ESD device is grounded; the power input pin of the LIN transceiver is connected with a diode and a resistor R in sequence; the anode of the diode is connected with the power input pin, the cathode is connected with one end of the resistor R, and the other end of the resistor R is connected with the LIN interface of the LIN transceiver;

[0021] The design adopts a combination scheme of an ESD tube and a BDL, the ESD tube suppresses the transient high voltage of static electricity and reduces interference energy, thereby realizing protection of the chip; through the BDL filter, the effect of filtering out high-frequency crosstalk noise of other wire harnesses is realized.

[0022] The circuit protection principle is explained as follows:

[0023] (1) Static protection process: static discharge will excite transient large current, high voltage and spatial electromagnetic field interference, and the transient current curve of static discharge is as shown in Figure 2 .

[0024] The transient static energy enters into the circuit through conduction or spatial electromagnetic field induction, which will cause damage to the chip on one hand and will cause the signal line to be interfered by the electromagnetic field generated during the transient discharge, and the induced voltage is superimposed on the signal, which will cause adverse effects on the signal quality.

[0025] The design suppresses the transient high voltage generated during the static discharge moment and the static transient interference induced by the wire harness through the ESD tube, and the static suppression process of the ESD is as follows: when a very strong static interference voltage is induced on the LIN signal line, generally in the range of hundreds of volts to thousands of volts, the static suppressor will act instantaneously, and the ESD changes from a high-impedance state to a low-impedance state instantaneously, the transient energy is discharged to the ground circuit through the ESD, thereby only leaving the clamping voltage after the action of the ESD, the energy is greatly reduced, and the damage to the chip on the link is greatly reduced, as shown in Figure 3 .

[0026] In the anti-interference test of vehicle-mounted products, the large current injection method (BCI) test of parts is generally used to simulate the radio frequency coupling interference between wire harnesses, and the test level is as shown in Figure 4As shown in the BCI test, the test frequency range is from 100KHz to 400MHz, the maximum injection current is 200mA, and for such a wide frequency range and large interference energy, a general filter device cannot achieve complete interference suppression. Here we select the filter device BDL with a larger filter bandwidth and higher insertion loss for protection. Since the BDL filter is connected in parallel to the circuit, it provides a low impedance path for noise. In an ideal case, without considering the distributed inductance of the wire harness, the BDL filter can achieve filtering effect on the entire signal path. At this time, regardless of the position of the voltage induction at the signal sending end, the receiving end or the cable, the BDL can provide a low impedance path to achieve noise filtering. The working process of BDL is as shown in Figure 4 ;

[0027] Example Two

[0028] Another preferred embodiment of the novel vehicle-mounted LIN port anti-interference circuit of the application is shown in Figure 7 , and reference is made to Figure 8 . This embodiment is basically the same as example one, and the same parts will not be described again. The difference is that the LIN interface of the LIN transceiver is connected with an inductor L, and the other end of the inductor L is connected with the other end of the resistor R and one end of the BDL filter.

[0029] This design uses an ESD tube as an electrostatic protection, and a combination of BDL and inductor L. The ESD tube suppresses the transient high voltage of static electricity and reduces the interference energy to protect the chip. Through the BDL filter and the inductor L, the high-frequency crosstalk noise of other wire harnesses is filtered out.

[0030] The principle is explained as follows:

[0031] As shown in Figure 8 , a two-stage filter circuit is formed by the filter device BDL and the inductor L for protection. Since the BDL filter is connected in parallel to the circuit, it provides a low impedance path for noise. In an ideal case, without considering the distributed inductance of the wire harness, the BDL filter can achieve filtering effect on the entire signal path. At this time, regardless of the position of the voltage induction at the signal sending end, the receiving end or the cable, the BDL can provide a low impedance path to achieve noise filtering. The inductor L at the back end of the BDL can achieve secondary suppression of the residual interference noise after BDL filtering, ensure that the signal level is more stable and clean, and improve the reliability of signal communication.

[0032] It should be understood that those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the utility model.

Claims

1. A new type of anti-interference circuit for a LIN port in a vehicle, comprising a LIN transceiver and a LIN connector, characterized in that, The LIN interface of the LIN transceiver is connected with one end of a BDL filter, the other end of the BDL filter is connected with one end of an ESD device and the LIN connector; the other end of the ESD device is grounded.

2. The new tamper-resistant circuit for a LIN port on board a vehicle according to claim 1, characterized in that, The power supply input pin of the LIN transceiver is connected with a diode and a resistor in sequence; the anode of the diode is connected with the power supply input pin, the cathode is connected with one end of the resistor, and the other end of the resistor is connected with the LIN interface of the LIN transceiver.

3. The new tamper-resistant circuit for a LIN port on board a vehicle according to claim 2, characterized in that, The LIN interface of the LIN transceiver is connected with an inductor, and the other end of the inductor is connected with the other end of the resistor and one end of the BDL filter. The LIN interface of the LIN transceiver is connected with an inductor, and the other end of the inductor is connected with the other end of the resistor and one end of the BDL filter.

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