Interface circuit and device of vehicle-mounted Ethernet

Abstract

The invention discloses a vehicle-mounted Ethernet interface circuit and device. The vehicle-mounted Ethernet interface circuit comprises an interface connector, an electromagnetic protection module and a physical layer chip, wherein the electromagnetic protection module comprises a signal protection unit and a signal optimization unit, the electromagnetic protection module is connected with the interface connector through the signal protection unit, and the electromagnetic protection module is connected with the physical layer chip through the signal optimization unit; the interface connector provides a connecting interface and is used for receiving a first electric signal of an external module; the signal protection unit is used for performing electrostatic discharge protection on the first electric signal and outputting a second electric signal; the signal optimization unit is used for carrying out common-mode rejection and signal edge slow release on the second electric signal and outputting a third electric signal; and the physical layer chip is used for receiving the third electric signal. According to the technical scheme, the EMC performance of the domain controller is improved, the electromagnetic radiation and conducted interference of the domain controller are reduced, the safety of devices is protected, the failure rate of the domain controller is reduced, the test rectification time of the domain controller is shortened, and the after-sales maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to an interface circuit and device for vehicle-mounted Ethernet. Background Art

[0002] As automotive electronic architecture develops from distributed to centralized, automotive electronic communication architecture is also developing from low-speed communication bus to Ethernet high-speed communication, and large-bandwidth communication architecture is adapted to the increasing data volume and low latency requirements of vehicles.

[0003] Under the new architecture, the demand for in-vehicle Ethernet is increasing. Intelligent driving domain controllers, intelligent cockpit domain controllers, and intelligent vehicle control domain controllers all rely on a large amount of in-vehicle Ethernet. All automotive components must undergo electromagnetic compatibility (EMC) testing and verification to ensure application quality. Domain controllers that carry a large number of high-speed signals, such as Ethernet, create a complex electromagnetic environment. Therefore, an in-vehicle Ethernet interface that can reduce electromagnetic radiation is urgently needed. Summary of the Invention

[0004] The present invention provides an interface circuit and device for vehicle-mounted Ethernet, which suppress electromagnetic radiation interference and conducted interference of a domain controller and protect device safety.

[0005] In a first aspect, embodiments of the present disclosure provide an in-vehicle Ethernet interface circuit, comprising: an interface connector, an electromagnetic protection module, and a physical layer chip; wherein the electromagnetic protection module includes a signal protection unit and a signal optimization unit, the electromagnetic protection module being connected to the interface connector via the signal protection unit and to the physical layer chip via the signal optimization unit;

[0006] The interface connector provides a connection interface for receiving a first electrical signal from an external module;

[0007] The signal protection unit is configured to obtain the first electrical signal, perform electrostatic discharge protection on the first electrical signal, and output a second electrical signal;

[0008] The signal optimization unit is configured to obtain the second electrical signal, perform common-mode suppression and signal edge slowing on the second electrical signal, and output a third electrical signal;

[0009] The physical layer chip is used to receive the third electrical signal.

[0010] In a second aspect, an embodiment of the present disclosure provides an interface device for in-vehicle Ethernet, comprising: an interface circuit board and a metal shell covering the interface circuit board, wherein the interface circuit board integrates the interface circuit as described in the first aspect; the interface circuit board is connected to the metal shell by a pressing process.

[0011] An embodiment of the present invention provides an in-vehicle Ethernet interface circuit and device, comprising: an interface connector, an electromagnetic protection module, and a physical layer chip; wherein the electromagnetic protection module includes a signal protection unit and a signal optimization unit, the electromagnetic protection module being connected to the interface connector via the signal protection unit and to the physical layer chip via the signal optimization unit; the interface connector providing a connection interface for receiving a first electrical signal from an external module; the signal protection unit being configured to acquire the first electrical signal, perform electrostatic discharge protection on the first electrical signal, and output a second electrical signal; the signal optimization unit being configured to acquire the second electrical signal, perform common-mode suppression and signal edge mitigation on the second electrical signal, and output a third electrical signal; and the physical layer chip being configured to receive the third electrical signal. The interface circuit can enable the radiation emission test of a domain controller to meet the Class 5 level of the national standard GB / T18655, thereby improving the EMC performance of the domain controller, reducing its electromagnetic radiation, and reducing its failure rate, thereby reducing the time required for domain controller testing and rectification, and lowering after-sales repair costs.

[0012] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 This is a structural diagram of an in-vehicle Ethernet interface circuit provided by the first embodiment of the present invention;

[0015] Figure 2 This is a schematic structural diagram of another in-vehicle Ethernet interface circuit provided by the first embodiment of the present invention;

[0016] Figure 3 This is a structural diagram of an in-vehicle Ethernet interface device provided in a second embodiment of the present invention.

[0017] Figure 4 This is a structural diagram of an interface circuit board in an in-vehicle Ethernet interface device provided by Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solutions 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. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0019] It should be noted that the terms "first," "second," and "target" and the like in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this way are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatus.

[0020] With the development of automotive domain controllers, the electromagnetic environment in vehicles is becoming increasingly complex, and electromagnetically-induced failures are increasing. For domain controllers that handle a large number of high-speed signals, such as Ethernet, the electromagnetic environment is complex. Industry-standard EMC testing for radiated emissions typically only meets the national standard GB18655-class 3, rarely reaching the national standard GB18655-class 5. Therefore, this invention proposes an EMC design solution for in-vehicle Ethernet, including an interface circuit and device for in-vehicle Ethernet, to improve the EMC performance of domain controllers and reduce their electromagnetic radiation.

[0021] Example 1

[0022] Figure 1 This is a schematic diagram of the structure of an in-vehicle Ethernet interface circuit provided by the first embodiment of the present invention. Figure 1 As shown, the interface circuit 1 includes: an interface connector 11, an electromagnetic protection module 12 and a physical layer chip 13; wherein the electromagnetic protection module 12 includes a signal protection unit 121 and a signal optimization unit 122, and the electromagnetic protection module 12 is connected to the interface connector 11 through the signal protection unit 121, and is connected to the physical layer chip 13 through the signal optimization unit 122;

[0023] The interface connector 11 provides a connection interface for receiving a first electrical signal from an external module;

[0024] a signal protection unit 121, configured to obtain a first electrical signal, perform electrostatic discharge protection on the first electrical signal, and output a second electrical signal;

[0025] a signal optimization unit 122 configured to acquire the second electrical signal, perform common-mode suppression and signal edge mitigation on the second electrical signal, and output a third electrical signal;

[0026] The physical layer chip 13 is configured to receive a third electrical signal.

[0027] In this embodiment, the interface connector 11 is the Ethernet external connector of the domain controller. The external module can be understood as other devices electrically connected to the interface connector 11, for example, other interface connectors, other chips, etc. The first electrical signal can be understood as the electrical signal directly obtained by the interface connector 11. The second electrical signal can be understood as the first electrical signal after electrostatic discharge (ESD) protection processing. The third electrical signal can be understood as the second electrical signal after common mode suppression and signal edge release processing. The physical layer chip is an Ethernet physical layer chip, such as a Switch or PHY chip.

[0028] Specifically, in this embodiment, the interface connector 11 is a shielded connector specifically designed for in-vehicle Ethernet. The interface connector 11 provides a connection interface, receives a first electrical signal transmitted from an external module, and transmits the first electrical signal to the signal protection unit 121. After receiving the first electrical signal, the signal protection unit 121 performs electrostatic discharge protection on the first electrical signal using a transient voltage suppressor (TVS) diode, and outputs a second electrical signal to the signal optimization unit 122. After receiving the second electrical signal, the signal optimization unit 122 performs common-mode suppression on the second electrical signal, performs signal edge release protection on the second electrical signal after common-mode suppression, and outputs a third electrical signal to the physical layer PHY chip. The physical layer chip 13 receives the third electrical signal transmitted by the signal optimization unit 122.

[0029] The interface connector 11 , the electromagnetic protection module 12 and the physical layer chip 13 are electrically connected via signal lines, and the components in the electromagnetic protection module 12 are also connected via signal lines.

[0030] An embodiment of the present invention provides an in-vehicle Ethernet interface circuit, comprising: an interface connector, an electromagnetic protection module, and a physical layer chip; wherein the electromagnetic protection module includes a signal protection unit and a signal optimization unit, the electromagnetic protection module being connected to the interface connector via the signal protection unit and to the physical layer chip via the signal optimization unit; the interface connector providing a connection interface for receiving a first electrical signal from an external module; the signal protection unit being configured to acquire the first electrical signal, perform electrostatic discharge protection on the first electrical signal, and output a second electrical signal; the signal optimization unit being configured to acquire the second electrical signal, perform common-mode suppression and signal edge slowing on the second electrical signal, and output a third electrical signal; and the physical layer chip being configured to receive the third electrical signal. The interface circuit can enable the radiation emission test of a domain controller to meet the Class 5 level of the national standard GB / T 18655, thereby improving the EMC performance of the domain controller, reducing the electromagnetic radiation and conducted interference of the domain controller, protecting the device safety, and reducing the failure rate of the domain controller, thereby reducing the test rectification time of the domain controller and reducing after-sales maintenance costs.

[0031] Figure 2 1 is a schematic diagram of the structure of another vehicle Ethernet interface circuit provided by the first embodiment of the present invention. As a first optional embodiment of this embodiment, Figure 2 As shown, the signal protection unit includes a first diode TVS1 and a second diode TVS2, the first end of the first diode TVS1 is connected to the anode of the interface connector, the second end of the first diode TVS1 is connected to the first end of the second diode TVS2, the second end of the second diode TVS2 is connected to the cathode of the interface connector, and the second end of the first diode TVS1 and the first end of the second diode TVS2 are grounded through a common node.

[0032] In this embodiment, the first diode can be understood as a TVS diode for performing preliminary ESD protection and suppressing electrostatic discharge interference. The second diode can be understood as another TVS diode for performing further ESD protection, that is, further suppressing residual electrostatic interference. The first diode and the second diode are connected in series. The first end can be understood as one end of the diode, and the second end can be understood as the other end of the diode. The common node can be understood as the node where the first diode and the second diode are connected in series.

[0033] Specifically, the signal protection unit consists of two TVS diodes, one end of TVS1 is connected to the positive pole TRDP of the interface connector, the other end of TVS1 is connected to one end of TVS2, the other end of TVS2 is connected to the negative pole TRDN of the interface connector, and TVS1 and TVS2 are grounded through a common node.

[0034] As a second optional embodiment of this embodiment, Figure 2As shown, the signal optimization unit includes a common-mode termination subunit, a direct isolation subunit, a common-mode inductor, and a signal edge-release subunit; the common-mode termination subunit is connected to the direct isolation subunit, the direct isolation subunit is connected to the common-mode inductor, the common-mode inductor is connected to the signal edge-release subunit, the signal optimization unit is connected to the signal protection unit through the common-mode termination subunit, and is connected to the interface connector through the signal edge-release subunit;

[0035] Common-mode termination subunit, used to form a common-mode termination network for in-vehicle Ethernet;

[0036] DC isolation subunit, used to block the DC path and retain the AC signal;

[0037] Common-mode inductor, used to suppress common-mode interference on signal lines;

[0038] The signal edge slowing subunit is used to reduce electromagnetic radiation by slowing down the signal edge.

[0039] In this embodiment, the common-mode termination subunit is composed of three resistors and one capacitor, which are used to form the common-mode termination network of the in-vehicle Ethernet. The common-mode termination subunit is connected to the signal protection unit, and is respectively connected to the first end of the first diode and the second end of the second diode in the signal protection unit. The direct isolation subunit is composed of two direct isolation capacitors, which are used to block the DC path and retain the AC signal. The direct isolation subunit is connected to the common-mode termination subunit. The common-mode inductor (CMC) is used to suppress common-mode interference on the differential data line. The common-mode inductor is connected to the direct isolation subunit. The signal edge release subunit is composed of two capacitors to ground. The signal edge release subcircuit is connected to the common-mode inductor and is also connected to the physical layer chip.

[0040] Specifically, after the common-mode termination sub-unit receives the second electrical signal transmitted by the signal protection unit, it filters out high-frequency common-mode noise and outputs the processed second electrical signal to the direct-isolation sub-unit. The direct-isolation sub-unit performs DC blocking processing on the signal and transmits the second electrical signal after DC blocking processing to the common-mode inductor. The common-mode inductor suppresses common-mode interference on the signal and transmits the second electrical signal after common-mode interference suppression to the signal edge release sub-unit. The signal edge release sub-unit performs signal edge slowing processing on the signal and transmits the processed third electrical signal to the physical layer chip.

[0041] Furthermore, the common-mode termination subunit includes a first resistor R1, a second resistor R2, a third resistor R3 and a first capacitor C1, the first end of the first resistor R1 is respectively connected to the signal protection unit and the direct isolation subunit, the second end of the first resistor R1 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is respectively connected to the signal protection unit and the direct isolation subunit, the first end of the third resistor R3 is connected to a common node between the second end of the first resistor R1 and the first end of the second resistor R2, the second end of the third resistor R3 is grounded, and the first capacitor C1 is connected in parallel to both ends of the third resistor R3.

[0042] In this embodiment, the first end can be understood as one end of a resistor or capacitor, and the second end can be understood as the other end of a resistor or capacitor. The first resistor R1, the second resistor R2, and the third resistor R3 are all resistors in the common-mode termination subunit. The first capacitor C1 can be understood as a capacitor in the common-mode termination subunit.

[0043] Specifically, the common-mode short-circuit network formed by the common-mode termination subunit suppresses common-mode signals and stabilizes differential signal transmission through impedance matching. The first resistor R1 and the second resistor R2 are connected in series between the positive and negative ends of the differential signal line (differential data line), the first end of the first resistor R1 is respectively connected to the first end of the first diode TVS1 in the signal protection unit and the first end of the second capacitor C1 in the direct isolation subunit, the second end of the second resistor R2 is respectively connected to the second end of the second diode TVS2 in the signal protection unit and the first end of the second capacitor C2 in the direct isolation subunit, the second end of the first resistor R1 and the first end of the second resistor R2 are connected to the first end of the third resistor R3 through a common node, and the second end of the third resistor R3 is grounded. The first capacitor C1 is connected in parallel to both ends of the third resistor R3, or the first end of the first capacitor C1 is connected to the common node between the second end of the first resistor R1 and the first end of the second resistor R2, and the second end of the first capacitor C1 is grounded.

[0044] Furthermore, the direct-isolation subunit includes a second capacitor C2 and a third capacitor C3. The second capacitor C2 and the third capacitor C3 are connected in parallel and are both connected between the common-mode termination subunit and the common-mode inductor.

[0045] In this embodiment, the second capacitor C2 and the third capacitor C3 are DC isolation capacitors in the DC isolation sub-unit.

[0046] Specifically, the second capacitor C2 is connected to the first end of the first resistor R1 in the common-mode termination subunit via a first end, and the second capacitor C2 is connected to the first end of the common-mode inductor CMC via a second end. The third capacitor C3 is connected to the second end of the second resistor R2 in the common-mode termination subunit via a first end, and the third capacitor C3 is connected to the second end of the common-mode inductor CMC via a second end.

[0047] Furthermore, the signal edge release sub-unit includes a fourth capacitor Cemi1 and a fifth capacitor Cemi2, the first end of the fourth capacitor Cemi1 is connected to the positive pole of the common-mode inductor CMC and the physical layer chip respectively, the second end of the fourth capacitor Cemi1 is connected to the first end of the fifth capacitor Cemi2, the second end of the fifth capacitor Cemi2 is connected to the negative pole of the common-mode inductor CMC and the physical layer chip respectively, and the second end of the fourth capacitor Cemi1 and the first end of the fifth capacitor Cemi2 are grounded through a common node.

[0048] In this embodiment, the fourth capacitor Cemi1 and the fifth capacitor Cemi2 are ground capacitors in the signal edge slowing subunit, both of which are 100Base-T1 ground capacitors used to slow down signal edges and reduce electromagnetic interference (EMI) radiation. The first end can be understood as one end of the capacitor, and the second end can be understood as the other end of the capacitor.

[0049] Specifically, the first end of the fourth capacitor Cemi1 is connected to the third end of the common-mode inductor CMC, and is also connected to the positive electrode TRDP of the physical layer chip. The second end of the fourth capacitor Cemi1 is connected to the first end of the fifth capacitor Cemi2. The second end of the fifth capacitor Cemi2 is connected to the fourth end of the common-mode inductor CMC, and is also connected to the negative electrode TRDN of the physical layer chip. The second end of the fourth capacitor Cemi1 and the first end of the fifth capacitor Cemi2 are grounded through a common node.

[0050] It is understandable that in-vehicle Ethernet includes 100base-T1 interfaces and 1000base-T1 interfaces. However, at a rate of 1000Mbps, the ground capacitance Cemi will cause signal distortion and is not suitable for 1000Base-T1.

[0051] Example 2

[0052] Figure 3 This is a structural diagram of an in-vehicle Ethernet interface device provided in a second embodiment of the present invention.

[0053] like Figure 3 As shown, the interface device 2 includes: an interface circuit board 21 and a metal shell 22 covering the interface circuit board 21, wherein the interface circuit board 21 integrates the interface circuit 1; the interface circuit board 21 is connected to the metal shell 22 by a pressing process.

[0054] In this embodiment, the interface circuit board 21 can be understood as an integrated circuit. Figure 2 The metal housing 22 can be understood as the outer shell of the interface circuit board 21 .

[0055] Specifically, the interface device 2 is composed of an interface circuit board 21 and a metal shell 22 covering the interface circuit board 21, and the interface circuit board 21 and the metal shell 22 are tightly connected by a press edge process. The interface device 2 can be connected to other interface devices or chips.

[0056] Figure 4 is a structural schematic diagram of an interface circuit board in an interface device of a vehicle-mounted Ethernet provided by the second embodiment of the present application. As shown in Figure 4 , the PCB is provided with an interface connector, a TVS diode, resistors R1, R2 and R3, capacitors C1, C2 and C3, a common mode inductor CMC, ground capacitors Cemi1 and Cemi2, and a physical layer chip. The interface connector and the physical layer chip each include a positive electrode T1P and a negative electrode T2P.

[0057] As a first alternative embodiment of the present embodiment, the interface circuit board is connected to the shielding layer of the interface connector in the interface circuit through a ground layer of the circuit board; and the spacing between the common mode inductor in the interface circuit and the interface connector on the interface circuit board is less than a set distance threshold.

[0058] In the present embodiment, the set distance threshold is a maximum distance value between the common mode inductor and the interface connector that is set in advance.

[0059] Specifically, when the interface circuit board is wired, the shielding layer of the interface connector in the interface circuit is connected to the ground layer of the printed circuit board of the interface circuit board itself. The spacing between the common mode inductor in the interface circuit and the interface connector on the interface circuit board is less than a set distance threshold, so that the common mode inductor is as close to the interface connector as possible.

[0060] As a second alternative embodiment of the present embodiment, the interface circuit integrated in the interface circuit board uses a differential data line as a signal line, and the differential data line satisfies a set wiring condition.

[0061] In the present embodiment, the set wiring condition can be understood as a condition that needs to be satisfied based on the wiring of the interface circuit on the printed circuit board that is set in advance.

[0062] Specifically, the interface circuit integrated in the interface circuit board uses a differential data line as a signal line, and the signal line must have a complete ground plane as a reference ground; the signal line is differentially routed and equal in length, and the length error between differential pairs is within 5 mil; the signal line is prohibited from crossing the partition; and the signal line is ground wrapped. If ground wrapping is not possible, it is ensured that the spacing between each group of differential data lines and other signal lines and power lines is greater than 30 mil.

[0063] It is understood that the interface circuit has impedance matching characteristics, and the impedance is preferably 100Ω±10%. In addition, a maximum of two vias are allowed when changing layers on a 100Base-T1 signal line, and accompanying ground vias must be drilled next to the layer change vias; no vias are allowed on a 1000Base-T1 signal line.

[0064] As a third optional embodiment of this embodiment, the metal shell includes an upper shell and a lower shell, the interface circuit board is connected to the upper shell and the lower shell respectively, and the upper shell and the lower shell have groove frills.

[0065] In this embodiment, both the upper and lower housings are metal components, each with grooved hems. These hems are embedded to achieve a press-fit process between the upper and lower housings and the interface circuit board. The press-fit process also includes injecting conductive adhesive to reduce gaps between the three components and enhance shielding. Furthermore, the interface connector on the interface circuit board is a shielded connector specifically designed for automotive Ethernet.

[0066] An embodiment of the present invention provides an in-vehicle Ethernet interface device, comprising: an interface circuit board and a metal housing covering the interface circuit board, the interface circuit board integrating the interface circuit; the interface circuit board is connected to the metal housing via a crimping process. This patent proposes an EMC design scheme for in-vehicle Ethernet, primarily through forward design from three aspects: domain controller schematic design, PCB design, and structural design. This allows automotive components incorporating in-vehicle Ethernet to pass tests in accordance with both IEC-CISPR25 and GB / T 18655 - Radio disturbance characteristics of vehicles, ships, and internal combustion engines - Limits and measurement methods for protecting on-board receivers. This ensures the stable operation of the vehicle's electrical system and prevents electromagnetic interference from affecting other vehicles or equipment.

[0067] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0068] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. An interface circuit for vehicle-mounted Ethernet, characterized in that: include: An interface connector, an electromagnetic protection module, and a physical layer chip; wherein the electromagnetic protection module includes a signal protection unit and a signal optimization unit, the electromagnetic protection module is connected to the interface connector via the signal protection unit, and is connected to the physical layer chip via the signal optimization unit; The interface connector provides a connection interface for receiving a first electrical signal from an external module; The signal protection unit is configured to obtain the first electrical signal, perform electrostatic discharge protection on the first electrical signal, and output a second electrical signal; The signal optimization unit is configured to obtain the second electrical signal, perform common-mode suppression and signal edge slowing on the second electrical signal, and output a third electrical signal; The physical layer chip is used to receive the third electrical signal.

2. The interface circuit according to claim 1, wherein: The signal protection unit includes a first diode and a second diode, the first end of the first diode is connected to the positive electrode of the interface connector, the second end of the first diode is connected to the first end of the second diode, the second end of the second diode is connected to the negative electrode of the interface connector, and the second end of the first diode and the first end of the second diode are grounded through a common node.

3. The interface circuit according to claim 1, wherein: The signal optimization unit includes a common-mode termination subunit, a direct isolation subunit, a common-mode inductor, and a signal edge-release subunit; the common-mode termination subunit is connected to the direct isolation subunit, the direct isolation subunit is connected to the common-mode inductor, the common-mode inductor is connected to the signal edge-release subunit, the signal optimization unit is connected to the signal protection unit through the common-mode termination subunit, and is connected to the interface connector through the signal edge-release subunit; The common-mode termination subunit is used to form a common-mode termination network of the in-vehicle Ethernet; The DC isolation subunit is used to block the DC path and retain the AC signal; The common-mode inductor is used to suppress common-mode interference on the signal line; The signal edge slowing subunit is used to reduce electromagnetic radiation by slowing down the signal edge.

4. The interface circuit according to claim 3, wherein: The common-mode termination subunit includes a first resistor, a second resistor, a third resistor and a first capacitor, the first end of the first resistor is respectively connected to the signal protection unit and the direct isolation subunit, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is respectively connected to the signal protection unit and the direct isolation subunit, the first end of the third resistor is connected to a common node between the second end of the first resistor and the first end of the second resistor, and the second end is grounded, and the first capacitor is connected in parallel to both ends of the third resistor.

5. The interface circuit according to claim 3, wherein: The direct current isolation subunit includes a second capacitor and a third capacitor. The second capacitor and the third capacitor are connected in parallel and are both connected between the common mode termination subunit and the common mode inductor.

6. The interface circuit according to claim 3, characterized in that: The signal edge release subunit includes a fourth capacitor and a fifth capacitor, the first end of the fourth capacitor is respectively connected to the common-mode inductor and the positive electrode of the physical layer chip, the second end of the fourth capacitor is connected to the first end of the fifth capacitor, the second end of the fifth capacitor is respectively connected to the common-mode inductor and the negative electrode of the physical layer chip, and the second end of the fourth capacitor and the first end of the fifth capacitor are grounded through a common node.

7. An interface device for vehicle-mounted Ethernet, characterized in that: include: An interface circuit board and a metal housing covering the interface circuit board, wherein the interface circuit board is integrated with the interface circuit according to any one of claims 1 to 6; The interface circuit board is connected to the metal shell through a crimping process.

8. The interface device according to claim 7, characterized in that: The interface circuit board is connected to the shielding layer of the interface connector in the interface circuit through a circuit board ground layer; the distance between the common mode inductor in the interface circuit and the interface connector on the interface circuit board is less than a set distance threshold.

9. The interface device according to claim 7, characterized in that: The interface circuit integrated in the interface circuit board uses differential data lines as signal lines, and the differential data lines meet set wiring conditions.

10. The interface device according to claim 7, characterized in that: The metal shell includes an upper shell and a lower shell, the interface circuit board is connected to the upper shell and the lower shell respectively, and the upper shell and the lower shell have groove hems.

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