CN114258257A

CN114258257A - Electronic control unit and method for improving electromagnetic compatibility by using same

Info

Publication number: CN114258257A
Application number: CN202111546570.7A
Authority: CN
Inventors: 李军; 龚璐; 张风; 关岩; 刘利峰; 刘佳月
Original assignee: Zongmu Technology Shanghai Co Ltd
Current assignee: Zongmu Technology Shanghai Co Ltd
Priority date: 2021-12-16
Filing date: 2021-12-16
Publication date: 2022-03-29

Abstract

The invention provides an electronic control unit and a method for improving electromagnetic compatibility by using the same. The ground of the circuit board of the electronic control unit is divided into an interface ground and a logic ground; the ground of the input/output interface connector of the electronic control unit is used as an interface ground, the ground is used as a part of a shell ground and is connected with the metal shell of the electronic control unit, and a shielding mechanism is arranged on one side of the interface ground and the logic ground at the division position close to the interface ground, so that the electromagnetic compatibility of the electronic control unit can be effectively improved.

Description

Electronic control unit and method for improving electromagnetic compatibility by using same

Technical Field

The invention relates to the technical field of electronic control units, in particular to an electronic control unit and a method for improving electromagnetic compatibility by using the same.

Background

The Electronic Control Unit (ECU) is the core component of automobile electronics and consists of a microprocessor, a memory, an input/output interface, an analog-to-digital conversion and other integrated circuits. The electronic control unit receives and processes the signals from the sensors, calculates the control signals transmitted to the controller, is the brain of the automobile and has strict electromagnetic compatibility requirements. Electronic control units with higher power typically use a metal housing to facilitate heat dissipation while enhancing electromagnetic compatibility.

At present, the electromagnetic compatibility design method of the electronic control unit using the metal shell includes filtering, frequency spreading, controlling loop area, shell shielding, 360 ° lap joint of an input/output interface connector, using a shielding cover for internal high-frequency components, using a shielding wire harness, and the like. Electronic control units using these techniques can solve most but not all of the electromagnetic compatibility problems well because designers often mix input-output interface processing with the logic inside the circuit, ignoring them. The ground inside the existing circuit board is not divided, the ground of the input/output interface and the ground of the internal circuit are the same ground and are uniformly connected to the metal shell, shielding treatment is not carried out inside the circuit board or only a shielding cover is used for a high-frequency component, radiation exceeding is easily caused by internal noise, and meanwhile external interference can be directly coupled to the logic ground of the internal circuit through the ground of the input/output interface, so that the radiation anti-interference performance of the electronic control unit is reduced.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to provide an electronic control unit and a method for improving electromagnetic compatibility applied thereto, which solve the above deficiencies in the prior art.

To achieve the above and other related objects, the present invention provides an electronic control unit whose circuit board ground is divided into an interface ground and a logic ground; the ground of the input/output interface connector of the electronic control unit is used as an interface ground, and the ground is used as a part of the shell ground and is connected with the metal shell of the electronic control unit.

To achieve the above and other related objects, the present invention provides a method for improving electromagnetic compatibility of an electronic control unit, comprising: dividing a ground of a circuit board of the electronic control unit into an interface ground and a logic ground; the ground of the input/output interface connector of the electronic control unit is used as an interface ground, and the interface ground is used as a part of the shell ground and is connected with the metal shell of the electronic control unit.

To achieve the above and other related objects, the present invention provides a domain controller whose circuit board ground is divided into an interface ground and a logic ground; the ground of the input/output interface connector of the domain controller is used as an interface ground, and the ground is used as a part of the shell ground and is connected with the metal shell of the domain controller.

To achieve the above and other related objects, the present invention provides an electronic device including the electronic control unit, or the domain controller.

As described above, according to the electronic control unit and the method for improving electromagnetic compatibility applied thereto of the present invention, a circuit ground division and shielding scheme for the input/output interface is proposed, by dividing the ground of the circuit board of the electronic control unit into the interface ground and the logic ground, taking the ground of the input/output interface connector of the electronic control unit as the interface ground, which is connected to the metal casing of the electronic control unit as a part of the casing ground, the external interference signal and the internal radiation signal can be quickly discharged to the ground through the casing, thereby improving the electromagnetic compatibility of the electronic control unit.

Drawings

Fig. 1 is a schematic diagram of an electronic control unit in the prior art.

Fig. 2 is a schematic structural diagram of an electronic control unit according to an embodiment of the invention.

Fig. 3 is a schematic structural diagram of an upper cover of an electronic control unit according to an embodiment of the invention.

Fig. 4 is a schematic side perspective view of an electronic control unit according to an embodiment of the invention.

FIG. 5 is a flowchart illustrating a method for improving electromagnetic compatibility of an electronic control unit according to an embodiment of the present invention.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

Fig. 1 shows a schematic structural diagram of a conventional electronic control unit, in which an upper cover 1 and a lower cover 3 form a housing, a circuit board 2 is disposed inside the housing, and an input/output interface connector 4 is disposed on the circuit board 2. Because the ground in the existing circuit board is not divided, the ground of the input/output interface and the ground of the internal circuit are the same ground and are uniformly connected to the metal shell, the radiation anti-interference performance of the electronic control unit is poor. As an important part of an automobile, the improvement of performance of an electronic control unit has been one of the important issues in the industry.

With the development of intellectualization, networking and electromotion of the whole automobile industry, the attributes of vehicles gradually evolve from single individuals to nodes on a huge intelligent traffic network. The "tri-generation" brings the greatest change to the vehicle, which is to make the vehicle merge more and more closely with its surroundings, including road traffic facilities, other vehicles, various other nodes contained in the environment. Various functions added to the vehicle emphasize interaction with the environment, which brings new challenges to the verification of the electromagnetic compatibility test of the vehicle. Based on this, the present invention proposes a partitioning and shielding scheme for the input/output interface circuit to improve the electromagnetic compatibility of the electronic control unit, which is suitable for the conventional Electronic Control Unit (ECU) and also for the Domain Controller (DCU) and the central computer (Centralized Vehicle computer).

The solution of the invention will be described in detail below, taking an electronic control unit as an example. The domain controller is implemented in the same manner as the electronic control unit, and thus is not repeatedly developed.

Referring to fig. 2, the present embodiment provides an electronic control unit, wherein the ground of the circuit board 7 is divided into a "clean" interface ground 12 and a "dirty" logic ground 11. The split interface ground 12 and the logical ground 11 have a slot 8 between them, i.e. the interface ground 12 and the logical ground 11 are split into two parts by the slot 8.

All input-output interface connectors 4 of the electronic control unit are in the area of an interface ground 12, which has multiple low impedance connections to the housing to minimize inductance, which is partly considered as an extension of the housing, which is part of the housing ground. While logical ground 11 is a "dirty" digital logic ground plane, which is still a complete plane.

In one embodiment, the interface ground 12 and the logic ground 11 are connected by a bridge at one or a few points. Specifically, the low frequency input-output line crossing the slot 8 between the interface ground 12 and the logic ground 11 is connected to the input-output interface connector 4 through a signal line and a return path (ground line) 10; a bridge 13 is arranged across the high frequency input-output lines of the slot 8 between the interface ground 12 and the logic ground 11 to provide a continuous path for the return current for the signal lines. Note that the bridge 13 is provided in the ground layer, and the signal line is provided in the signal layer. Therefore, when the electronic control unit is interfered by the outside, the interference current can be quickly injected into the automobile body from the shell, and the interference of an internal logic circuit is avoided. Noise inside the electronic control unit can be quickly injected into the vehicle body from the shell, and radiation interference with other vehicle-mounted equipment is avoided.

In one embodiment, a plurality of shielding mechanisms 9 are disposed at a side of the interface ground 12 and the logic ground 11, which is divided and close to the interface ground 12. The shielding mechanism 9 may be made of a shielding material such as conductive foam. The shielding mechanism 9 is electrically connected with the interface ground 12 in a low impedance manner and is uniformly distributed in a straight line. Referring to fig. 3, a protrusion 5 is provided in an upper cover 6 of the metal case of the electronic control unit. The projections 5 are also arranged in a straight line and are matched with the positions of a plurality of shielding mechanisms 9 which are uniformly distributed in a straight line. After the upper cover 6 and the lower cover 3 of the metal housing are connected, the convex portions 5 are in close contact with the shielding mechanisms 9. By such arrangement, the circuit of the interface ground 12 and the circuit of the logic ground 11 can be shielded and isolated, and electromagnetic leakage of the internal circuit to the outside can be reduced.

In addition, referring to fig. 4, a gap 14 is formed between the position of the circuit board 7 (including the interface ground 12 and the logic ground 11 connected by the bridge) without the shielding mechanism 9 and the upper cover 6, and the shielding effectiveness of the uniformly distributed gap can be given by the following formula:

wherein f is the frequency, l is the length of the slot, and n is the number of slots. Suppose that: f is 1GHz, l is 1cm, n is 11, and S is 14dB, which means that the shielding effectiveness of the gaps formed between the uniformly distributed 10 shielding mechanisms and the upper cover at the frequency of 1GHz is 14 dB.

In summary, the ground of the electronic control unit circuit board of the present embodiment is divided into a "clean" interface ground and a "dirty" logic ground, and the ground of the input/output interface connector is used as the interface ground, which is directly connected to the metal housing as a part of the housing ground, so that the external interference signal and the internal radiation signal can be quickly discharged to the ground through the housing. Meanwhile, a shielding mechanism is mounted on one side of the partition close to the input/output interface and is used for contacting with the upper cover of the metal shell, so that the input/output interface connector circuit and the internal logic circuit are shielded and isolated. Therefore, the electromagnetic radiation emission of the electronic control unit is reduced, the anti-interference capability is improved, and the cost is not increased by the newly added shielding mechanism.

It should be noted that, in the existing scheme, a large number of common mode filters are used in the input/output interface circuit, and a metal reed is added on the connector to enhance the shielding effectiveness, but these measures can greatly increase the cost, and the metal reed is inconvenient to install and operate, and is not conducive to automatic generation. The invention can greatly reduce the electromagnetic radiation emission of the electronic control unit and improve the anti-interference capability on the premise of hardly increasing the cost.

In addition, as shown in fig. 5, the present application also provides a method for improving electromagnetic compatibility of an electronic control unit, and since the technical principle of the embodiment of the method is the same as that of the electronic control unit, the same technical details will not be repeated herein. The method of the embodiment comprises the following steps:

s10: dividing a ground of a circuit board of the electronic control unit into an interface ground and a logic ground;

s20: the ground of the input/output interface connector of the electronic control unit is taken as an interface ground, and a part of the shell ground is regarded as being connected with the metal shell of the electronic control unit.

In an embodiment, the method further comprises: and a plurality of shielding mechanisms are arranged at the interface ground and the logic ground and on one side close to the interface ground, and convex parts matched with the shielding mechanisms are arranged in the upper cover of the metal shell, so that after the upper cover and the lower cover of the metal shell are connected, the convex parts are in close contact with the shielding mechanisms.

In an embodiment, the method further comprises: providing a bridge for a high frequency input-output line across said interface ground and said logic ground for providing a continuous path for return current for a signal line; and connecting the low-frequency input and output line crossing the interface ground and the logic ground with an input and output interface connector of the electronic control unit through a signal line and a ground line.

In summary, the electronic control unit and the method for improving electromagnetic compatibility applied by the electronic control unit of the invention effectively overcome various defects in the prior art, and have high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. An electronic control unit, characterized in that,

The ground of the circuit board of the electronic control unit is divided into interface ground and logic ground;

The ground of the input and output interface connector of the electronic control unit is used as the interface ground, which is connected with the metal casing of the electronic control unit as a part of the casing ground.

2 . The electronic control unit according to claim 1 , wherein a plurality of shielding mechanisms are provided on the side where the interface ground and the logical ground are separated and close to the interface ground; The cover is provided with convex parts matching the plurality of shielding mechanisms; after the upper cover and the lower cover of the metal shell are connected, the convex parts are in close contact with each of the shielding mechanisms.

3 . The electronic control unit according to claim 2 , wherein the plurality of shielding mechanisms are arranged in a straight line and are evenly distributed on one side of the interface ground. 4 .

4 . The electronic control unit according to claim 1 , wherein the interface ground and the logic ground are connected through a bridge at a preset position. 5 .

5 . The electronic control unit according to claim 4 , wherein a bridge is provided corresponding to the high-frequency input and output lines that span the interface ground and the logic ground, so as to provide a continuous path of return current for the signal line. 6 . .

6. A method for improving the electromagnetic compatibility of an electronic control unit, comprising:

dividing the ground of the circuit board of the electronic control unit into interface ground and logic ground;

7 . The method according to claim 6 , further comprising: arranging a plurality of shielding mechanisms on a side where the interface ground and the logical ground are divided and close to the interface ground, and on the metal casing. 8 . The upper cover of the metal casing is provided with convex parts matching the plurality of shielding mechanisms, so that after the upper cover and the lower cover of the metal casing are connected, the convex parts are in close contact with each of the shielding mechanisms.

8. The method of claim 6, further comprising:

A bridge is provided for the high-frequency input and output lines crossing the interface ground and the logic ground, so as to provide a continuous path for the return current for the signal line;

The low-frequency input and output lines that cross the interface ground and the logic ground are connected to the input and output interface connectors of the electronic control unit through signal lines and ground lines.

9. A domain controller, characterized in that,

The ground of the circuit board of the domain controller is divided into interface ground and logic ground;

The ground of the input/output interface connector of the domain controller is used as the interface ground, which is connected with the metal casing of the domain controller as a part of the casing ground.

10 . An electronic device, characterized by comprising: the electronic control unit according to any one of claims 1 to 5 , or the domain controller according to claim 9 . 11 .