Circuit board layout structure satisfying automobile electrical creep distance

Abstract

The utility model provides a circuit board layout structure satisfying automobile electrical creep distance, comprising a circuit board having a first area and a second area; electronic components of which the PIN spacing does not meet the preset spacing rule defined by the humidity condensation degree are placed in the first area; and the electronic components of which the PIN spacing meets the preset spacing rule defined by the humidity condensation degree are placed in the second area. The product development period can be shortened, the product development cost can be reduced, and the product process cost can also be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuit layout, and particularly relates to a circuit board layout structure that meets the creepage distance of automotive electrics. Background Art

[0002] In order to enhance the leakage current immunity strength in an electronic circuit such as a PCBA, when designing the PCB layout, it is required that there must be an insulation distance as large as possible between different voltage potentials. To improve the leakage current immunity strength of the PCBA, there must be an insulation distance as large as possible between different voltage potentials. The choice of the insulation distance should ensure that the PCBA is not affected electrically by moisture condensation. According to the requirements of VW80808, the minimum electrical creepage distance needs to be defined according to the humidity condensation degree HCG. Based on the creepage distance that needs to be met in VW80808 set by Volkswagen, it is very crucial to develop an efficient PCB Layout design method. According to the requirements of the humidity condensation degree in VW80808, the product needs to meet one of the following three categories:

[0003] HCG1: Moisture-proof protection measures (such as protective coatings, potting compounds, plastic molding compounds) must be used to prevent the circuit function from being damaged due to moisture condensation. The effectiveness of the protection measures must be recorded and documents must be provided as required. Other measures must be taken to prevent water from entering the protected electronic components.

[0004] HCG2: During the service life of the product, the PCBA is prohibited from exceeding the determined limit of ionic contamination. Other measures must be taken to prevent water from entering the PCBA (such as a waterproof housing with ventilation elements). For the PCBA, "in-vehicle salt spray test with operation" (according to VW80000, with the following deviation conditions: 1 test cycle, 2 devices under test, 2-hour spraying stage) and subsequent "damp heat cycle" (the test must be carried out according to VW80000) design verification are required. Subsequently, the dendritic growth of the PCBA and related components must be microscopically inspected.

[0005] HCG3: The situation where the ionic contamination level increases with the increase of humidity condensation conditions must be considered. For example, the electronic control unit (ECU) in a vehicle.

[0006] In view of the above, adopting the HCG1 technology requires the use of moisture-proof protection measures such as spraying a three-proof paint on the whole board, resulting in a high process cost for the product. The HCG2 technology requires salt spray and other test experiments under certain conditions, resulting in a long product development cycle and high development costs. The electrical spacing required by the HCG3 technology exceeds the package spacing of most electronic components on the market and cannot be applied to most products. Summary of the Utility Model

[0007] In view of the disadvantages of the above three technical solutions, the utility model provides a circuit board layout structure that meets the automotive electrical creep distance, which only solves the technical problems of long product development cycle and high cost in the prior art.

[0008] A circuit board layout structure that meets the electrical creep distance of an automobile includes a circuit board having a first area and a second area;

[0009] The first area is used to place electronic components whose PIN spacing does not meet the predetermined spacing rule defined by the humidity condensation degree;

[0010] The second area is used to place electronic components whose PIN spacing meets a predetermined spacing rule defined by the humidity condensation degree.

[0011] Furthermore, a conformal coating is applied to the first area.

[0012] Furthermore, the first area is arranged in the middle area of ​​the circuit board, and the second area is an area on the circuit board except the first area.

[0013] Further, the first area is set in the right area or the left area of ​​the circuit board, and the second area is the area on the circuit board except the first area.

[0014] Furthermore, the first region is provided with electronic components having a PIN spacing of less than 0.45 mm when the node voltage is between 0 and not more than 5 V;

[0015] The second area is used to place electronic components with a minimum PIN spacing of no less than 0.45 mm when the node voltage is within 0-5V.

[0016] Further, the first region is provided with electronic components having a PIN spacing less than 1.1 mm when the node voltage is greater than 5 V and less than 16 V;

[0017] The second area is used to place electronic components with a PIN pitch of no less than 1.1 mm when the node voltage is greater than 5 V and no greater than 16 V.

[0018] Further, the first region is provided with electronic components having a PIN spacing less than 1.9 mm when the node voltage is greater than 16 V and less than 60 V;

[0019] The second area is used to place electronic components with a PIN spacing of no less than 1.9 mm when the node voltage is greater than 16 V and no greater than 60 V.

[0020] Furthermore, the circuit board layout structure includes an LED driving circuit, the LED driving circuit includes a driving chip and at least one light emitting diode connected to the driving chip, the driving chip is placed in the first area, and the light emitting diode is placed in the second area.

[0021] Further, the LED driving circuit further includes a ground capacitor which is placed in the first area.

[0022] Further, the circuit board layout structure further includes a CAN transceiver circuit connected to the driving chip, and the CAN transceiver circuit is arranged in the second area.

[0023] The beneficial technical effects of the present utility model are as follows: by determining whether to meet the predetermined pitch rule, the electronic components involved in the circuit structure are divided into two categories. One category is concentratedly arranged in the predetermined first area, and the other category is arranged in the second area outside the first area. As long as protective measures are used in the first area, salt spray and other test trials are not required, which can shorten the product development cycle, reduce the product development cost, and at the same time can also reduce the product process cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1-2 It is a layout schematic diagram of a circuit board layout structure of the present utility model that meets the creepage distance of automotive electrics. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without any creative work belong to the scope of protection of the present utility model.

[0026] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other.

[0027] Next, the present utility model will be further described in conjunction with the drawings and specific embodiments, but it is not a limitation of the present utility model.

[0028] Refer to Figure 1 , the present utility model provides a circuit board layout structure that meets the creepage distance of automotive electrics, including a circuit board which has a first area (1) and a second area (2);

[0029] Electronic components with a PIN pitch that does not meet the predetermined pitch rule defined by the humidity condensation degree are placed in the first area (1);

[0030] Electronic components with a PIN pitch that meets the predetermined pitch rule defined by the humidity condensation degree are placed in the second area (2).

[0031] Specifically, the circuit board is a PCB (Printed Circuit Board) or a PCBA (Printed Circuit Board Assembly).

[0032] The electronic components involved in the circuit structure are divided into two categories according to whether a predetermined spacing rule is satisfied. One category is centrally arranged in a predetermined first region, and the other category is arranged in a second region outside the first region. As long as protection measures are used in the first region and no salt spray and other test trials are required, the product development cycle can be shortened, the product development cost can be reduced, and at the same time, the product process cost can also be reduced.

[0033] Further, a three-proof paint is applied to the first region (1).

[0034] Further, the first region (1) is arranged in the middle region of the circuit board, and the second region (2) is the region of the circuit board other than the first region (1).

[0035] Further, the first region (1) is arranged in the right region or the left region of the circuit board, and the second region (2) is the region of the circuit board other than the first region (1).

[0036] Further, electronic components with a PIN pitch less than 0.45 mm are placed in the first region (1) when the node voltage is between 0 and not greater than 5V;

[0037] Electronic components with a minimum PIN pitch not less than 0.45 mm are placed in the second region (1) when the node voltage is within 0 - 5V.

[0038] Further, electronic components with a PIN pitch less than 1.1 mm are placed in the first region (1) when the node voltage is greater than 5V and not greater than 16V;

[0039] Electronic components with a PIN pitch not less than 1.1 mm are placed in the second region (2) when the node voltage is greater than 5V and not greater than 16V.

[0040] Further, electronic components with a PIN pitch less than 1.9 mm are placed in the first region (1) when the node voltage is greater than 16V and not greater than 60V;

[0041] Electronic components with a PIN pitch not less than 1.9 mm are placed in the second region (2) when the node voltage is greater than 16V and not greater than 60V.

[0042] Specifically, the node voltage refers to the voltage difference between the input and output of an electronic component. That is, an electronic component is regarded as a node, and the voltage across this node is the node voltage.

[0043] Under different HCG conditions, the required electrical distances are as shown in Table 1 below:

[0044] Table 1 Electrical creepage distance requirements for different HCG conditions

[0045] Node voltage HCG1 (mm) HCG2 (mm) HCG3 (mm) 0V – ≤5V 0.10 0.25 0.45 5V – ≤16V 0.25 0.60 1.10 16V – ≤60V 0.45 1.20 1.90

[0046] The predetermined spacing rule defined by the humidity condensation degree refers to the spacing rules under different voltage ranges of HCG3. For example, under 0 - 5V, the PIN spacing should meet a spacing of more than 0.45mm. If the electronic components do not meet the requirements, they are in the first area; if they meet the requirements, they are in the second area.

[0047] That is to say, the electronic components that do not meet the HCG3 distance can include those that meet HCG1, or those that meet HCG2, or those that simultaneously meet HCG1 and HCG2. A separate first area is set, and a three-proof paint (waterproof, moisture-proof, dust-proof, etc.) is coated in the first area. In this way, for these devices, the three-proof paint is only coated in the concentrated first area, saving process costs. Moreover, it saves the salt spray and other test experiments for HCG2 technology under certain conditions, shortens the development cycle, and thus reduces the development cost and product process cost.

[0048] In the PCB Layout design stage, it can be carried out through the following steps:

[0049] Step 1: Statistically analyze the voltages of each node in the design and classify them to establish voltage categories. Each electronic component is regarded as a node, and the voltage categories can be divided into three major categories according to the voltages 0 - 5, 5 - 16, and 6 - 60 in Table 1 above.

[0050] Step 2: According to the voltage classification and the spacing requirements of HCG1 and HCG3 in the specification, screen out the electronic components that do not meet HCG3 for ROOM setting;

[0051] Step 3: According to the distance requirements of HCG1, HCG2, HCG3, etc. in VW80808, perform overall rule setting;

[0052] Step 4: After the rule setting is completed, perform PCB Layout wiring under the rule constraints to form the layout diagram of the circuit device.

[0053] After the layout diagram is completed, the circuit device can be formed through the process.

[0054] In the PCB Layout design, it provides the ideas required for layout and wiring to the Layout engineer, avoiding blindly arranging electronic components and not summarizing voltage differences, thereby reducing the PCB Layout design efficiency and causing waste of time and human resources.

[0055] Furthermore, the circuit board layout structure comprises an LED driving circuit, the LED driving circuit comprises a driving chip (3) and at least one light-emitting diode (4) connected to the driving chip (3), the driving chip (3) is placed in a first area (1), and the light-emitting diode (4) is placed in a second area (2).

[0056] The light emitting diode is electrically connected to the driving chip. Furthermore, the LED driving circuit also includes a ground capacitor (5), and the ground capacitor (5) is placed in the first area (1).

[0057] like Figure 2 As shown, a first area is set separately in the area near the lower left corner, the LED driver circuit, the module input voltage is 6.5V, greater than 5V. The driver chip package PIN spacing is 0.20mm, which cannot meet the HCG3 minimum spacing of 0.45mm. Therefore, the driver chip is set in the first area. Since the module input voltage is 6.5V, the voltage between the two pins of the surrounding ground capacitor is greater than 5V, and the capacitor itself does not meet the HCG3 voltage difference greater than 5V. The distance requirement of 1.1mm is also required. The ground capacitor is also set in the first area, and the driver chip and the ground capacitor are coated with three anti-paints together.

[0058] At least one light emitting diode is placed in the second area except the first area because it meets the HCG3 spacing requirement. Figure 2 It shows that the light emitting diodes are arranged in the second area, that is, to the right of the first area.

[0059] Furthermore, the circuit board layout structure also includes a CAN transceiver circuit (6) electrically connected to the drive chip (3), and the CAN transceiver circuit (6) is arranged in the second area (2).

[0060] For a car, the LED driving circuit needs to receive a driving control signal before it can start driving the light-emitting diode to emit light. Therefore, a CAN transceiver circuit is set on the circuit board to receive the driving control signal through the CAN line and send the driving control signal to the driving chip to drive the light-emitting diode to emit light.

[0061] The utility model has low design cost and high design safety, and solves the problem of creep distance that needs to be met in electronic product circuit boards, especially PCBA, in order to enhance the leakage current anti-interference strength.

[0062] The above are only preferred embodiments of the present invention, and do not limit the implementation mode and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A circuit board layout structure that meets the creepage distance requirements of automotive electrical systems, characterized in that, A circuit board is included, the circuit board having a first area and a second area; The first area is used to place electronic components whose PIN spacing does not meet a predetermined spacing rule defined by the humidity condensation degree; The second area is provided with electronic components whose PIN spacing satisfies a predetermined spacing rule defined by the humidity condensation degree; The first area is used to place electronic components with a PIN spacing of less than 0.45 mm when the node voltage is between 0 and no more than 5 V; The second area is used to place electronic components with a minimum PIN spacing of not less than 0.45 mm when the node voltage is within 0-5V.

2. The circuit board layout structure for meeting the creepage distance of automotive electrics as described in claim 1, characterized in that, A conformal coating is applied to the first area.

3. A circuit board layout structure that meets the creepage distance of automotive electrical appliances, characterized in that, The first area is arranged in the middle area of ​​the circuit board, and the second area is an area on the circuit board except the first area.

4. A circuit board layout structure that meets the creepage distance of automotive electrical systems, characterized in that, The first area is arranged in the right area or the left area of ​​the circuit board, and the second area is an area on the circuit board except the first area.

5. A circuit board layout structure for meeting the creepage distance of automotive electrics, characterized in that, The first area is used to place electronic components with a PIN spacing of less than 1.1 mm when the node voltage is greater than 5V and not greater than 16V; The second area is used to place electronic components with a PIN pitch of not less than 1.1 mm when the node voltage is greater than 5V and not greater than 16V.

6. A circuit board layout structure for meeting the creepage distance of automotive electrical appliances as described in claim 1, characterized in that, The first area is used to place electronic components with a PIN spacing less than 1.9 mm when the node voltage is greater than 16 V and less than 60 V; The second area is used to place electronic components with a PIN pitch of not less than 1.9 mm when the node voltage is greater than 16 V and not greater than 60 V.

7. A circuit board layout structure that meets the creepage distance of automotive electrical systems, characterized in that, The circuit board layout structure includes an LED driving circuit, and the LED driving circuit includes a driving chip and at least one light emitting diode connected to the driving chip. The driving chip is placed in the first area, and the light emitting diode is placed in the second area.

8. A circuit board layout structure for meeting the creepage distance of automotive electrics, characterized in that The LED driving circuit further includes a ground capacitor, and the ground capacitor is placed in the first area.

9. A circuit board layout structure that meets the creepage distance of automotive electrical systems, characterized in that, The circuit board layout structure further includes a CAN transceiver circuit connected to the driving chip, and the CAN transceiver circuit is arranged in the second area.

Images