Control follow-up PCB circuit for suppressing electromagnetic interference

Abstract

The invention relates to a control follow-up PCB circuit for suppressing electromagnetic interference, and belongs to the technical field of PCB circuits. The structure layout is compact, the partition is clear, the processing technology requirement is met, the processing cost of the printed board is reduced, electromagnetic interference is effectively inhibited, unnecessary interference coupling between printed circuits is reduced, and the reliability of a system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of PCB circuits, and in particular relates to a control follow-up PCB circuit for suppressing electromagnetic interference. Background Art

[0002] As the structure of electronic equipment becomes more and more complex, the functions become more and more diversified, and the performance requirements become higher and higher (increased power, high sensitivity, etc.), the interference problem becomes increasingly prominent, the electromagnetic environment becomes increasingly harsh, and it is difficult to prevent circuits from being affected by external electromagnetic interference.

[0003] Whether the PCB circuit is reasonable has a great impact on the anti-interference performance of the entire device. For the control and follow-up circuit that includes power supply, motor drive (high power), digital, analog and communication, the layout, wiring and power layer processing have a very important impact on the electromagnetic interference problem of the entire circuit. In the existing technology, the layout and wiring of the device are mostly analyzed from the perspective of circuit design, and the design is positioned based on previous design experience, which is largely uncertain. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The technical problem to be solved by the present invention is to design a control follow-up PCB circuit that can effectively suppress electromagnetic interference.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a layout and wiring partitioning method of a control and follower PCB circuit for suppressing electromagnetic interference. The control and follower PCB circuit includes a connector, a 0 ohm resistor, an FPGA, a DSP, a FLASH, an SDRAM, an isolation chip, an AD\DA, a power chip, a motor drive chip, an input analog signal circuit, a communication circuit, a magnetic bead, and a resistor and a capacitor; from a horizontal perspective, the control and follower PCB circuit is divided into four functional circuit areas, namely, a digital circuit area 1, a motor drive circuit area 2, an analog circuit area 3, and a communication circuit area 4; the power supply of the digital circuit area 1 is input by a connector, and then converted into a voltage for use by the digital circuit area 1 through a power chip; the power supply of the communication circuit area 4 is provided by the voltage supplied to the digital circuit area 1 after being isolated by an isolation chip; the power supply of the analog circuit area 3 is input by the input power supply of the digital circuit area 1 after being isolated by a 0 ohm resistor; the power supply of the motor drive circuit area 2 is also directly input by a connector.

[0008] Preferably, the isolation zone between the analog circuit area 3 and the digital circuit area 1, and between the digital circuit area 1 and the communication circuit area 4 is ≥20 mil, and the isolation zone between the digital circuit area 1 and the motor drive circuit area 2 is ≥40 mil, and all signal lines are laid in their respective areas.

[0009] Preferably, the digital circuit area 1, the motor drive circuit area 2, the analog circuit area 3, and the communication circuit area 4 are arranged in different areas according to the signal direction and the input and output of the power supply, wherein the FPGA, DSP, FLASH, SDRAM, power chip, and part of the AD\DA circuits all belong to the digital circuit part, and the wiring and power distribution are designed in the digital circuit area 1; the input analog signal circuit and part of the AD\DA circuits belong to the analog circuit, and the wiring and power supply are designed in the analog circuit area 3; the communication circuit is also part of the digital circuit, and the signal routing after the isolation chip is designed in each communication circuit area 4, and the adjacent plane layers are paved by the corresponding ground plane; the motor drive chip, magnetic beads, resistors and capacitors, and the motor control signal after the isolation chip all belong to the motor drive circuit part, and the wiring and power supply are designed in the motor drive circuit area 2.

[0010] Preferably, the components, wiring and vias on the control follower PCB circuit are 2mm away from the edge, and the inner electrical plane is 30mils inward compared to the ground plane as a whole; the decoupling capacitors of the power chip are evenly distributed around the corresponding voltage pins of the power chip, and stray signals of different frequencies are filtered out by different capacitance values.

[0011] Preferably, each plane layer is laid with ground plane and power plane according to the functional circuit area; the spacing between the ground / power plane of the motor drive circuit part and the digital ground / power plane is 40 mil, and the spacing between other ground / power planes is 20 mil.

[0012] Preferably, viewed from the longitudinal direction, the control and follow-up PCB circuit has a total of 10 layers, which are symmetrically stacked, among which layers 1, 3, 5, 6, 8, and 10 are signal routing layers, and layers 2, 4, 7, and 9 are plane layers, among which layers 5 and 6 are adjacent signal layers, and the wires are perpendicular or cross-routed to each other; each adjacent signal layer has a corresponding plane layer, and a complete ground plane is laid on the high-speed sensitive adjacent signal layer, and the corresponding high-speed signal wiring area is not divided, forming an interference shielding for the high-speed signal.

[0013] Preferably, the distances between the components, wirings and vias on the entire control-follow-up PCB circuit and the edge of the control-follow-up PCB circuit are greater than or equal to the thickness of the control-follow-up PCB circuit, and the distance between the inner electrical plane layer and the ground plane to the edge of the control-follow-up PCB circuit meets the 20H principle.

[0014] Preferably, the wiring of each layer of signals is completed according to the line width of the single line in the impedance stacking diagram, the line width and spacing of the differential signal line, and the line width of the power line, ground line and ground line are all ≥20mil; the routing impedance control in the control follow-up PCB circuit is designed according to 50 ohms for single-ended signal lines and 100 ohms for differential signal lines. The routing spacing between each signal meets the 3W principle, and the spacing between single-ended signal lines is ≥4mil.

[0015] Preferably, all differential pair signal lines are routed on the top layer or the bottom layer.

[0016] The present invention also provides a control follow-up PCB circuit designed based on the method.

[0017] (III) Beneficial effects

[0018] The structure of the present invention has a compact layout, clear partitions, and meets the processing technology requirements. While reducing the processing cost of the printed circuit board, it effectively suppresses electromagnetic interference, reduces unnecessary interference coupling between printed circuits, and improves the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the layout and wiring partition diagram of each circuit of the present invention;

[0020] Among them: 1 is the digital circuit area; 2 is the motor drive circuit area; 3 is the analog circuit area; 4 is the communication circuit area;

[0021] Figure 2 It is the plane layer partition diagram of the present invention;

[0022] Among them: 1 is the digital circuit area; 2 is the motor drive circuit area; 3 is the analog circuit area; 4 is the communication circuit area;

[0023] Figure 3 This is a stacked diagram of the impedance of the control follower PCB board of the present invention;

[0024] Among them: 301 is the laminate design of the printed circuit board; 302 is the signal line impedance control, line width and board thickness.

[0025] Figure 4 This is the interference shielding processing diagram of adjacent plane layers of communication differential signals;

[0026] Among them: 401 is the differential pair routing; 402 is the ground copper foil of the adjacent plane layer of the differential pair routing.

[0027] Figure 5 Route analog signals using shielded routing.

[0028] Among them: 501 is the VIDEO analog signal line; 502 is VIDEO_GND. DETAILED DESCRIPTION

[0029] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0030] The present invention provides a control follower PCB circuit for suppressing electromagnetic interference. In order to enable the present invention to effectively suppress electromagnetic interference, the present invention will be further described below in conjunction with the accompanying drawings of the present invention.

[0031] The present invention provides a control and follow-up PCB circuit layout and wiring partitioning method designed for suppressing electromagnetic interference. The control and follow-up PCB circuit includes a connector, a 0 ohm resistor, an FPGA, a DSP, a FLASH, an SDRAM, an isolation chip, an AD\DA, a power chip, a motor drive chip, an input analog signal circuit, a communication circuit, a magnetic bead, a resistor and a capacitor, etc. Figure 1 , Figure 2 From a horizontal perspective, the control and follow-up PCB circuit is divided into four functional circuit areas: digital circuit area 1, motor drive circuit area 2, analog circuit area 3, and communication circuit area 4. The power supply of digital circuit area 1 is input by the connector, and then converted into a voltage for use in digital circuit area 1 through the power chip; the power supply of communication circuit area 4 is provided by the voltage supplied to digital circuit area 1 after being isolated by the isolation chip; the power supply of analog circuit area 3 is input by the input power supply of digital circuit area 1 after being isolated by a 0 ohm resistor; the power supply of motor drive circuit area 2 is also directly input by the connector. Through the detailed division of the above functional areas, each circuit layout and wiring design can be clearly handled separately, there is no common ground impedance between circuits with different functions, and cross interference between lines in each area is avoided.

[0032] The isolation zone between the analog circuit area 3 and the digital circuit area 1, and between the digital circuit area 1 and the communication circuit area 4 is ≥20 mil. The electromagnetic interference of the motor drive circuit area 2 is relatively large. The isolation zone between the digital circuit area 1 and the motor drive circuit area 2 is ≥40 mil. All signal lines are laid in their respective areas.

[0033] Reference Figure 1, the digital circuit area 1, motor drive circuit area 2, analog circuit area 3, and communication circuit area 4 involved in the present invention are clearly divided into different areas according to the signal direction and the input and output of the power supply. Among them, FPGA, DSP, FLASH, SDRAM, power chip, and part of the AD\DA circuits all belong to the digital circuit part, and the wiring and power distribution are designed in the digital circuit area 1; the input analog signal circuit and part of the AD\DA circuit belong to the analog circuit, and the wiring and power supply are designed in the analog circuit area 3; the communication circuit is also part of the digital circuit. In order to ensure the anti-interference ability of this part of the signal routing, the signal routing after the isolation chip is designed in each communication circuit area 4, and the adjacent plane layers are laid by the corresponding ground plane; the motor drive chip, magnetic beads, resistors and capacitors, and the motor control signal after the isolation chip all belong to the motor drive circuit part, and the wiring and power supply are designed in the motor drive circuit area 2.

[0034] The components, wiring and vias on the control PCB circuit (printed board) are 2mm away from the edge of the printed board, and the inner electrical plane is 30mils inward compared to the ground plane to reduce the electromagnetic radiation of the ground layer and the power layer at the edge of the printed board.

[0035] Reference Figure 2 , each plane layer is laid out with ground plane and power plane according to the functional circuit area. The power ground and power power (the ground plane and power plane of the motor drive circuit part) have large radiation and electromagnetic interference, and the spacing between them and the digital ground (power) plane is 40mil, and the spacing between other ground (power) planes is 20mil.

[0036] Reference Figure 3 From a vertical perspective, the stacking of the control follower PCB circuit (printed board) is symmetrical with a total of 10 layers. Layers 1, 3, 5, 6, 8, and 10 are signal routing layers, and layers 2, 4, 7, and 9 are plane layers. Layers 5 and 6 are adjacent signal layers. To avoid crosstalk between signals, the wires are perpendicular or cross-routed. Each adjacent signal layer has a corresponding plane layer. The high-speed sensitive adjacent signal layer is paved with a complete ground plane, and the corresponding high-speed signal wiring area is not divided, forming an interference shield for the high-speed signal.

[0037] The distance between the components, wiring and vias on the entire control and follow-up PCB circuit and the edge of the control and follow-up PCB circuit is greater than or equal to the thickness of the control and follow-up PCB circuit. The distance between the inner electrical plane layer and the ground plane meets the 20H principle to reduce the electromagnetic radiation of the ground layer and the power layer at the edge of the printed circuit board, and avoid the metal burrs on the edge of the control and follow-up PCB circuit during processing causing a short circuit between the ground layer and the power layer. The decoupling capacitors of the power chip in the control and follow-up PCB circuit are evenly distributed around the corresponding voltage pins (power chip). Different capacitance values ​​are used to filter out stray signals of different frequencies. The capacitor leads are as short as possible to minimize the impedance and radiation loop of the coupling capacitor.

[0038] According to the line width of the single line in the impedance stacking diagram, the line width and spacing of the differential signal line, the wiring of each layer of signals is completed. The power line and the ground line should be as short and wide as possible. In general, the line width is ≥20mil to reduce the high-frequency loop area, thereby improving the circuit's anti-noise ability. The trace impedance control in the control follow-up PCB circuit is designed according to 50 ohms for single-ended signal lines and 100 ohms for differential signal lines. The trace spacing between each signal should meet the 3W principle as much as possible. In places with high wiring density, the spacing between single-ended signal lines should also be ≥4mil.

[0039] Reference Figure 4 All differential pair signal lines are routed on the top or bottom layer, avoiding vias and ensuring signal continuity. Adjacent signal layers are complete ground planes, which improves anti-interference performance.

[0040] Sensitive and key signals need to be shielded. The video analog signal line (routing between two connectors) in the present invention adopts shielding measures, without crossing with other signal lines, effectively isolating external interference and its interference to the outside, while ensuring the integrity of the signal. Figure 5 When VIDEO analog signal is routed, VIDEO_GND is used for outsourcing, in order to better reflux and isolate, so as to prevent crosstalk between signals. In the present invention, the VIDEO signal line is routed on the 5th layer, the adjacent 6th layer signal layer is not arranged with signal line, and the 4th layer signal layer is a complete ground plane, thereby ensuring the stability and quality of the signal.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A layout and wiring partitioning method for controlling and controlling a follow-up PCB circuit for suppressing electromagnetic interference, characterized in that: The control and follow-up PCB circuit includes a connector, a 0 ohm resistor, FPGA, DSP, FLASH, SDRAM, an isolation chip, AD\DA, a power chip, a motor drive chip, an input analog signal circuit, a communication circuit, a magnetic bead, and a resistor and a capacitor; from a horizontal perspective, the control and follow-up PCB circuit is divided into four functional circuit areas: a digital circuit area, a motor drive circuit area, an analog circuit area, and a communication circuit area; the power supply of the digital circuit area is input by the connector, and then converted into a voltage for use in the digital circuit area through the power chip; the power supply of the communication circuit area is provided by the voltage supplied to the digital circuit area after being isolated by the isolation chip; the power supply of the analog circuit area is input by the input power supply of the digital circuit area after being isolated by a 0 ohm resistor; the power supply of the motor drive circuit area is also directly input by the connector.

2. The method according to claim 1, characterized in that The isolation zone between the analog circuit area and the digital circuit area, and between the digital circuit area and the communication circuit area is ≥20mil, and the isolation zone between the digital circuit area and the motor drive circuit area is ≥40mil. All signal lines are laid in their respective areas.

3. The method according to claim 2, characterized in that Digital circuit area 1, motor drive circuit area, analog circuit area, and communication circuit area are divided into different areas according to the signal direction and the input and output of the power supply. Among them, FPGA, DSP, FLASH, SDRAM, power chip, and part of the AD\DA circuits belong to the digital circuit part, and the wiring and power distribution are designed in the digital circuit area; the input analog signal circuit and part of the AD\DA circuit belong to the analog circuit, and the wiring and power supply are designed in the analog circuit area; the communication circuit is also part of the digital circuit, and the signal routing after the isolation chip is designed in each communication circuit area, and the adjacent plane layers are paved with the corresponding ground plane; the motor drive chip, magnetic beads, resistors and capacitors, and the motor control signal after the isolation chip belong to the motor drive circuit part, and the wiring and power supply are designed in the motor drive circuit area.

4. The method according to claim 3, characterized in that The components, wiring and vias on the control follower PCB circuit are 2mm away from the edge, and the inner electrical plane is 30mils inward compared to the ground plane; the decoupling capacitors of the power chip are evenly distributed around the corresponding voltage pins of the power chip, and stray signals of different frequencies are filtered out by different capacitance values.

5. The method according to claim 4, characterized in that Each plane layer is laid out with ground plane and power plane according to the functional circuit area; the spacing between the ground / power plane of the motor drive circuit part and the digital ground / power plane is 40 mil, and the spacing between other ground / power planes is 20 mil.

6. The method according to claim 5, characterized in that From a vertical perspective, the control and follow-up PCB circuit has a total of 10 layers, which are symmetrical. Among them, layers 1, 3, 5, 6, 8, and 10 are signal routing layers, and layers 2, 4, 7, and 9 are plane layers. Layers 5 and 6 are adjacent signal layers, and the wires are perpendicular or cross-routed to each other; each adjacent signal layer has a corresponding plane layer, and the high-speed sensitive adjacent signal layer is paved with a complete ground plane, and the corresponding high-speed signal wiring area is not divided, forming an interference shielding for the high-speed signal.

7. The method according to claim 6, characterized in that The distance between the components, wiring and vias on the entire control and follow-up PCB circuit and the edge of the control and follow-up PCB circuit is greater than or equal to the thickness of the control and follow-up PCB circuit, and the distance between the inner electrical plane layer and the ground plane to the edge of the control and follow-up PCB circuit meets the 20H principle.

8. The method according to claim 7, characterized in that The wiring of each layer of signals is completed according to the line width of the single line in the impedance stacking diagram, the line width and spacing of the differential signal line. The line width of the power line, ground line and ground line are all ≥20mil; the routing impedance control in the control follow-up PCB circuit is designed according to 50 ohms for single-ended signal lines and 100 ohms for differential signal lines. The routing spacing between each signal meets the 3W principle, and the spacing between single-ended signal lines is ≥4mil.

9. The method according to claim 8, characterized in that All differential pair signal lines are routed on the top or bottom layer.

10. A control and follow-up PCB circuit designed based on the method as described in any one of claims 1 to 9.

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