LED drive power PCB design skills and specifications

LED drive power PCB design skills and specifications

In any power supply design, the physical design of the PCB board is the last link. Its design method determines electromagnetic interference and power supply stability. Let's analyze these links in detail:

First, establish the component parameters from the schematic diagram to the PCB design process-"input principle netlist-"design parameter settings-" manual layout-"manual wiring-" verification design-"review-" CAM output.

Second, the parameter setting The spacing between adjacent wires must meet electrical safety requirements, and in order to facilitate operation and production, the spacing should also be as wide as possible. The minimum spacing must be at least suitable for withstand voltage. When the wiring density is low, the spacing of the signal lines can be appropriately increased. For high and low level signal lines, the distance should be as short as possible and the spacing should be increased. In general, Set the trace spacing to 8mil. The distance from the edge of the inner hole of the pad to the edge of the printed board should be greater than 1mm, so as to avoid pad defects during processing. When the trace connected to the pad is thin, the connection between the pad and the trace should be designed as a water drop. This has the advantage that the pad is not easy to peel, but the trace and the pad are not easy to disconnect.

Third, the component layout practice has proved that even if the circuit schematic design is correct and the printed circuit board is not designed properly, it will also adversely affect the reliability of electronic equipment. For example, if the two thin parallel lines of the printed board are close together, it will form a delay of the signal waveform and form reflected noise at the end of the transmission line; interference caused by poor consideration of the power supply and ground wire will make the product Performance is degraded, so when designing printed circuit boards, you should pay attention to the correct method.

4. The high-frequency signal is included in the wiring switching power supply. Any printed wire on the PCB can function as an antenna. The length and width of the printed wire will affect its impedance and inductive reactance, thus affecting the frequency response. Even printed wires that pass DC signals can couple to RF signals from adjacent printed wires and cause circuit problems (even radiating interfering signals again).

5. After checking the wiring design, it is necessary to carefully check whether the wiring design conforms to the rules formulated by the designer, and also to confirm whether the established rules meet the requirements of the printed board production process. Generally, the wire and wire are welded. Whether the distance between the disk, the wire and the through hole, the component pad and the through hole, and the through hole and the through hole are reasonable and meet the production requirements. Whether the width of the power cord and the ground wire is appropriate, and whether there is any place in the PCB that can widen the ground wire. Note: Some errors can be ignored. For example, part of the outline of some connectors is placed outside the board frame, and errors will occur when checking the spacing. In addition, each time the traces and vias are modified, the copper must be re-coated once.

Sixth, according to the "PCB checklist", the content includes design rules, layer definitions, line widths, spacing, pads, and via settings. It is also important to review the rationality of the device layout, the routing of power and ground network, high speed Clock network routing and shielding, placement and connection of decoupling capacitors, etc.