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 is the last link. The design method determines the electromagnetic interference and power supply stability. Let's analyze these links in detail:

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

3. The practice of component layout proves that even if the circuit schematic design is correct and the printed circuit board is not designed properly, it will adversely affect the reliability of electronic equipment. For example, if two thin parallel lines of a printed board are close to each other, a signal waveform delay will be formed, and reflection noise will be formed at the end of the transmission line; interference caused by inadequate consideration of the power supply and the ground line will cause the product's The performance is degraded. Therefore, when designing a printed circuit board, care should be taken to use the correct method.

Fourth, the wiring switching power supply contains high-frequency signals, 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, thereby affecting the frequency response. Even printed wires that pass a DC signal can couple from nearby printed wires to the RF signal and cause circuit problems (even radiating interference signals again).

Fifth, after checking the wiring design, you need to carefully check whether the wiring design conforms to the rules formulated by the designer. At the same time, you must also confirm whether the formulated rules meet the requirements of the production process of printed boards. Whether the distance between the disk, wire and through-hole, component pad and through-hole, through-hole and through-hole is reasonable and whether it meets the production requirements. Are the widths of the power and ground wires appropriate, and is there any place in the PCB to allow the ground wires to widen. Note: Some errors can be ignored. For example, part of the outline of some connectors is placed outside the board frame, which will cause errors when checking the spacing. In addition, after each modification of the wiring and vias, the copper should be re-coated once.

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