Preface
With the development of new energy intelligent network technology, automotive design is no longer the conventional 12V system, on the one hand 380V and other high voltage appear, on the other hand in the integrated circuit 1.3V and other more low voltage appear. At the same time the design process of power supply chips no longer only use LDO, the use of Buck and Boost power supply increases. This article will take a power supply PCB board as an example to analyze the common problems in the design of power supply PCB board, and hope to introduce some ideas for you to solve the EMC problems of power supply module.
01 Design Question.
A hardware engineer designed and completed a power supply board PCB as shown in the figure below. This board was found to have a large number of EMC problems and hidden problems during the EMC design review, and needs to be reworked, otherwise it will face great EMC risks. Problem 1:The interface filter parts are too far from the interface
Problem 2: The interface filters are not arranged vertically in columns.
Problem 3:The power filter pieces are not arranged together
Problem 4: Switching power supply input and output circuit is too large
02 Design ideas.
Switching power supply board in PCB wiring control the input rectifier filter loop, power loop, output rectifier loop, output filter loop loop loop area, loop to be small, wiring to be short!
03 Rectification design.
EMCLayout design points Sensitive signals away from high-current signals, especially frequency signals, and do not parallel alignment. Current circuit alignment as small as possible. Analog ground, power ground need to be separated, can be connected together through the hole or star point. Multiple IC power supply, can be connected in parallel single point ground to reduce crosstalk. The control circuit is separated from the power circuit. Decoupling capacitors need to be placed close to the IC power Pin. Power supply do a good job of multi-order filtering, smaller capacitors near the chip Pin. Anti-reverse, clamp protection devices placed near the connector. Do a good job of isolation design of high-voltage ground low-voltage ground Pay attention to the spacing of the safety regulation alignment
