浅析一款USB充电电源的EMC改善方法

An EMC Improvement Method for A USB Charging Power Supply is Analyzed

本文以一款30 W的USB充电电源入手,将电路划分为市电输入电路、EMI滤波电磁抗干扰电路、桥堆整流滤波电路、功率变压器、RCD高压吸收电路、PWM IC开关控制电路、次级整流电路、RC滤波与电压输出电路、反馈补偿电路九部分,对于电磁兼容性设计与测试问题进行分析,简述电磁兼容性的避免方式。本文提供的方案能够实现电路中电磁干扰的抑制,让转换器安全使用。

Starting from a 30 W USB charging power supply,this paper divides the circuit into nine parts:mains input circuit,EMI filter electromagnetic anti-interference circuit,bridge stack rectification and filter circuit,power transformer,RCD high-voltage absorption circuit,PWM IC switch control circuit,secondary rectifier circuit,RC filter and voltage output circuit,and feedback compensation circuit.The scheme presented in this article can suppress electromagnetic interference in the circuit and allow the converter to be used safely.