Buck变换器是最常用的变换器，工程上常用的拓扑如正激、半桥、全桥、推挽等也属于Buck族，其中Buck变换器补偿网络设计，是开关电源的重要研究课题，本文将针对基于PI控制方式的4A开关电源进行设计和Multisim的仿真研究。-Buck converter is the most commonly used converter on the topology of the project, such as forward, half bridge, full bridge, push-pull, the Buck family, Buck Converter compensation network design is an important research topic of the switching power supply, this paper4A-based PI control switching power supply design and Multisim simulation study