工作于临界模式的SEPIC拓扑的分析和设计

摘要

The SEPIC topology of the DC-DC topology can work in passive voltage step-up or step-down mode.It has some desirable characters： small current harmonic wave,restraining in-rush current,and low electromagnetic-interface（EMI）.Few paper present the analysis and modeling in detail on SEPIC topology.This paper makes a detail analysis on SEPIC topology operating in critical current mode,and simplified design procedure is given.At last a SEPIC converter is designed according to the specification,and the simulation result is given.%应用于DC-DC变换器的传统拓扑中SEPIC（Single-Ended Primary Inductance Converter）拓扑既可以用于升压又可以用于降压,并且输出电压为正电压,具有启动时限制浪涌电流、较小输入电流纹波和低电磁干扰（Electromagnetic Interference,EMI）,具有谐波小等优点,但针对SEPIC拓扑的详细分析和建模相对较少,文中针对工作于电流临界模式（Critical Current Mode,CRM）的SEPIC线路进行了详细的分析,并对理论等式进行了详细推导,给出了简化的设计步骤,最后根据要求对SEPIC变换器进行了设计,并给出了仿真波形.