Study the effect of input filter for buck converter

Abstract

Small signal model of current-controlled mode DC-DC buck converter is studied using small signal block diagrams. Input filter reduces the electromagnetic interference (EMI) of power input of converter and improves the performance of load. However, input filter added to reduce the electromagnetic interference will changes the system transfer function, which may create instability in the converter. Therefore, input filter should be such that it will reduce the electromagnetic interference as well as it should not induce any negative effect on current-controlled mode DC-DC converter.