Effect of output capacitor ESR on dynamic performance of voltage-mode hysteretic controlled buck converter

Abstract

Different types of capacitors have different parameters, e.g. equivalent series resistance (ESR) and capacitance. In switching DC-DC converters with voltage-mode (VM) hysteretic control, the output capacitor ESR has a significant effect on dynamic performance. In this reported work, two critical conditions of the output capacitor ESR for mode shifting and normal operation of the VMhysteretic controlled buck converter are derived. These results, verified by circuit simulations, illustrate that the larger output capacitor ESR is necessary for the converter operating normally; otherwise, the converter operates abnormally. © The Institution of Engineering and Technology 2013.