PFM controller with phase lead characteristics using hysteretic comparator for LLC converter

Abstract

This paper proposes a novel PFM controller for LLC converter. The proposed controller employs a hysteretic comparator and has phase lead characteristic, which improves system stability and the transient performance. Steady state and frequency characteristics of the proposed circuit are analyzed and confirmed by experiments. Since the proposed method does not need to use high GBW O.P.Amp., it becomes simple and low cost power supply.