Ferrite Inductor Models for Switch-Mode Power Supplies Analysis and Design

This paper discusses some models useful to analyze ferrite inductors operating in partial saturation in Switch-Mode Power Supplies (SMPSs). Inductance vs current curves are needed to assess if the level of saturation is sustainable for the inductor, in order to achieve SMPS volume reduction. The models discussed in the paper are generated from experimental voltage and current waveforms of the inductor in SMPSs. Two dual approaches are presented, based on the local and global characterization of the inductor under small- and large-amplitude current ripple conditions. The resulting curves provide inductor current prediction in agreement with experimental data.