Feasible Evaluations of Coupled Multilayered Chip Inductor for POL Converters

摘要

Point of load (POL) converters require a small size and high-efficiency performance for IT industrial applications. In addition, the interleaved technique, magnetic integration, and application of GaN FETs are well known as good approaches to satisfy these demands in the power converters. Although coupled inductors for POL converters have been proposed in several studies, a coupled multilayered chip inductor has not been examined because of the difficulty of its construction. In this paper, a novel coupled multilayered chip inductor for interleaved POL converters is proposed. This novel coupled inductor has a pair of windings with inverse coupling in the magnetic core. Further, the magnetic material of the coupled inductor is an Fe-based metal composite powder (Fe-Si-Cr). Additionally, an Fe-based powder in the magnetic core has been processed with electrical insulation by a highly crystallized oxide nanolayer in order to reduce the eddy-current losses. Finally, the high efficiency performance of the coupled multilayered chip inductor is evaluated by prototypes of interleaved buck converters using normally off-type GaN FETs with a switching frequency of 1MHz.