A 3-D GaN-Based PoL Converters Based on the Planar Magnetic Component With Distributed Air Gap and High Thermal Conductivity

Abstract

The emerging gallium nitride devices have smaller footprints and lower switching loss, which are promising candidates for point-of-load (PoL) converters. The reduction in the core loss density of high-frequency ferrite materials reaches a bottleneck, which, however, makes it difficult to further reduce the cross area of the magnetic core. The planar inductor becomes the highest component in many PoL converters. This article presents 3-D GaN-based PoL converters, which feature an integrated magnetic component using an alloy powder core. The novel integrated magnetic component has a distributed air gap, lower core loss, and higher thermal conductivity, improving efficiency and thermal performance for PoL converters. This article analyzes the parasitic, magnetic design, and thermal characteristics of magnetic components in detail. A 90 W, 12–1.8 V prototype of a four-phase PoL converter based on ferrite magnetic core and proposed magnetic component using alloy material is built, compared, and tested. The experimental results show that the 3-D PoL converter based on a proposed magnetic component with a distributed air gap can achieve lower parasitic parameters, higher efficiency, and excellent thermal performance compared with a ferrite magnetic core.