Design and implementation of high frequency buck converter using multi-layer PCB inductor

Increasing the switching frequency for switch mode power supplies is one of methods to achieve smaller, lighter weight and cheaper power converters. This work investigates the opportunity of using two layer circular spiral inductors implemented in a 150 μm finished thickness printed circuit board for a high frequency DC-DC converter. The inductor was tested in a 5 W buck converter switching at 10 MHz. The converter achieved 84.7% peak efficiency converting 12 V to 5 V and 78% efficiency converting 24 V to 5 V.

I. Introduction

From the early beginning of using switch mode power supplies, it was obvious that the higher the switching frequency, the smaller the converters will be. Efficiency and thermal penalties were the limiting parameters for pushing the switching frequency to higher values. To develop such small power converters new semiconductor materials, innovative packaging, high frequency (300 KHz–30 MHz) magnetics and development of converter topologies are the pillars for achieving efficient power conversion. It was clear that silicon switches have a lot of limitations when used in high switching frequency converters especially at elevated input voltages. Gallium nitride (GaN) based converters have shown a boost in converter efficiencies due to their lower parasitic capacitances and improved figure of merits [1], [2]