Model of high-efficiency high-current coupled inductor two-phase buck converter

This paper proposes a study and design considerations on a high-current high-efficiency two-phase buck converter with a coupled inductor. The converter operates close to the megahertz range. A specialized simulation model of the considered two-phase buck converter is proposed. The model allows an evaluation of current and voltage ripples at various duty cycles and inductor coupling factors. It can facilitate the design and tuning of such DC-DC converters. The model is implemented into a general-purpose simulation environment. The simulation results are presented and analyzed. The model is verified trough a dedicated experiment on a realized converter. Although coupled inductors increase the power converter efficiency, for high-current buck converter this effect is substantial at duty cycle bigger than 40 %. The advantages at lower duty cycle are related to the output voltage ripple and feedback response time. Design considerations are derived based on the analyzed simulation and experimental results of the investigated two-phase buck converter.