Orthogonal Winding Structures and Design for Planar Integrated Magnetics

This paper presents a new winding design and implementation method for planar integrated magnetics (IM) to achieve high efficiency and high power density. The proposed design uses transformer and inductor windings that are orthogonal to each other in their plane orientations to minimize the capacitive coupling between them, as well as to reduce the thickness and the number of layers of the printed circuit board that hosts the windings. The orthogonal winding structures also result in lower dc resistance of the vertical winding and significantly reduce its eddy current losses. Applications of the proposed concept are demonstrated by an IM design for a 48-V-input 3.3-V-output 100-W half-bridge dc-dc converter with an integrated current-doubler rectifier. Finite-element analysis and prototype experimental results are presented to validate the proposed concept and its benefits.