An On-Board-Type Micro-Switching Converter with MHz Band-Operation

This paper describes the high-frequency characteristics of a multilayered planar transformer consisting of two planar coils and Co-Fe amorphous magnetic films. The parameters of transformer operation obtained by finite element method (FEM) calculations are compared with measured values. The analysis shows that characteristic evaluation is useful for a simple understanding of the operation of a transformer. For a more precise analysis, the resonance in the windings must be considered. The application of the transformer to a resonant switching converter is also discussed. A high efficiency of 49.5% is obtained at a switching frequency of 6 MHz.