High-frequency eddy-current effects in low-profile transformer windings

A study of several configurations used to construct low-profile transformers is presented. Finite-element analysis is used to analyze the behavior of transformer current at high frequency and determine an appropriate winding configuration with low AC-resistance and leakage inductance. It is demonstrated that the foil structure is the most attractive winding configuration for low-profile transformer applications. As a result, a transformer with a height of 6 mm and a power density of 650 W/in/sup 3/ was built.