Volumetric limits of planar integrated resonant transformers: a 1 MHz case study

Integrated planar resonant/transformer structures analysed are constructed from planar ferrites, conductive layers, leakage layers and slabs of ceramic dielectric. The minimum dimensions for these structures are determined based on electromagnetic and technological limits respectively. The electromagnetic limits are analysed in terms of the permeabilities, permittivities and conductivities, skin effect, breakdown field and physical dimensions. An example of a power converter with an integrated resonant/transformer (L-L-C-T) structure is used to illustrate the analysis. This analysis indicates that the electromagnetic limits results in volumes two orders of magnitude smaller than the present constructions, illustrating that the power density is at present only limited by constructional technology. The thermal limit is expected to be the next barrier within one order of magnitude