Monolithic Magnetic Modules for DC-DC Power Converters

Abstract
Advances in planar magnetic technology have resulted in the development of high speed, high power density, magnetic components for use in electrical power converters. In particular, the use of such components will result in a substantial reduction in transformer and inductor volumes, and will encourage development of low-profile, lightweight, efficient power converters that conform readily to printed circuit topologies. This paper describes a single, plasma-spray fabrication process, which overcomes many of the problems associated with integration of components produced by multiple manufacturers. The feasibility of monolithic magnetic technology has been shown by integrating all the magnetic components of a 100 Watt, 1 MHz, DC-DC forward converter into a single, monolithic, non-magnetic module, 51mm x 51mm x 5mm. The process involves plasma deposition of variable-permeability, ultra-low-loss, substituted ferrites that serve as cores for magnetic components. Non-magnetic regions of the modules serve as windings windows, inductor air gaps, isolations or as mounting substrate for other system components. The significance of the technology is its compatibility with semiconductor integrated circuitry, increased volumetric package efficiency, and reduction of overall manufacturing cost, size and weight of power electronic systems.