A New Micro-Switching Regulator Using a Planar-Type Magnetic Core

The operation of a new micro-switching regulator using a planar-type magnetic core is described. The planar-type micro-magnetic core consists of Co-Zr amorphous magnetic films and zigzag-pattern coils, and is used as the main transformer in the switching regulator. When the core is driven at the parallel resonance frequency of the inductance and the stray capacitance of the coil, highly efficient regulator operation is expected, because the core loss is reduced when using a constant-voltage power supply. At a driving frequency of 1 MHz, the output and efficiency are 0.54 W and 30% respectively. Excellent voltage regulation is also achieved over a wide load-current range.