State of the Art in DC-to-DC Converters

A survey on the state of the arts in the dc-to-dc converter is presented. A number of important problems underlying the converter are classified into two categories, one is solvable by the averaging method and the other is not. In general, the converter circuit itself should be stable in order to reduce the size of the converter by making its switching frequency high. As examples of size reduction, we show three kinds of converter circuit techniques in which magnetics plays a key role. The first deals with a high frequency magnetic amplifier to suppress the current surge in high speed switching, the second with a ferro-resonant circuit driven by a high frequency inverter and the third with a high frequency converter of megahertz order which is based on a multi-vibrator. In these examples, we show that the amorphous core is effectively used for magnetic components.