Megahertz DC-to-DC converters controlled by an amorphous core

A compact DC-to-DC converter operating at megahertz region is constructed employing a very small amorphous core in the base drive circuit. The driving method of this converter is based on the transistorcore multivibrator, in which the current and the voltage feedback are combined. The multivibrator is synchronized with an external pulse, The amorphous core used is of two layers of a narrow Co-rich ribbon. Static characteristics are examined on the forward converter with this drive circuit. The efficiency of 81% is obtained with bipolar transistors at 1MHz.