Abstract: A DC-DC converter circuit particularly for use in a photographic flash light emitting device for producing high DC voltage from a low DC voltage such as a battery. Heretofore, the converter transformer of such a circuit has three coils, i.e. a primary coil to be connected to a low DC source, a secondary coil to produce high voltage and a feedback coil for feeding feedback current to the base of a chopping transistor. The purpose of this invention is to eliminate the need for a feedback coil by feeding current from said high voltage in the secondary coil to the base of a transistor.