Abstract: A DC-DC converter converts an incoming unstabilized D.C. voltage to three stabilized output D.C. voltages. The converter contains two chopper stages (1, 2) with associated transformers, rectifiers (3, 4, 17a, 17b) and smoothing filters (5, 6, 18). The two chopper stages give a first and a second pulse-formed output voltage (U.sub.a and U.sub.b) which are regulated by shifting the leading edge of the pulses in the first output voltage (U.sub.a), while the second output voltage (U.sub.b) is regulated by shifting the trailing edge of the pulses. Two output voltages (U.sub.1, U.sub.2) are obtained after recitfying and smoothing. The third output voltage is obtained by connecting in parallel the outputs of two full-wave rectifiers (17a, 17b) which are magnetically coupled to the outputs of the two chopper steps, and by connecting a smoothing filter (18) to the common output of both full wave rectifiers. Regulation of the third output voltage (U.sub.