FIG. 4 depicts another illustrative embodiment wherein a pair of converters CV] and CV2 are provided with primary coils ml and mg of transformers T1 and T2 being connected in series circuit. DC voltage Vin is potential divided by means of capacitors C10 and C20
and then the divided voltages are delivered to the primary coils through respective switching transformers Q1 and Q2. The secondary coils of the transformers T1,T2 are connected in parallel circuit