A high-frequency DC to DC converter comprising n transient converter circuits (1, 2 . . . n) operating in parallel. The converter has constant transfer characteristics, and the transient converter circuits are operated phase-shifted by 360°/n and with interleaved duty cycles, which results in a continuous energy transfer through the circuit. The circuit is also soft-switched, with very low switching losses. In particular, the active semiconductors only switch off a relatively small magnetization current, during a recovery phase which can last as long as (n−1)/n of the switching phase period.