The invention relates to a switched-mode power supply (10) for converting an electric input variable (Ue) into an output variable (Ua), said supply comprising at least one inductance (L), which can be switched against an achievement potential (3,5) or a reference potential (4,6) using several switches (a-d). The switching losses of the converter (10) can be substantially reduced if at least one switch (a-d) is only activated in a zero-voltage mode.