A DC-DC converter including a transformer having a primary-side winding and a secondary-side winding with a center tap, and a storage choke. A rectifier circuit is connected to each of the taps at the ends of the secondary-side winding and generates a rectified output voltage at a second output of said DC-DC converter. A snubber circuit is switched via the rectifier circuit and stores energy occurring in said rectifier circuit. (An actuation apparatus includes a switching time determining device designed to determine a time interval as a function of the output voltage, the charge stored in the snubber circuit and the current fluctuations of the current through the storage choke occurring as a result of the rectification. A storage signal generator generates an actuation signal for discharging the snubber circuit as a function of the determined time interval.