Starting a DC/DC converter with high-frequency transformer

The method involves loading a primary winding (3) by clocked switches (V1,V2) having an inverter bridge (7) made of an input sided voltage intermediate circuit (5). The secondary winding (4) charges an outlet sided voltage intermediate circuit (16) by a rectifier bridge (15). The switches of the inverter bridge are clocked while starting up with a gradual fixed pulse width not more than 5 percent. An independent claim is also included for a direct current to direct current-converter with an operation mode.