The invention relates to a DC converter (1) comprising: a first half-bridge circuit (2); a second half-bridge circuit (3); at least one transformer (4) having at least one primary winding (4a, 4b) and at least one secondary winding (4c, 4d), the first and second half-bridge circuit being designed to generate an alternating voltage in the at least one primary winding; an output connection (6) having a rectifier circuit (5), said output connection having a first output connection pole (6a) and a second output connection pole (6b); and at least one rectifier element (7, 8). The rectifier circuit is designed to rectify an applied voltage in the at least one secondary winding and to output said voltage at the output connection. The rectifier circuit has a reverse polarity protection transistor (9), the collector-emitter section or drain-source section of which is inserted between a connection of the at least one rectifier element and the first or second output connection pole of the output connection.