A configurable DC-DC converter circuit has first and second DC voltage connections. The first DC voltage connection connected to a plurality of galvanically isolating DC-DC converters via a configuration circuit that has first and second switches, between which a changeover switch connects the first and second switches to one another via a diode device and connects the first and second switches to one another via a resistor. The DC-DC converters connected to the first and second switches. In the first changeover switch position, the first and the second switch are closed in a first configuration position and connect the DC-DC converters in parallel with one another. If the changeover switch is in the first switching position, the first and second switches, in a second configuration position in which the first and the second switches are open, the DC-DC converters are connected in series with one another via the diode device.