A bidirectional flyback converter circuit includes a transformer with inductively coupled primary and secondary windings, primary-side and secondary-side switching elements, wherein the primary winding and secondary windings are respectively connected to a voltage input and output, where the primary-side and secondary-side switching elements are respectively arranged in series with the primary and secondary windings, where a charge capacitor is connected via a first terminal to a common potential of the primary and secondary sides, where with a second terminal, the charge capacitor is connected via a first diode to a common potential of the primary-side switching element and primary winding and via a second diode to a common potential of the secondary-side switching element and secondary winding, and where a buck converter is arranged on the input or output side, through which a voltage present at the charge capacitor can be regulated to a predeterminable value.