Circuit arrangement having a voltage converter having an input path which is suitable for providing an input voltage (U IN ) to the voltage converter, an output path which is suitable for tapping off an output voltage (U OUT ) from the voltage converter, wherein the voltage converter at least three phases connected in parallel and each having at least one half-bridge in connection with a coil and a capacitor , or having at least two phases connected in parallel and each having at least two half-bridges in connection with a coil and a capacitor , wherein a fuse and a MOSFET are arranged in each branch of the half-bridges , a. characterized b. in that the circuit arrangement has a first switch arranged in series in the input path of the voltage converter and/or a second switch arranged in series in the output path of the voltage converter , and wherein the circuit arrangement is configured c. to identify a defect of a low-side MOSFET or a defect of a high-side MOSFET in a branch of a half-bridge of a phase , and d. to stop the actuation of all MOSFETs , and e. to open the second switch in the case of a defect of one of the low-side MOSFETs , or to open the first switch in the case of a defect of one of the high-side MOSFETs , and f. to actuate the MOSFETs of the phases in which all MOSFETs are intact in such a way that a sufficiently large current flows into the phase with the defect in order to trip the fuse . at least three phases connected in parallel and each having at least one half-bridge in connection with a coil and a capacitor , or having at least two phases connected in parallel and each having at least two half-bridges in connection with a coil and a capacitor , wherein a fuse and a MOSFET are arranged in each branch of the half-bridges , a. characterized b. in that the circuit arrangement has a first switch arranged in series in the input path of the voltage converter and/or a second switch arranged in series in the output path of the voltage converter , and wherein the circuit arrangement is configured c. to identify a defect of a low-side MOSFET or a defect of a high-side MOSFET in a branch of a half-bridge of a phase , and d. to stop the actuation of all MOSFETs , and e. to open the second switch in the case of a defect of one of the low-side MOSFETs , or to open the first switch in the case of a defect of one of the high-side MOSFETs , and f. to actuate the MOSFETs of the phases in which all MOSFETs are intact in such a way that a sufficiently large current flows into the phase with the defect in order to trip the fuse . a. characterized b. in that the circuit arrangement has a first switch arranged in series in the input path of the voltage converter and/or a second switch arranged in series in the output path of the voltage converter , and wherein the circuit arrangement is configured c. to identify a defect of a low-side MOSFET or a defect of a high-side MOSFET in a branch of a half-bridge of a phase , and d. to stop the actuation of all MOSFETs , and e. to open the second switch in the case of a defect of one of the low-side MOSFETs , or to open the first switch in the case of a defect of one of the high-side MOSFETs , and f. to actuate the MOSFETs of the phases in which all MOSFETs are intact in such a way that a sufficiently large current flows into the phase with the defect in order to trip the fuse . <EOS>