A circuit includes a first field-effect transistor and a second field-effect transistor. The first field-effect transistor includes a first diode with drain, source, gate and first additional electrodes. The second field-effect transistor includes a second diode with drain, source, gate and second additional electrodes. A first switch selectively connects the gate and drain electrodes of the first field-effect transistor. A second switch selectively connects the gate and drain electrodes of the second field-effect transistor. A control circuit controls the first and second switches. The first additional electrode is coupled to the gate electrode of the second field-effect transistor, and the second additional electrode is coupled to the gate electrode of the first field-effect transistor.