US Patent 7595680 Bidirectional switch and method for driving the same

A bidirectional switch includes a field-effect transistor having a first ohmic electrode, a second ohmic electrode and a gate electrode, and a control circuit for controlling between a conduction state and a cut-off state by applying a bias voltage to the gate electrode. The control circuit applies the bias voltage from the first ohmic electrode as a reference when a potential of the second ohmic electrode is higher than the potential of the first ohmic electrode, and applies the bias voltage from the second ohmic electrode as a reference when the potential of the second electrode is lower than the potential of the first ohmic electrode.