Patent ID: 8299842

Claim:
A bidirectional switch comprising: a semiconductor switch having a gate and main electrodes serving as a drain and a source, the semiconductor switch having a HEMT structure so that one of the main electrodes having a lower voltage than the other serves as a virtual source and the other main electrode as a virtual drain, and the semiconductor switch turning on/off in a manner of both directions upon receiving a gate signal between the gate and the virtual source; an overvoltage protection circuit connected between the virtual drain and gate of the semiconductor switch and having a resistor and a constant voltage diode; a first diode having a cathode connected to the virtual drain of the semiconductor switch and an anode connected to an end of a gate signal generator; and a second diode having an anode connected to the end of the gate signal generator and the anode of the first diode and a cathode connected to the virtual source of the semiconductor switch, wherein the overvoltage protection circuit includes a series circuit having a third diode, the resistor, and the constant voltage diode.