Patent ID: 7358788

Claim:
A switching circuit device, comprising: a compound semiconductor substrate; a first switching portion formed on the substrate and receiving a first control signal; a second switching portion formed on the substrate and receiving a second control signal that is a reversal of the first control signal; a logic circuit formed on the substrate and comprising an inverter connected with a power supply terminal, a control terminal and a ground terminal, the logic circuit receiving the first control signal through the control terminal, inverting the first control signal using the inverter to produce the second control signal, supplying the first control signal to the first switching portion and supplying the second control signal to the second switching portion; and a protecting element formed on the substrate and connected between the control terminal and the ground terminal, the protecting element comprising a first conduction region, a second conduction region and an insulating region that is disposed between the first and second conduction regions so as to provide a current path for surge protection, wherein the logic circuit further comprises a capacitor comprising an upper electrode and a lower electrode that is formed on the substrate, and the first conduction region is disposed adjacent the lower electrode so that a direct current flows between the lower electrode and the first conduction region.