Patent ID: 7872315

Claim:
A switching device for an electric circuit, comprising: (a) a pair of main terminals to which a voltage is to be applied; (b) a main control terminal for inputting a control signal; (c) an insulated-gate field-effect transistor for performing a switching function for the switching device, comprising: (i) a drain region of a first conductivity type; (ii) a body region of a second conductivity type formed contiguous to the drain region and having an exposed surface; (iii) a source region of the first conductivity type formed in the body region and having an exposed surface; (iv) a drain electrode disposed in ohmic contact with the drain region and electrically coupled to one of the pair of main terminals; (v) a source electrode disposed in ohmic contact with the source region and in Schottky contact with the body region and electrically coupled to the other of the pair of main terminals; (vi) a gate insulator covering the exposed surface of the body region between the source region and the drain region; and (vii) a gate electrode held against the exposed surface of the body region via the gate insulator; and (d) protector switch means for protecting the insulated-gate field-effect transistor by becoming conductive when a voltage oriented to reverse-bias the Schottky contact of the insulated-gate field-effect transistor is applied between the drain and source electrodes of the insulated-gate field-effect transistor, the protector switch means comprising: (i) a first main terminal connected to the drain electrode of the insulated-gate field-effect transistor; (ii) a second main terminal connected to the gate electrode of the insulated-gate field-effect transistor; and (iii) a control terminal.