Semiconductor switching device utilizing bipolar and MOS elements

Claim 1

A semiconductor switching device comprising: a bipolar transistor having a collector electrode connected to a collector terminal of said switching device, a base electrode connected to a base terminal of said switching device, and a plurality of emitter electrodes; a plurality of MOS transistors wherein the number of said MOS transistors is the same as the number of emitter electrodes of said bipolar transistors, and wherein said MOS transistors each have a gate electrode coupled to a gate terminal of said switching device; first connection means for connecting each of the plurality of emitter electrodes of said bipolar transistor to a corresponding drain electrode of said MOS transistors; second connection means for connecting in common the source electrodes of said MOS transistors to an emitter terminal of said switching device; means for transmitting a control signal to said gate terminal of said switching device to control the ON-OFF states of said MOS transistors; and means for providing a bias signal to said base terminal of said switching device so that said bipolar transistor will be driven into an ON state by said bias signal when said control signal drives said MOS transistors into an ON state to provide a main current flow between said collector and emitter terminals of said switching device.