Patent ID: 7449935

Claim:
A circuit comprising: an emitter switching configuration of transistors comprising a cascode connection of a power bipolar transistor and a power MOS transistor; and a driving circuit for the emitter switching configuration which operates to control a saturation level of the emitter switching configuration in applications which provide a highly variable current to the collector of the transistor, comprising: a circuit mesh to transfer a predetermined voltage value, derived from a level translated supply voltage reference, to a control terminal of said power bipolar transistor, the circuit mesh including a controllable active element; and a current/voltage converter coupled to the power MOS transistor to sense collector current of the power bipolar transistor device and supply a control voltage to a control terminal of a first bipolar transistor coupled to the controllable active element of said circuit mesh so as to control variation of said predetermined voltage value in proportion to the collector current of the power bipolar transistor device.