DRIVING CIRCUIT FOR CASCODE TYPE BIMOS

PURPOSE:To make a large-sized transformer unnecessary, and to obtain a driving circuit of high speed and low power by connecting a pre-stage bipolar transistor (TR) to the prestage of a bipolar TR of a cascode type BiMOS and forming a Darlington constitution only at the time of turn-on. CONSTITUTION:When a signal is inputted to a gate of a power MOSFET 12 from a signal source 4, the FET 12 is turned on and a capacitor 3 is discharged, this discharge current becomes a base current of a bipolar transistor 11, and the TR 11 is turned on. Subsequently, a capacitor 23 is discharged, this discharge current becomes a base current of a pre-stage bipolar tanasistor 21, and the transistor 21 is turned on. At a steady time, the base current is supplied through a resistance 24 from a power source 5. When the signal is removed from the gate of the FET 12, the FET 12 is turned off, and first of all, the transistor 11 becomes emitter cut-off, a collector current becomes a reverse current of the transistor 11, and the transistor 11 is turned off. As a result, the transistor 21 also becomes emitter cut-off, and turned off.