OUTPUT DEVICE OF PSEUDO DARLINGTON STRUCTURE

摘要

PURPOSE:To reduce the power consumption of a Darlington-connected circuit by switching operations for a large and a small output. CONSTITUTION:A current is inputted to a terminal IN. A current I3 flowing to the base of a transistor (TR) 1 through a resistance 3 turns of the TR1. When an output current IOUT is small, the collector-emitter voltage of the TR1 is lower than the base-emitter voltage, so a pnp TR5 turns on and an npn TR2 turns off. Therefore, only the TR1 operates. When the output current IOUT becomes great, the npn TR1 enters an active area and the collector-emitter voltage becomes higher than the base-emitter voltage; and the TR5 turns off and the TR2 turns on. Therefore, the power consumption in a small-current area is reduced.