LOW POWER VARIABLE BASE DRIVING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide an output circuit which can supply variable base driving to a pull-down bipolar transistor. SOLUTION: An output circuit (10) has a current restriction branch and a base driving branch. A control transistor (M1) is logically connected to an enable signal and a propagated input signal. A current path to the base of a bipolar pull-down transistor (Q1) connected to output is established by energizing the control transistor. The current restriction branch includes a resistance device and a current restriction transistor which is connected to it in series. The resistance device is connected to the control node of a base current transistor so that a current to the base of the pull-down transistor is reduced when a load to an output node is reduced.