Low power off-chip driver circuit

摘要

Power dissipation in an off-chip driver circuit is decreased by utilizing a selectively switched transistor to discharge the base of the output pull-down transistor, and by using a large resistance in the base current path for the first stage of the Darlington pull-up transistors. An additional transistor having a larger emitter area and coupled to a lower potential source is connected in parallel with the normal phase-splitter transistor to provide additional output current sinking capability, and a current mirror is connected to control the current through both the phase splitting transistor and the additional transistor to control the turn-on transition of the pull-down output transistor.