DIFFENTIAL AMPLIFIER WITH DYNAMIC BIASING

摘要

The differential amplifier current folder circuit of the present invention employs dynamic biasing to provide supplemental bias currents to the collector-emitter paths of the differential amplifier transistors in proportion to the magnitude of the input signal. Since the bias current through the main coding path comprising the coding and weighting network is thus determined only by the magnitude of the input signal and not by the magnitude of a bias current predetermined in accordance with expected peak magnitude input signals, the I DELTA R voltage drop and leakage currents in the folder circuit are proportional to the magnitude of the input signal. Lower magnitude input signals can thus be coded with a minimum of error using either thin film techniques or components readily available from commercial sources.