VOLTAGE_CONTROLLED_HYSTERESIS

Published:2009/6/29 1:52:00 Author:May | From:SeekIC

Pre-cise, independent control of comparator trip point and hysteresis is achieved by switching hysteresis control signal eh to comparator input with Q1 and Q2 when opamp changes state. Circuit avoids hysteresis feedback error while achieving inherent 0.01% trip-point accu racy of comparator. Control voltage et determines first trip point. When opamp output is negative, Q2 is held off and Q1 is on for connecting noninverting input to ground. Output switching oc curs when input signal ei drives input of inverting amplifier to zero.—J. Graeme, Comparator Has Precise, Voltage-Controlled Hysteresis, EDN Magazine, Aug. 20, 1975, p 78 and 80.



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