ADAPTIVE SCHMITT TRIGGER BASED ON OTA DRIVEN BY DIFFERENTIAL INPUT VOLTAGE FOR SETTING QUIESCENT HYSTERESIS AND COMPENSATING AMPLIFIER OFFSET

Schmitt Trigger, first presented by Schmitt in 1938 is extensively used in Pulse Width Modulation Circuits, Sensors, Square Wave Generators, buffers and Sub threshold SRAM. It utilizes the fundamental concept of bi-stable  state i.e.  for positive and negative going input signals, Schmitt Trigger shows different switching thresholds which is termed as Hysteresis. Slew rate and bandwidth of the op-amp restricts the performance of Schmitt Trigger based on op-amp. Schmitt Trigger using Current Conveyors lack electronically tuned hysteresis level.  CDTA and CCCDTA based Schmitt Trigger are comparatively less efficient owning to excessive use of passive elements, devoid of dual hysteresis operations using same topologies, absence of electronic controllability of output levels and threshold. Keeping all in knowledge,the purpose of this paper is to introduce adaptive or Super Schmitt trigger based on Operational Trans-conductance amplifier with many adjustable parameters to tame input values. In this Differential input voltage to current converter is utilized to drive OTA’s bias.To set the quiescent hysteresis and to compensate the amplifier offset,OTA and Trimmer plays a pivotal role.Using P-spice  Software,results of experimental measurements and simulation are presented that authenticates the theoretical assumptions.