A Novel Dual-Mode Dual Type Hysteresis Schmitt Trigger and its Applications using Single Differential Voltage Current Conveyor Transconductance Amplifier

Abstract

This paper introduces a novel Schmitt trigger circuit that can operate in two modes: voltage and trans-impedance mode using a sole Differential Voltage Current Conveyor Transconductance Amplifier (DVCCTA) within the same topology with external grounded resistors. The suggested designs enable dual-type hysteresis (clockwise (CW) and counter-clockwise (CCW)) simultaneously within the same circuit topology. Additionally, the proposed design includes the unique ability to control threshold levels through the transconductance parameter (g m ) of DVCCTA via a grounded resistor. The proposed Schmitt trigger is extended for the application of a square/triangular waveform generator and pulse width modulator to illustrate the utility of the given Schmitt trigger circuit. All the proposed designs are appropriate for IC integration due to the available grounded passive attributes. Moreover, the design comes with a feature of independent control of oscillation frequency using a grounded capacitor eliminates the highest level of parasitics, and lessens the circuit's sensitivity to noise immunity. The maximum absolute deviation of output amplitude is observed to be less than 0.062 % (for CW mode) and 0.038 % (for CCW mode), while for threshold voltages, it is below 0.528 % (CW) and 0.321 % (CCW), respectively against for temperature variations of 0-100 0 C. Realization of DVCCTA uses 20 MOS transistors with 0.18 µm TSMC CMOS technology parameter, which is used to authenticate the workableness of the proposed design through PSPICE. Additionally, Monte Carlo simulations, temperature-dependent variations, non-ideal analysis, schematic layout with post-layout simulation, and also experimental results using ICAD844 are presented to validate the proposed design. The simulated responses correlate with the theoretical prediction.