Voltage controlled resistor using quasi-floating-gate MOSFETs

A voltage controlled resistor (VCR) using quasi-floating-gate MOSFETs (QFGMOS) suitable for low voltage applications is presented. The performance of the VCR implemented with QFGMOS is compared with its floating-gate MOSFET (FGMOS) version. It was found that QFGMOS offers better performance than FGMOS in terms of frequency response, offsets and chip area. The VCR using QFGMOS offers high bandwidth and low power dissipation and yields high value of resistance as compared to its FGMOS counterpart. The workability of the presented circuits was tested by PSpice simulations using level 3 parameters of 0.5μm CMOS technology with supply voltage of ± 0.75V. The simulations results were found to be in accordance with the theoretical predictions.