Design of a floating node voltage-controlled linear variable resistor circuit

The floating node voltage-controlled linear variable resistor circuit is a versatile building block in several analog signal processes such as telecommunications and electronics. Floating node voltage-controlled linear variable resistor circuits have been developed by using MOSFET components. In this paper, a floating node voltage-controlled linear variable resistor circuit is proposed. The advantage of the proposed circuit is that it is both linear and compact. The utility of the proposed circuit was confirmed by PSpice simulations. A tunable cut off frequency of an RC filter has been applied with the proposed circuit as an analog building block and the results are presented here. This proposed floating node voltage-controlled linear variable resistor circuit has high linearity and a wide controlling voltage that does not depend on the supply voltage. Evaluation of the floating node variable resistor showed that when the supply voltage was 5 volts, and the bias voltage was from 0 to 1.5 volts, the value stayed in a variable range of from 58 kΩ to 1600 kΩ and the power consumption was 132.5 μW, and -3 dB bandwidth 25 kHz. The simulation results are reported in this paper.