controlled resistors

In this paper, a floating voltage controlled positive resistor (FVCPR) with its applications is studied in detail. Compared to previously reported resistor topologies consisting of excessive number of CMOS transistors and dissipating much power, the advantages of the FVCPR are to employ only two CMOS transistors in triode region, and to dissipateal most no power when applied input voltage/current is zero. The FVCPR has two control voltages for electronically changing the value of its positive resistance. Also, one of the control voltages can be used to tune the resistive component while keeping the other one constant. A transadmittance-mode (TM) four-quadrant multiplier, a TM sinusoidal frequency doubler and a TM squarer circuit are derived from the FVCPR as application examples. Some time and frequency domain analyses with SPICE simulation program and an experimental test result are included to exhibit the work ability and effectiveness. (C) 2010 Elsevier GmbH. All rights reserved