Low-component count BJT technology-based currentcontrolled tunable resistors and their applications

In this study, low-power and low-component count grounded and floating current-controlled tunable resistors are proposed. The validity of the proposed resistor circuits is demonstrated in two applications, second-order band-pass filter and negative inductor simulator circuit. To carry out the performance of the circuits, all the designed circuits are simulated through SPICE program by using real transistor models. Also, experimental results are included to confirm the theory. It is important to note that all the introduced circuit parameters and resistor values can be changed electronically by adjusting the values of dc control current sources only. Approximately four decades tunability range (from 34 Ω to 285 kΩ) and about 10 MHz bandwidth for the tunable resistors are achieved. In this tunability range, linear relationships between terminal currents and voltages are successfully obtained.