Electronically tunable current-mode universal biquadratic circuit using current controlled unity gain cells

This paper introduces an electronically tunable current-mode universal biquadratic circuit employing current controlled unity gain cells. The circuit is constructed with two current controlled current followers (CCCFs), two CCCFs with voltage buffers (CCCFBs) and two grounded capacitors. The circuit can realize low-pass (LP), band-pass (BP), high-pass (HP), band-stop (BS) and all-pass (AP) transfer functions by the selection and addition of appropriate current outputs without any component matching conditions. Additionally, the circuit parameters ω0 and Q can be tuned orthogonally through adjusting the bias currents. The biquadratic circuit enjoys very low sensitivities with respect to the circuit components. An example is given together with simulation results by PSPICE.