Resistor-less switched capacitor biquad filter using current follower transconductance amplifier

The proposed paper employs the idea of replacing a grounded resistor by a switched capacitor resistor in the realization of filter functions using CFTAs. In the given scheme a switched capacitor resistor is employed along with CFTA to realize universal filter. The idea is to avoid grounded/floating resistors in the filter circuit and to replace them by two nMOS transistors and an additional grounded capacitor. This paper aims to show how the switched - capacitor concept can be used to realize a resistor less biquad filter using a single Current Follower Trans-conductance Amplifier (CFTA) that have the advantages of compactness and tunability. The proposed circuit realizes current-mode LP, HP, BP filter functions with a single current source at the input. The BR and AP filters can also be obtained from the proposed circuit. This circuit implies two grounded capacitors, one switched capacitor and one CFTA without any extra active and passive electronic components. É₀ and Q₀ can also be controlled through clock frequency of switched capacitor. The circuit exhibits low active and passive sensitivities for É₀ and Q₀ -Due to the current mode circuit it consumes less power. Simulation results are obtained using PSPICE software which is in conformity with the theoretical findings.