Tunable versatile current-mode universal filter based on plus-type DVCCs

This paper presents a new tunable versatile current-mode universal filter with four inputs and three outputs. The proposed configuration employs three plus-type differential voltage current conveyors, two grounded capacitors and three grounded resistors. Its high impedance outputs enable easy cascading in current-mode operation. The circuit can be used as either a single-input and three-output or four-input and two-output. In the operation of single-input and three-output circuit, the bandpass, highpass and bandreject filtering responses can be realized simultaneously. In the operation of four-input and two-output circuit, both inverting and non-inverting type lowpass, bandpass, highpass, bandreject and allpass filtering responses can be simultaneously realized by selecting different four input current signals. The filter permits orthogonal controllability of the quality factor and resonance angular frequency by adjusting the grounded passive components. No component matching condition is required for realizing all the filter responses, and all the passive and active sensitivities are low. HSPICE simulation results based on using TSMC 0.18 μm 1P6M CMOS process technology and supply voltages ±0.9 V to verify the theoretical analysis.