Independently tunable high-input impedance voltage-mode universal biquadratic filter using grounded passive components

Abstract

This paper presents an independently tunable high-input impedance voltage-mode universal biquadratic filter using one plus-type second-generation current conveyor (CCII+), one full differential current conveyor (FDCCII), two grounded capacitors and three grounded resistors which can realize voltage-mode universal filtering responses (lowpass, highpass, bandpass, notch and allpass) from the same topology. The proposed circuit not only permits orthogonal tunability of ω₀ and Q but also achieves independent tunability of ω₀ and ω₀/Q by using only grounded resistors without any matching conditions. Moreover, the proposed circuit still offers the following advantages: (i) high-input impedance, (ii) the employment of all grounded passive components, (iii) the employment of only two current conveyors, (iv) no need of component matching conditions for realizing any filter responses, (v) no need of extra inverting or non-inverting amplifiers for special input signals, and (vi) low active and passive sensitivities. H-spice simulations with TSMC 0.18 μm 1P6M CMOS process technology validate theoretical predictions.