A Current-Mode Nth-Order Multifunction Filter Using Minimum Number of DVCCs

In this paper, a nth-order current-mode universal filter based on differential voltage current conveyors (DVCCs) is proposed. Using minimum number of passive Components, The filter obtained from the proposed structure can simultaneously realize low-pass, band-pass, all-pass, high-pass and band-reject responses by choosing appropriate input branches without changing the passive elements. The obtained nth-order filter is only composed by n DVCCs and n capacitors and n resistors. All capacitors and resistors are grounded, which is integrated conveniently and is compatible with VLSI technology. The proposed filter requires no active and passive element matching conditions and/or cancellation constraints. Additionally, a universal biquadratic filter as an example is introduced. The second-order filter has low active and passive element sensitivities, and offers orthogonal control of the angular resonance frequency (?o) and quality factor (Q). HSPICE simulations are performed employing 0.18μm CMOS process and the performance simulation results are tested by comparing with the theoretical results of the filter.