Design and experiment of VDCC-based voltage mode universal filter

Abstract

In the present paper, configurations of the three new voltage-mode universal biquad filters are presented. The first filter is three-inputs single-output (TISO) filter which can realize all the five standard types of biquadratic functions in voltage-mode that is low-pass, band-pass, high-pass, band-stop and all-pass filter with single VDCC. The second filter has single-input and dual-output, which can also simultaneously realize the high-pass and band-pass filter functions. The third circuit is universal filter with single-input and dual-output, which can simultaneously realize low-pass and band-pass filters. Simulation results are given to confirm the theoretical analysis. The presented biquad filters are simulated using TSMC CMOS 0.18 µm technology. To realize TISO filter with discrete elements VDCC block experimentally generated with operational transconductance amplifier, OPA860. Experimental results of the filter agreed well with the theoretical analysis and SPICE simulations.