Versatile architecture for current-mode biquadratic filters in CMOS technology

A versatile programmable current-mode architecture for realising a given second order biquadratic filter is proposed. The architecture consists of programmed interconnections of three basic building blocks: transconductance cells, buffered current mirrors and current buffer cells. In the case of stand-alone IC chips, transfer function coefficients are set through external control voltages, and in the case of an analogue/digital mixed mode VLSI environment, through internal control voltages. Designs for a video-band lowpass notch filter and a high-frequency bandpass filter realisable using 1.2 micron CMOS technology and consuming, respectively, 1.96 mW and 2.36 mW of power, are presented as illustrations. It is expected that optimised designs will lead to reduced power consumption