Elliptic Biquadratic Sections Using Second Generation Current Conveyors (CCIIs)

In this paper we propose a new, programmable, easy-tunable, current-mode general-purpose Biquad (C-GP-B), using second-generation current conveyors (CCIIs), based on the well-known direct form II, which, among other transfer functions, is also suitable to realize band-rejection (BR) or notch transfer function. It is convenient for elliptic transfer function realizations because it can realize finite transfer function zeroes. Since it has low sensitivity and grounded capacitors it is suitable for integrated circuit (IC) design. The new Biquad is then compared in sensitivity performance with other two CCII-based versions of biquadratic sections obtained by different approaches. Since all presented Biquads use CCIIs they operate in the current mode, and are therefore suitable to realize filter circuits operating at higher frequencies, consuming less power, and needing lower supply voltage. As an example, the design procedure, and the Monte Carlo sensitivity analysis using PSpice were performed for a fourth-order elliptic low-pass (LP) filter.