A CCII‐based wide frequency range square waveform generator

SUMMARY In this paper, we propose a novel current-mode solution suitable for the square waveform generation. The designed oscillator, which utilizes only two positive second-generation current conveyors as active blocks, six resistors and a capacitor, is based on a current differentiation, instead of voltage integration, typical of developed solutions both in voltage-mode and in current-mode approaches, so avoiding circuit limitations due to the node saturation effects. The proposed circuit has been designed, as an integrated solution at transistor level, in a standard CMOS technology, with low-voltage (± 1V) and low-power (430µW) characteristics. Simulation results have confirmed the good circuit behaviour, also for working temperature drifts, showing good linearity in a wide oscillation frequency range, which can be independently adjusted through either capacitive (in the range pF − µF) or resistive (in the range M Ω–G Ω) external passive components. Waiting for the chip fabrication, preliminary measurements have been performed using a laboratory breadboard employing the CCII with AD844 commercial component and sample capacitors and resistors. The experimental results have shown good agreement with both simulations and theoretical expectations. Copyright © 2011 John Wiley & Sons, Ltd.