Synthesis of optimal current copiers for low-power/low-voltage switched-current circuits

Abstract

This paper deals with the noise issue of current copiers. It introduces a structure function for a current copier to estimate its SNR (signal-to-noise ratio). Different copiers have different structure functions. A current copier with a higher structure function value has the larger SNR. This paper also defines the figure-of-merit (FOM), a performance measure, for various current copiers in terms of SNR, power dissipation, settling time, and the storage capacitance. Several current copiers are compared with their FOMs. Based on the desired FOM, this synthesis process provides the designers with the optimum transistor size and storage capacitor for the selected current copier.