A pure nodal-analysis method suitable for analog circuits using nullors

Abstract

A novel technique suitable for computer-aided analysis of analog integrated circuits (ICs) is introduced. This technique uses the features of both nodal-analysis (NA) and symbolic analysis, at nullor level. First, the nullor is used to model the ideal behavior of several analog devices, namely: transistors, opamps, OTAs, and current conveyors. From this modeling approach, it is shown how to transform circuits working in voltage-mode to current-mode and vice-versa. Second, it is demonstrated that using nullors, all non-NA-compatible elements can be transformed into NA-compatible ones, this results in a computationally-improved pure-NA method. Third, the computation of fully-symbolic expressions using MAPLEV, is described. It is demonstrated that a symbolic expression gives more insight in the behavior and performance of the circuit. Finally, several examples demonstrate the suitability and appropriateness of the proposed method to be used in education.