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

 

E. Tlelo-Cuautle, L.A. Sarmiento-Reyes

 

INAOE Electronics Departament, Puebla, Mexico. etlelo@inaoep.mx

 

Received: September 28^th 2001.
Accepted: January 23^th 2003.

 

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.

Keywords: CAD Tools, Circuit Theory, Nullors, Analog Modeling, Symbolic Analysis, Nodal Analysis.

 

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Acknowledgement

The authors would like to thank to INAOE for funding. This work has been supported by CONACYT / Mexico under the project J4032.

 

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