Pathological element-based active device models and their application to symbolic analysis

This paper proposes new pathological element-based active device models which can be used in analysis tasks of linear(ized) analog circuits. Nullators and norators along with the voltage mirror-current mirror (VM-CM) pair (collectively known as pathological elements) are used to model the behavior of active devices in voltage-, current-, and mixed-mode, also considering parasitic elements. Since analog circuits are transformed to nullor-based equivalent circuits or VM-CM pairs or as a combination of both, standard nodal analysis can be used to formulate the admittance matrix. We present a formulation method in order to build the nodal admittance (NA) matrix of nullor-equivalent circuits, where the order of the matrix is given by the number of nodes minus the number of nullors. Since pathological elements are used to model the behavior of active devices, we introduce a more efficient formulation method in order to compute small-signal characteristics of pathological element-based equivalent circuits, where the order of the NA matrix is given by the number of nodes minus the number of pathological elements. Examples are discussed in order to illustrate the potential of the proposed pathological element-based active device models and the new formulation method in performing symbolic analysis of analog circuits. The improved formulation method is compared with traditional formulation methods, showing that the NA matrix is more compact and the generation of nonzero coefficients is reduced. As a consequence, the proposed formulation method is the most efficient one reported so far, since the CPU time and memory consumption is reduced when recursive determinant-expansion techniques are used to solve the NA matrix.Promep-Mexico UATLX-PTC-088Junta de Andalucía TIC-2532Ministerio de Educación y Ciencia TEC2007-67247, TEC2010-14825UC-MEXUS-CONACyT CN-09-31

Symbolic framework for linear active circuits based on port equivalence using limit variables

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Symbolic analysis of analog circuits containing voltage mirrors

7 páginas, 7 figuras, 2 tablas, 4 imágenes.-- Open Access: This article is distributed under the terms of the Creative Commons Attribution Noncommercial License.The pathological elements voltage mirror (VM) and current mirror (CM) have shown advantages in analog behavioral modeling and circuit synthesis, where many nullor-mirror equivalences have been explored to design and to transform voltage-mode circuits to current-mode ones and viceversa. However, both the VM and CM have not equivalents to perform automatic symbolic circuit analysis. In this manner, we introduce nullor-equivalents for these pathological elements allowing to include parasitics and to perform only symbolic nodal analysis. The nullor-equivalent of the CM is extended to provide multiple-outpus (MO-CM). Finally, two active filters containing VMs, CMs and MO-CMs are analysed to show the usefulness of the models.This work is supported by: UC-MEXUS and CONACyT under grants CN-09-310 and 48396-Y; by Promep-Mexico under grant UATLX-PTC-088; by Consejeria de Innovacion, Ciencia y Empresa, Junta de Andalucia-Spain TIC-2532; and by the JAE-Doc program of CSIC co-funded by FSE, Spain.Peer reviewe

TOPOLOGICALLY MINIMAL REALIZATION OF A NEGATIVE RESISTOR USING NULLORS AND POSITIVE RESISTORS

Although it is heuristically well-known that a negative resistor can be realized with nullors and positive resistors, the minimal realization of it have not been discussed systematically in detail. In this paper, based upon the general fundamental properties of linear active networks, it is proved systematically that nullors not less than one (two) and positive resistors not less than three ( one, respectively ) are necessary to realize a negative resistor and there exist only two circuits for the topologically minimal realization disregarding the labelling of nullors and resistors

Techniques for input ripple current cancellation : classification and implementation

Author name used in this publication: J. C. P. LiuAuthor name used in this publication: C. K. TseAuthor name used in this publication: M. H. Pong2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

A novel design of active inductors based on current controlled voltage sources

This brief presents a new structure of active inductors. These synthetic inductors are designed using current controlled voltage sources. The signal flow graph method is used for this purpose. For the practical realization, operational transresistance amplifiers (OTRAs) are replicated using current conveyors. The proposed inductors have very interesting properties because the value of its inductance is proportional to the product of the parameter of the OTRAs (rm1rm2) and thus, small capacitor values can be used. Current conveyor based simulated inductors are presented and SPICE simulations are given to show the viability of the proposed synthesis technique. ©2010 IEEE

Multiparameter symbolic sensitivity analysis enhanced by nullor model and modified coates flow graph

In symbolic sensitivity analysis very important role plays the number of additionally generated expressions and in consequence additional number of arithmetical operations. The main drawback of some methods based on the adjoint graph or on the two-graph technique, i.e. the necessity to multiply analyze the corresponding graph, is avoided. Advantages of the method suggested are that, the matrix inversion is not required and the Coates graph is significantly simplified. Simplifications of the method introduced in this paper lead to the significant reduction of the final symbolic expressions without violation of accuracy. This simplification method can be considered as SBG-type and has an important impact on symbolic analysis. A special software tool called "HoneySen" has been developed to implement the suggested method. In the paper, it was shown that the presented method is more effective than the transimpedance method taking the number of arithmetical operations and the circuit insight into consideration. Comparison results for the multiparameter sensitivity calculations of the voltage the transfer function for a fourth-order low pass filter and a second-order high-pass filter are presented