The modified nodal approach to network analysis

The use of pathological elements (i.e., nullators, norators, and the voltage mirror-current mirror pair) as universal active elements opens up the possibility to model the behavior of active devices with either differential features or input-output multiples, in order to be used in analysis tasks of linear(ized) analog circuits. This brief tries on the modeling this class of active devices, which is carried out by considering the impedance characteristics along with the behavior equation of each active device, the kind of signal to be processed and by applying the pathological element properties. In order to obtain a more realistic model, not only parasitic elements associated to the input-output terminals of each active device are considered, but the tracking errors of voltage and current differential followers modeled with grounded pathological elements and admittances are also included. Due to that the gain and tracking errors are finites and of limited bandwidth, a two-pole model is used for each of them in order to include their contributions on the symbolic expressions computed. Because the behavior of fully-differential amplifiers is modeled with grounded pathological elements, a standard nodal analysis can be performed. This imply that not only the size of the admittance matrix is smaller than those generated by applying modified nodal analysis (MNA) method, for instance, but also the number of nonzero elements and the generation of cancellation-terms are both reduced. As a result, the computational complexity during the solution of the system of equations is reduced when recursive determinant-expansion techniques are applied. Examples are described and compared with the MNA method, in order to show the usefulness of the proposed models to compute fully-symbolic small-signal characteristics of analog circuits containing fully-differential active devices and/or with input-output multiples.

Adding mushroom-like electromagnetic band-gap (EBG) structures to split power planes can produce wideband suppression of ground bounce noise in high-speed printed circuit boards. Practical equations are used to estimate the stop-band performance of EBG structures within parallel power planes. In this article, a mushroom-like EBG and power-bus structure are derived using the modified nodal analysis (MNA) method. Equations calculated using the MNA method are easily programmable. The partial EBG structures developed in this article can suppress noise from electromagnetic (EM) interference within parallel plates in the power bus. Several examples below show that similar results can be obtained in measurements, in EM simulations software, and in derived equations. The proposed structure enhanced the suppression of simultaneous switching noise coupling (≤-40 dB) within the range of 260 MHz to 10 GHz.

Deep water oil and gas resources play an important part in the energy mix of today's world, and ultra deep water oil and gas production has been the frontier of the oil and gas industry for the past decades. As the technological advancements push the limits of the industry's capability in the realm of ultra deep water exploration and production, more and more complexities are involved in the technical developments of these fields. Some deep water fields are identified as candidates for enhance oil recovery (EOR) methods. Very recently, several major deep water projects around the globe are including a miscible gas flood in their field development plan. Miscible EOR, combined with extreme conditions such as high temperature, high pressure, ultra deep water and reservoir depths, poses brand new challenges in production engineering designs. This paper gives a summary of multiple challenges in the production lift performance for green field development of a gas miscible flood in deep water field. The authors have identified several key aspects in the nodal analysis methods that can potentially make significant impact on the accuracy of the predicted production lift performance for such fields. They include, among others, the characterization of fluid PVT (Pressure Volume and Temperature) and its implementation in nodal analysis tools, the use of fit-for-purpose vertical lift correlations, the implementation of compression constraints for gas injection, and the use of subsea pipeline rate multiplier as an approximation for subsea layout. Methodologies of resolving these challenges are proposed, and their limitations are discussed. This paper sheds light on improving the accuracy of nodal analysis of both injection and production for gas miscible EOR fields in deep water.

This paper presents an optimization circuit model of multiconductor transmission lines in the time domain. Several methods allow calculation of the currents and the tensions distributed on the uniform transmission line. Most of these methods are limited to lines with constant losses, and only for linear loads. The macro-model we propose, using Pade approximant, employs more variables and allows it to reduce the necessary cells' number in modelization than the traditional cells cascade method. This macro-model, using the Modified Nodal Analysis method (MNA), is suitable for an inclusion in circuit simulator, such as Esacap, Spice, and Saber. The MNA method offers an efficient means to discretize transmission lines on real and complex cells compared to the conventional lumped discretization. In addition, the model can directly handle frequency-dependent line parameters in the time domain. An example, with experimental measures taken from literature, is presented to validate the model we propose, and show its importance. It is necessary for assuring the results validity obtained from Pade macro-model to study its stability and passivity.

A description is given of a simple but effective modification to a well-known circuit formulation method, modified nodal analysis (MNA), to reduce the number of equations while formulating the circuit equations. For this purpose, a set of simple rules are presented. This new method is compared with the original MNA for simplicity and memory space. The new method is found to be superior to MNA in memory requirement and run time. The complete method of implementing the rules with examples of its use is presented. >

In this paper, the application of the latency insertion method (LIM) to the analysis of charged device model (CDM) electrostatic discharge (ESD) events in integrated circuits (ICs) is discussed. LIM is proposed as an alternative to existing techniques commonly used for chip-level circuit simulation of CDM ESD. Such simulators, based on the modified nodal analysis (MNA) method, can underperform in cases that require very large model sizes. LIM was developed specifically for the analysis of fast transient phenomena in very large networks and is more robust and less resource-hungry than conventional methods.

The method for modeling switching converters plays a key role in real-time simulators. Associate discrete circuit (ADC) modeling technique is a commonly used method for modeling the switching converter. However, the optimal selection of the ADC-based switch model parameters has great importance in the accuracy of the real-time simulator. In this paper, the design of a real-time simulator for a switching power converter has been done, in which a novel method for detecting optimum values of the switch model parameters has been expressed. Particle swarm optimization (PSO) algorithm is used to find these optimum values using state-space analysis of the modeled circuit in the z-domain. The modified nodal analysis (MNA) method solves the real-time model at each simulation time-step. Case studies are a single-phase 5-level Cascaded H-Bridge (CHB), three-phase 9-level CHB inverter, and a Transmission line. Field-programmable gate array (FPGA) has been used as a platform for implementing the real-time simulator. Experimental result of the real-time simulator of the 5-level CHB inverter on a SPARTAN-6 FPGA and its comparison with the result of a prototype of a 5-level CHB inverter confirms not only the performance of the real-time simulator, but also the effectiveness of the proposed method for confirming the real-time simulator accuracy.

The paper deals with a new method for a sensitivity analysis in linear hybrid circuits. The circuits in view can contain elements with both lumped and distributed parameters when multiconductor transmission lines (MTL) play the role of their distributed parts. The technique is based on the modified nodal analysis (MNA) method serving to the basic description of the circuit. Firstly the frequency-domain sensitivities formulae are derived then the numerical inversion of Laplace transforms (NILT) is applied to obtain the time-domain sensitivities. In this paper a novel method for evaluation of sensitivities with respect to distributed parameters is elaborated while considering lossy nonuniform multiconductor transmission lines.

Radiation effects on a ceramic layer

The processes applied on the pixels by the image processing methods provide us information about images. Image processing is a computer programming area which can be used in computer integrated industrial applications and it is one of the research areas of reverse engineering. In this study, a new system in which color digital images are interpreted by using image processing method was developed. The purpose of this study is to improve a system to interpret the images, which are taken with a hand camcorder or digital camera, and to obtain point clouds by evaluating with image processing and to convert these point clouds surface or solid model in a computer aided design program. In accordance with these purposes, the three dimensional point clouds are obtained from a rectangular prism shaped object in the specified area. These point clouds can easily be converted into three dimensional solid or surface models in a Computer Aided Design (CAD) program. In this reverse engineering study, the developed system is explained and sample parts are given.

In this study, the analysis of fixed capacitor thyristor controlled reactor (FC-TCR), one of Static VAR compensation techniques, is performed by modified nodal analysis (MNA). In the analysis, semiconductor elements are modelled with two- valued resistor concept. The resulting equations are solved by Trapezoidal method, used in numerical analysis. All of the simulation results are obtained in Matlab M-File environment.

This paper presents a hybrid approach to the investigation of the performance of printed circuit boards (PCB) by examining the impact of parasitic parameters of the board design on the efficiency of a device. First, parasitic parameters are extracted from the board layout by 3D quasistatic field solvers. Second, the corresponding equivalent circuit is constructed. Third, the extracted parasitic circuits are incorporated into functional circuit model. Finally, Modified Nodal Analysis (MNA) is used to examine a complete network. The hybridization makes it possible to vary circuit parameters and layout independently to achieve maximum system performance. Validation of the proposed method is performed by comparison of simulation results with measurements of GSM band signal amplifier.

This paper presents a hybrid approach to the frequency and time domain simulation of complex cable systems with arbitrary linear or linearized circuits at terminations. Depending on the type of cables to be investigated, either FDTD/MNA or MTL/MNA approach can be recommended. In FDTD/MNA scheme 1D-FDTD method is applied to solve the transient response of a cable system, which is then used together with circuits of termination devices to simulate the complete network by modified nodal analysis (MNA). In the second scheme, MTL theory is used to extract equivalent circuit models of cables. All extracted equivalent circuits are then merged with termination devices and solved using specialized MNA-based circuit solver. Both methods are speed-oriented, provide accurate results and can be used for fast simulation of large-scale cable systems. Validation of the proposed methods is performed by comparison with measurements of high voltage shielded cable test setup. Two application examples demonstrate the potential of the proposed approaches for simulation of large-scale cable systems - automotive harness and office wiring network.

Modified nodal analysis (MNA) can be considered as the most adopted method in circuit simulation programs. Once node equations were written and complemented with those from the current controlled branches, a nonlinear system of algebraic and/or differential equations is obtained. In general, by using linear multistep integration methods, differential equations are recast as nonlinear algebraic ones, which are solved through the Newton method at each integration time step. While computer precision is not an issue in most situations, some specific but frequent cases yield ill-conditioned or singular matrices even in originally well posed circuits. This drawback can occur in different situations namely in presence of strongly nonlinear elements and/or when very small integration time steps are used. In the second case, very large conductances in the companion model of capacitors can introduce roundoff errors. In this paper, a transformation of the MNA that overcomes these problems is proposed. It is based on a suitable recombination of equations and electrical variables of the conventional MNA and it can be easily implemented in a circuit simulator.

This paper presents a simulation technique and a computer program for fast DC analysis of MOS transistor based VLSI circuits. Time domain analysis of a VLSI circuit is evaluated by a piecewise constant waveform approximation. This approximation is realized by repeatedly applying the developed DC analysis engine with initial conditions. All proposed methods such as device modeling, circuit partitioning and event-driven simulation were implemented and combined with such well known algorithms as modified nodal analysis (MNA), Katzenelson algorithm and Gaussian elimination in the form of a circuit simulation program: SAMOC. Time domain waveforms and benchmark circuit simulation results comparison of SPICE and SAMOC are presented.