The Art of Simulation Using PSPICEAnalog and Digital

Bashir Al-Hashimi

• Publisher: CRC Press
• Year: 2019
• eBook ISBN: 9781000722611
• Topic: Technology & Engineering
• Subtopic: Computer Science General
• Index: Technology & Engineering

This comprehensive volume covers both elementary and advanced analog and digital circuit simulation using PSpice. The text includes many worked examples, circuit diagrams, tables, and code listings. It also compares practical results with those obtained from simulation.

Chapter One

 

Introduction

1.1  Brief history of SPICE

SPICE stands for “Simulation Program with Integrated Circuit Emphasis”. It is a powerful computer package used to analyse electronic circuits. SPICE was developed in the early 1970s in the Department of Electrical Engineering of the University of California at Berkeley, progressing through various versions, culminating in 1981 with SPICE 2G.6, which is the version on which most commercial circuit-simulation packages are based. The algorithms used in SPICE are discussed in detail in Reference 1. It should be noted that the program SPICE is freely available. Although SPICE 2G.6 is a powerful and robust program, it did not gain popularity in nonacademic circles for a number of reasons. The early versions needed to run on mainframe computers and had “user-unfriendly” interfaces. It was not interactive and lacked the ability to simulate digital and mixed analogue /digital circuits. Finally, there were no component libraries, and all these features made the original SPICE unattractive.

A number of commercial organisations could see the potential of the core software, provided that these shortcomings were rectified, and versions are now available for use on a variety of computers ranging from PCs to mainframes. Table 1.1 shows some IBM-PC-based SPICE versions. Reference 2 gives a detailed list of commercially available circuit-simulation packages, including workstations and mainframe computers.

PSpice is arguably the industry standard for circuit-simulation packages with more than 17,000 copies sold worldwide to date.

1.2  Book structure

This book is based on PSpice Design Center, Version 5.3, and consists of nine chapters. The first six chapters cover all aspects of PSpice circuit simulation and analysis. Chapters 7 to 9 cover the advanced simulation features.

Table 1.1  Some Commercially Available PC-Based SPICEs

PSpice contains more than 20 command instructions that allow the designer to perform various circuit simulations. The book is organised in a way that is parallel to the normal development and testing of an electronic circuit. Chapter 2 deals with the description of passive components and simple active elements (diodes and transistors), and it shows how to generate the circuit in a form that PSpice understands (the “netlist”). Other key parameters, such as DC and AC sources and power supplies, are also introduced. The reader should be able to produce simulation results of simple circuits by the end of the chapter.

Chapter 3 builds on Chapter 2 and introduces the important concepts of time-domain and Fourier analysis, which are often used in measuring the performance of circuits (such as transient response). The complex active devices are dealt with in Chapter 4, where amplifiers and similar devices are described in terms of controlled sources and equivalent circuits. Having completed Chapter 4, the reader should be able to perform extensive simulations.

Complex circuits often contain repetitive circuit elements, and these may be expressed as subcircuits. Chapter 5 covers the definition and use of the subcircuit approach in circuit description. Actual op-amp models (macromodels) and their usage are discussed in Chapter 6, which also compares and contrasts the result from various simulations with the practical results. Chapters 7 to 9 discuss in detail various specific simulation topics (including sensitivity and Monte Carlo analyses, analogue behavioural modelling and mixed analogue/digital simulation).

The seven appendices that accompany this book provide the user with additional information on the advanced usage of PSpice and specific circuit-simulation problems. Appendix A lists some of the common error messages reported by PSpice when there is an error in the circuit. Appendix B shows how time-dependent input signals are generated using the program (StmEd). Appendix C covers the simulation of oscillator circuits, and Appendix D deals with the simulation of switched capacitor networks. The simulation of ideal and lossy transmission lines is discussed in Appendix E, and Appendix F explains the various PSpice control options. Finally, Appendix G covers the simulation of CMOS circuits.

1.3  PSpice syntax

PSpice syntax is simple because it has only two kinds of statements, description and control. Description statements tell PSpice about component types and their connections, while control statements instruct PSpice to perform particular tasks or analyses. These control statements are differentiated from the description statements by always beginning with “.”.

1.4  Simulation hierarchy

The use of circuit-simulation packages is increasing because of the advantages they offer the user. At the simplest level they allow designers to verify whether their circuits function as designed. This level of simulation often represents stage one of the simulation process. Ideal component models are often assumed during this stage of simulation. The objective of the stage one simulation is to make certain that the designer has not made any fundamental mistakes in the design. The advantage of stage one is that it takes little time and effort to produce simulation results, while the disadvantage is that only ideal circuit performance is predicted. Chapters 2 through 5 deal with stage one of circuit simulations.

To improve the accuracy between the simulation and the practical results, more complex component models are needed in the simulation. Here, the user has to decide on the accuracy required in the simulation. Generally, the higher the accuracy required, the more time, effort, and better understanding of the circuit operation are required. The simulation process might also involve examining the sensitivity of the circuit to component and temperature variations. This type of simulation often represents stage two of the simulation process, which is dealt with in Chapters 6 and 7.

So far, component-level simulations have been considered. PSpice offers the designer the option to perform system-level simulation, which can be a very effective method of simulating complex circuits. This is accomplished by the use of analogue behavioural modelling and is discussed in Chapter 8. The majority of today’s electronic circuits contain both analogue and digital circuitry. PSpice allows the designer to simulate the performance of such systems, and this is covered in Chapter 9.

Figure 1.1  Book structure.

1.5  Chapter summary

The book has been organised as to emphasise the hierarchical viewpoint of component and system simulation, as illustrated in Figure 1.1. Much simulation can be carried out with a working knowledge of Chapters 2 through 4. However, later chapters build on these to enable a more complex system-level approach to be realised by the reader.

References

1. 1. Nagel, L.W., SPICE2: A Computer Program to Simulate Semiconductor Circuits, ERL Memo No. ERL-M520, Electronics Research Laboratory, University of California, Berkeley, May 1975.
2. 2. Swager, A.W., “Behavioral Models Expedite Simulation”, EDN Magazine, November 1991. pp. 67-75.

Chapter Two

Circuit entr...

Table of contents

• Cover
• Series Page
• Half Title
• Title Page
• Copyright Page
• Preface
• Contents
• Dedication
• 1 Introduction
• 2 Circuit Entry and Preliminary Analyses
• 3 Transient and Fourier Analyses
• 4 Dependent Sources (Linear And Nonlinear)
• 5 Subcircuits and Efficient Use of PSpice
• 6 Analogue Device Models and Libraries
• 7 Sensitivity and Monte Carlo Analyses
• 8 Analogue Behavioural Modelling “Block-Diagram” Simulation Approach
• 9 Digital and Mixed Analogue/Digital Simulations
• Appendix A PSpice Error Messages
• Appendix B Stimulus Editor (StmEd)
• Appendix C Simulation of Oscillator Circuits
• Appendix D Simulation of Switched Capacitor Networks
• Appendix E Simulation of Transmission Lines
• Appendix F PSpice Control Options
• Appendix G CMOS Circuits Simulation
• Index