Fitzpatrick Analog Design and Simulation using OrCAD Capture and PSpice

1. Auflage 2011
ISBN: 978-0-08-097096-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 344 Seiten

Analog Design and Simulation using OrCAD Capture and PSpice provides step-by-step instructions on how to use the Cadence/OrCAD family of Electronic Design Automation software for analog design and simulation. Organized into 22 chapters, each with exercises at the end, it explains how to start Capture and set up the project type and libraries for PSpice simulation. It also covers the use of AC analysis to calculate the frequency and phase response of a circuit and DC analysis to calculate the circuits bias point over a range of values. The book describes a parametric sweep, which involves sweeping a parameter through a range of values, along with the use of Stimulus Editor to define transient analog and digital sources. It also examines the failure of simulations due to circuit errors and missing or incorrect parameters, and discusses the use of Monte Carlo analysis to estimate the response of a circuit when device model parameters are randomly varied between specified tolerance limits according to a specified statistical distribution. Other chapters focus on the use of worst-case analysis to identify the most critical components that will affect circuit performance, how to add and create PSpice models, and how the frequency-related signal and dispersion losses of transmission lines affect the signal integrity of high-speed signals via the transmission lines. Practitioners, researchers, and those interested in using the Cadence/OrCAD professional simulation software to design and analyze electronic circuits will find the information, methods, compounds, and experiments described in this book extremely useful. - Provides both a comprehensive user guide, and a detailed overview of simulation - Each chapter has worked and ready to try sample designs and provides a wide range of to-do exercises - Core skills are developed using a running case study circuit - Covers Capture and PSpice together for the first time

Dr Fitzpatrick is a Chartered engineer and lecturer at the University of East Anglia teaching electrical and electronic engineering with a research interest in Biomedical Engineering. His primary research interest is in the use of Functional Electrical Simulation (FES) for the restoration of bladder function and restoration of gait in stroke and spinal cord injured patients. His research focuses on the design and development of custom designed implantable electrodes. His recent book, Analogue Design and Simulation using OrCAD Capture and PSpice, published by Elsevier, has sold worldwide to highly acclaimed reviews in numerous prestigious electronic engineering journals including EDN and Electronic Times, the book being officially endorsed by Cadence Design Systems. Dr Fitzpatrick has published other books in the field of Biomedical Engineering and is the Series editor for the Developments in Biomedical Engineering and Bioelectronics book series by Elsevier.

Autoren/Hrsg.

Fitzpatrick, Dennis

Leseproben

Chapter 1. Getting Started

Chapter Outline

1.1. Starting Capture1

1.2. Creating a PSpice Project2

1.3. Symbols and Parts7

1.3.1. Symbols7

1.3.2. Parts8

1.4. Design Templates10

1.5. Summary12

1.6. Exercises13

Exercise 113

Exercise 215

1.7. Extra Library Work17

Those of you who are familiar with setting up projects and drawing schematics in Capture may want to skip this chapter, as it has been written for those of you who have little or no experience of using Capture. This chapter will describe how to start Capture and how to set up the project type and libraries for PSpice simulation.

At the end of each chapter there are some exercises to do and as you go through the book, each chapter will build upon the exercises from previous chapters.

1.1. Starting Capture

Circuit diagrams for PSpice simulation are drawn in either Capture or Capture CIS schematic editor. The CIS option, which stands for Component Information System, allows you to select and place components from a component database instead of selecting and placing components from a library. For this book, it does not matter whether the circuits are drawn in Capture or Capture CIS.

If you have the OrCAD software installed, launch Capture or Capture CIS, by clicking on:

Start > Program Files > OrCAD xx.x > Capture

or

Start > Program Files > OrCAD xx.x > Capture CIS

where xx.x is the version number, e.g. 10.5, 11.0, 15.5, 15.7, 16.0, 16.2, 16.3 or 16.5.

At the time of writing this book, the current version is 16.5 and is started by:

Start > Program Files > Cadence > Release 16.5

If you have the Cadence software installed, the tools are installed under the Allegro platform name. In this case, only Capture CIS is available and is branded as Design Entry CIS:

Start > Program Files > Allegro SPB xx.x > Design Entry CIS

1.2. Creating a PSpice Project

New designs started in Capture will automatically create a project file (.opj) which will reference associated project files such as the schematics, libraries and output report files.

Before the circuit diagram is drawn, the project type and libraries required for the project need to be set up. First of all a new project is created by selecting from the top toolbar:

File > New > Project

In the New Project window (Figure 1.1), you enter the name of the project and then you have a choice of one of four project types:

FIGURE 1.1 Creating a new project.

• Analog or Mixed A/D is used for PSpice simulations.

• PC Board Wizard is used for schematic to PCB projects.

• Programmable Logic Wizard is used for CPLD and FPGA designs.

• Schematic is used for schematic and wiring diagrams.

When you select a Project type, the Tip for New Users gives a brief explanation of the project type. For PSpice projects, select Analog or Mixed A/D. This will activate the PSpice menu on the top toolbar in Capture.

It is recommended that a new directory location (folder) is created for each new project. This can be done by clicking on the Browse… button shown in Figure 1.1, which opens up the Select Directory window shown in Figure 1.2.

FIGURE 1.2 Creating a project folder location.

By selecting the Create Dir… button, the Create Directory window (Figure 1.3) appears, which allows you to name the directory (folder).

FIGURE 1.3 Creating the project folder.

The created folder, PSpice Exercises in this example, will appear in the Select Directory window. However, you must highlight and select the folder by clicking twice with the left mouse button, which will show the ’open’ yellow icon as shown in Figure 1.4. A further subdirectory or folder can be created by clicking on the Create Dir… in the Select Directory window button and following the same procedure above.

FIGURE 1.4 The project folder has been selected.

The project folder location will then appear in the Location box of the New Project window (see Figure 1.1).

An alternative method of creating the project folder is to type in the folder location directly into the Location box in the New Project window in Figure 1.1 and Capture will automatically create the folder.

NOTE

It is a common mistake to create a project folder and not select the folder. Make sure you double click on the created folder name in the Select Directory window (Figure 1.4).

The next window to appear is the Create PSpice Project window, which sets up the project for PSpice simulation (Figure 1.5).

FIGURE 1.5 Create PSpice Project.

The pull-down menu option allows you to select preconfigured Capture-PSpice libraries for the project. The most commonly used option for new projects is Simple.opj, which adds the following five default libraries to the project:

Analog.olb

Breakout.olb

Source.olb

Sourcstm.olb

Special.olb

These libraries contain the most commonly used parts for PSpice projects and are recommended for new projects.

There is also an option to create updated versions of an existing project, i.e. to create a newer version 2 based upon the original version 1 project. In the Create PSpice Project Window (Figure 1.5), select the function Create based upon an existing project and then Browse to select an existing project. This will copy the existing project and all its associated files into the new project. This is similar to using the File > Save As function.

If the Create a blank project option is selected, then no Capture-PSpice libraries are added to the project. The libraries can be added later. This will be demonstrated in one of the exercises at the end of this chapter.

When a new project is created, a Project Manager window is created (Figure 1.6) which shows the absolute path to the libraries. Remember that these are Capture symbol libraries which define the graphics for the parts. They are not the PSpice model libraries. The Capture libraries are installed by default and can be found, depending on the OrCAD or Cadence software version you are using, for example, at:

FIGURE 1.6 Project Manager showing the Capture parts libraries and their location.

or

Normally the is the C: drive.

TIP

If the Project Manager window is not displayed, select from the top toolbar, Window > file (Figure 1.7). Here the project name is resistors. Note the project name file extension .opj.

FIGURE 1.7 Displaying the Project manager window.

Alternatively, click on the Project manager icon or .

1.3. Symbols and Parts

1.3.1. Symbols

Before drawing a schematic diagram, it is useful to know the difference between a part and a symbol. Symbols differ from parts in that they are not placed from the Place Part menu in Capture. You have to select the symbol from the Place menu (Figure 1.8).

FIGURE 1.8 Place menu.

The Place menu also shows the corresponding shortcut keys. For example, to place a Power symbol, press F and the Place Power menu appears as shown in Figure 1.9.

FIGURE 1.9 Place Power menu.

Wires connected to symbols take on the name of the symbol. For example, to define a wire to be...