Download The George Washington University School of Engineering and

The George Washington University
School of Engineering and Applied Science
Department of Electrical and Computer Engineering
Circuit Design Verification
Using PSpice (Cadence/OrCAD)
Jason Woytowich (former GTA)
Farid Hassani (ECE GTA)
Outline
• Introduction
• General Process
• Basic Example – Half-Wave Rectifier
• Advanced Example – Demodulation
Introduction
• SPICE is a general purpose circuit simulation
language that performs non-linear DC, transient
and linear steady state AC analysis.
• SPICE models:
– Linear circuit elements of resistance, capacitance,
inductance, independent and dependent current and
voltage sources
– Four of the most common nonlinear semiconductor
devices (Diodes, BJTs, JFETs and MOSFETs)
– Other useful circuit elements including transmission
lines and mutual inductance
Cadence PSpice
• OrCAD bought MicroSim and its PSpice
products in January 1998.
• Cadence bought OrCAD in August 1999.
General Process
1. Design your circuit
2. Draw your circuit
3. Specify your analysis
4. Run the simulation
5. Analyze the output
6. Go back to 1, 2 or 3 as needed
Starting Cadence
Starting Cadence
Start a New Project
Select Project Options
Project Types
•
Only two types are of immediate concern
1. Analog or Mixed A/D
-
The project is meant for simulation. This is for design
verification.
2. Schematic
-
This option is used for PCB design. It is only used to
generate a netlist. We will use this for your Board
Fabrication Details.
Create a Blank Project
Schematic
Place Parts
Placing Parts
Changing Values
Completed Half-Wave Rectifier
Create a Simulation Profile
Set the Simulation Parameters
Simulation Types
• DC / OpPoint – All AC sources are zeroed
(Shorted/Opened)
• Transient – View with respect to time
• DC Sweep – View the response to a range
of DC inputs
• AC Sweep – View the response to a range
of frequencies
Run the Simulation
• Press the blue arrow in the toolbar on the
top.
Select Output
Output 1
More Output
Output 2
A More Complicated Example
• Input – 5Vpeak, 2kHz Sine Wave pulsed for 5ms
ever 20ms starting 1ms and an output impedence
of 1kOhm
• The input passes through a simple BPF with a
gain of 1.
• The output of the BPF is rectified and passed
through an RC filter with a time constant of
0.5ms.
• Put the output across a 1Meg Ohm resistor.
Using Heirarchy
•You can break your Pspice design into
modules.
•These modules can be linked together
at the top level.
Signal Source
MULT – From
ABM
VDC
VSI
N
VPULS
E
Band Pass Filter
LM741 from OPAMP
Input
Port
Output
Port
Notice the power supply
connections
Rectifier
Top Level
Simulation
• Is the output what you expect?
Simulation
Perform Your Own Simulations
This presentation was adapted from a
presentation by Farid Hassani