How to use PSPICE
ECE 220: PSpice DC Sweep with a Nested Parameter Sweep
Before you start you should have the schematic below using the
parts indicated in the table below
Creating a Variable
1) Double click on the 2.5K value of the resistor and change it
to the equation {res*1K} (curly brackets are needed) – res is a
variable.2) Hit bindkey p and add the part param from the library
special. This part is used to define variables
3) Click on to close the window and place the part
Q1
Q2N2222
R1
{res*1K}
V1
AC =
TRAN =
DC =
V2
AC =
TRAN =
DC = 5V
Vin
0
Vcc
0
Vcc
0
Vo
PARAMETERS:
Q1
Q2N2222
R1
{res*1K}
V1
AC =
TRAN =
DC =
V2
AC =
TRAN =
DC = 5V
Vin
0
Vcc
0
Vcc
0
Vo
PARAMETERS:
4) On the schematic double click on the word PARAMETERS. You
will see the window below.
5) Click on New Column (or New Row or New Property) - It is
different for different versions6) If prompted answer yes7) In the
Add New Column window type the variable name and give it a default
value (as shown below)
8) Click OK to close the Add New Column window
9) Close the Property Editor Window (top right)
Now you are ready to simulate
Placing Probes
To automatically plot results when a simulation is complete
place voltage probes to plot voltages or current probes for
currents.
10) Place a voltage probe at the output of the amplifier as
shown below and a current probe to plot the collector current. Note
current probes must be placed on the pins of devices (the very edge
– look for the red/blue transition)
Running a DC sweep with a Nested Parametric sweep
11) To simulate from the top toolbar select Pspice->New
Simulation Profile12) Enter a name
13) Click on create to close the window
14) In the Simulation Settings menu (shown below) tab to
analysis (it should be the default)
15) select DC sweep analysis16) Specify that you wish to sweep a
voltage source
17) Specify the voltage source that you wish to sweep (V1) –
this one is connected to the input of the amplifier18) Specify the
Start and stop voltages as well as the voltage increment
19) Note: Spice understands m to be 10-3
20) Select Parametric Sweep (you will see the window on the next
page)21) Select Global Parameter22) Specify the parameter you wish
to sweep (res)
23) Specify the range for res (start: 1, stop: 5, Increment
2)24) Click on to close the window
25) To simulate click on the run Pspice icon at the top of the
schematic
The simulation will run
Note if your simulation fails check for errors: from top
toolbar: Window->Session Log26) Click on to plot all three
parametric sweeps27) If your simulation runs successfully the
voltages will be plotted as shown below (the current is so small in
comparison to the voltage it will appear to be zero) (see
below)
(the background has been changed to white:
Tools->Options->Color Settings)
Deleting Traces
28) Click on the V(Vo) icon (the text) at the bottom left of the
simulation window (as shown below)
29) click to delete it
30) Also delete the current trace
Adding Traces and Plotting expressions
We will add back the traces for V(Vo) to show another way of
plotting traces
31) In the top toolbar of the Allegro Simulation Simulator
window select: Trace->Add Trace
You will see the Add Traces pop-up menu shown below. On the left
circuit voltages and currents are listed, on the right available
functions
32) Select V(Vo) (you could also form an expression)
33) Select to close the window and plot the expressions
Using Cursors
Cursors can be used to determine precise simulation values.
34) To activate the cursors click on the toggle cursor on icon
at the top of the Simulation window
35) At the bottom of the window you may have to resize the
cursor window to display data
There are two cursors Y1 and Y2. Y1 is controlled with the left
mouse and Y2 with the right.
36) Affiliate cursor Y1 with the left trace of V(Vo)by clicking
on its trace icon (small shape – blue square) with the LEFT mouse
button (see below)
37) Affiliate cursor A2 with the left trace of V(Vo) by clicking
on its trace icon (small shape – blue square) with the RIGHT mouse
button (see below)
38) Click on the actual V(Vo) trace with the RIGHT mouse button
to define the position of the Y2 cursor. Crosshairs will be shown.
X and Y values for this trace at the position of the cross hairs
are displayed in the small Cursor window previously uncovered. The
crosshairs can be moved by dragging the mouse with the right
button.
Note:
· The position of the Y1 cursor is similarly controlled with the
left mouse button
· The difference between the Y1 and Y2 cursors is shown in the
Probe Cursor menu as well.
· Cursors Y1 and Y2 can be used for the same trace or different
ones
· Cursors Y1 and Y2 can be repositioned by dragging the mouse
while depressing the left or right mouse buttons respectively
Close window
Voltage probe
Current probe
Run Pspice icon
icon
Toggle cursor on
Icon – small shape
Slide to resize window and display cursor data
ICON
crosshair