User`s guide

A
-
6 Settin
g
Initial State
Settin
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Initial
Conditions
The IC attribute allows initial conditions to be set on capacitors
and inductors. These conditions are applied during all bias point
calculations. However, if you select (
✓) the Skip Initial
Transient Solution check box in the Transient Analysis Setup
dialog box, the bias point calculation is skipped and the
simulation proceeds directly with transient analysis at TIME=0.
Devices with the IC attribute defined start with the specified
voltage or current value; however, all other such devices have an
initial voltage or current of 0.
Note
Skippin
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the bias point calculation can make the
transient analysis subject to conver
g
ence
problems.
Applying an IC attribute for a capacitor has the same effect as
applying one of the pseudocomponents IC1 or IC2 across its
nodes. PSpice A/D attaches a voltage source with a 0.002 ohm
series resistance in parallel with the capacitor. The IC attribute
allows the user to associate the initial condition with a device,
while the IC1 and IC2 pseudocomponents allow the association
to be with a node or node pair.
In the case of initial currents through inductors, the association
is only with a device, and so there are no corresponding
pseudocomponents. The internal implementation is analogous
to the capacitor. PSpice A/D attaches a current source with a 1
Gohm parallel resistance in series with the inductor.
If you want IC attributes to be ignored when Skip Initial
Transient Solution is not enabled in the Transient Analysis
Setup dialog box:
1
Click Options in the Setup Analysis dialog box.
2
Set NOICTRANSLATE to Y.
See Setpoints on page A-4 for
more information about IC1 and
IC2.
See Setting Up Analyses on
page 8-3 for a description of the
Analysis Setup dialo
g
box.