User Guide

Chapter A Setting initial state
378
Setting initial conditions
The IC property 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 property defined start with the specified voltage or
current value; however, all other such devices have an
initial voltage or current of 0.
Note Skipping the bias point calculation can make the transient analysis
subject to convergence problems.
Applying an IC property for a capacitor has the same
effect as applying one of the pseudocomponents IC1 or
IC2 across its nodes. PSpice attaches a voltage source with
a 0.002 ohm series resistance in parallel with the capacitor.
The IC property 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
attaches a current source with a 1 Gohm parallel resistance
in series with the inductor.
See
Setpoints
on page A-376
f
or
more information about IC1 and IC2.
Pspug.book Page 378 Wednesday, November 11, 1998 1:14 PM