User Guide

2
-
12 Primer: How to Optimize a Desi
g
n
Runnin
g
the PSpice Optimizer
You can use the PSpice Optimizer to:
• Optimize the circuit to completion (from the Tune menu,
select Auto).
• Evaluate performance for a single set of parameter values
(from the Tune menu, select Update Performance).
• Compute derivatives of each specification with respect to
each parameter (from the Tune menu, select Update
Derivatives).
When you select Auto from the Tune menu, the PSpice
Optimizer automatically computes the derivatives for each
specification with respect to each parameter (Figure 2-5). Using
the derivatives, the optimizer determines the direction in which
to vary the parameters, and changes parameter values
accordingly until it achieves a reduction in the overall error.
After updating the parameters, the optimizer computes new
derivatives and repeats the process until one of the following
occurs:
• Specifications are met (success).
• No more progress can be made (failure).
• You manually interrupt the process.
This is useful when initially
validatin
g
the circuit or when
restartin
g
optimization after
adjustin
g
parameters or
specifications.
This is useful when explorin
g
desi
g
n tradeoffs by tweakin
g
parameter and specification
values.