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Auto loadbias and savebias for stepped simulations


 

I recently asked Mike if would be possible to add a new feature to .savebias and .loadbias invoked by the keyword ¡°eachstep¡± whereby in a stepped simulation, each succeeding step would load the bias saved by the preceding step.? Among other uses, this could allow eliminating the startup transient between steps when performing a time domain frequency response analysis.


Currently bias data may be saved from individual steps, but the syntax is cumbersome as each step must be specified:


.savebias bias1.txt time=1m step=0
.savebias bias2.txt time=1m step=1
.savebias bias3.txt time=1m step=2


Unfortunately, there is no way to load different bias data for steps, which is the reason for my request to Mike.


Yes, I realize that .savebias type commands do not save branch currents (inductor states), but that may be neatly circumvented by creating a simple inductor subciruit that converts a capacitor into its dual via controlled current sources. (I posted this a few days ago.)


.subckt L 1 2

.param L=1 Rser=1m Rpar=1/Gmin

C1 3 0 {L} Rser={1/Rpar} Rpar={1/Rser}

G1 1 2 3 0 1

G2 3 0 2 1 1

.ends L

?

Merry Christmas and a Happy New Year


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