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Adding transient simulation top generate the operating point of a circuit |
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The operating point of a circuit has to be established before a transient, ac, |
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or noise simulation may be started. |
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The procedure, as found in cktop.c is as follows: |
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1) Iterate the matrix with the starting values |
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If this fails: |
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2) Start gmin stepping |
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If this fails: |
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3) start source stepping |
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If this again fails, bail out. |
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In tghis branch a fourth method is added: |
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4) Start a transient simulation for a specific amount of time. |
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Keep all data local. Keep the matrix values as an |
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operating point for the simualtion following. |
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If this fails, finally stop. |
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The time for transient is determined a priori. If a transient |
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simulation follows, choose 100 time the TSTEP value. If an ac |
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or noise simulation follows, take the invers of the starting |
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frequency divided by 10 as the optran simulation time. |
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A method to stop the op transient simulation, when all nodes |
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have become stable, might be good, but has not yet been implemented. |
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Step 1 may be skipped by |
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option noopiter |
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Step 2 may be skipped by |
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option gminsteps=0 |
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Step 3 may be skipped by |
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option srcsteps=0 |