Finding DC operating points at certain timepoints during TRANSIENT analysis

Essentially each point in the transient is a solved "operating point" - and what infotimes is doing is just writing out the data at the already solved bias conditions.

To do what you want, I think the only possible option is to run a transient simulation to the time you want, and use writefinal to write out a nodeset file which contains the voltages and currents. You could then run a dc with this as an initial condition file (readforce) and also to enable the force=all option to allow initial conditions to be used in a DC. However, I doubt this really is what  you want - because that would hold the initial conditions from the file during the DC and so the resulting DC would essentially be the same as what was in the file. If instead you used readns on the dc analysis, I'm not sure this proves very much, because all the voltages would move away from the original values to reach a settled steady-state condition.

There used to be an option in transient to "checkpoint" the operating point voltage/currents at times during the simulation, which was used in the past as a means of recovering from a previous time. However, it wasn't very robust so that was dropped in favour of the save/recover options which write a much more complete representation of the state at a timepoint.

So I don't think you can really do what you are trying to do here. You're expecting selected capacitors to discharge, but not others...

The transient is not necessarily going to take a long time to simulate if there's no signal activity when you've gone into power down mode - although if you've got clocks switching, those will cause the simulator to still take timesteps, so maybe it's not so easy).

Regards,

Andrew.

Essentially each point in the transient is a solved "operating point" - and what infotimes is doing is just writing out the data at the already solved bias conditions.

To do what you want, I think the only possible option is to run a transient simulation to the time you want, and use writefinal to write out a nodeset file which contains the voltages and currents. You could then run a dc with this as an initial condition file (readforce) and also to enable the force=all option to allow initial conditions to be used in a DC. However, I doubt this really is what  you want - because that would hold the initial conditions from the file during the DC and so the resulting DC would essentially be the same as what was in the file. If instead you used readns on the dc analysis, I'm not sure this proves very much, because all the voltages would move away from the original values to reach a settled steady-state condition.

There used to be an option in transient to "checkpoint" the operating point voltage/currents at times during the simulation, which was used in the past as a means of recovering from a previous time. However, it wasn't very robust so that was dropped in favour of the save/recover options which write a much more complete representation of the state at a timepoint.

So I don't think you can really do what you are trying to do here. You're expecting selected capacitors to discharge, but not others...

The transient is not necessarily going to take a long time to simulate if there's no signal activity when you've gone into power down mode - although if you've got clocks switching, those will cause the simulator to still take timesteps, so maybe it's not so easy).

Regards,

Andrew.