Pseudo transient analysis?

[Mike2]

Starting Gmin stepping.
Warning: Gmin stepping failed.
Starting source stepping.
Warning: Source stepping failed at 0.338231(6.5253e-16)
Starting pseudo transient analysis.
Pseudo transient analysis failed at t=0
Warning: Using skipbp

Total elapsed time: 1.32601 seconds.

Can someone explain what is pseudo analysis here? Why my model is facing this issue?

[KSKelvin]

Your circuit has difficulty in finding a DC solution for .tran to begin with. SPICE, in general, goes through four methods to resolve the DC solution (e.g. if Direct Newton failed, goto Gmin Steeping, then Source Stepping, then Pseudo Transient). Solve with Pseudo Transient indicates that what you are working on poses quite a challenge in obtaining a DC solution.

An example case as your reference.

Incorrect voltage at voltage source

For example, if we specify an initial condition for V(pos) and V(neg), we can prevent this circuit from encountering difficulty in resolving the DC solution and produce a correct DC result. [image] For your information, in the output window, it indicates that Direct Newton iteration, Gmin Stepping, and Source Stepping all failed to find a DC solution without .ic or uic. It eventually resorts to a Pseudo Transient analysis solution and provides an incorrect V(5V). Anyhow, this circuit has been…

[Mike2]

I have tried all .option but still the issue persists. It is working with .UIC in .tran statement but wrong results.

[KSKelvin]

UIC skips the initial condition (DC condition) calculation and start the simulation in an incorrect DC condition to see if simulation works, so you won’t encounter any kind of DC solver warning.