Operating Point not found

Conor Ward

Other Parts Discussed in Thread: TPS54140, TINA-TI

I am trying to run a simulation of a circuit using TINA TI Verion 9.1. My circuit involves a TPS54140 IC.
I have various versions of the circuit layout for this component but it keeps giving me an error "Operating point not found" when trying to run a DC analysis - calculate nodal voltages if I go above a certain input voltage. For example, the sample circuit on the TI website (Shown below) which I kept exactly the same only works up to 7.4V. Anything above that and I get "Operating point not found".
Anyone have any ideas on this, I thought it might be my circuit layout but surely it shouldn't be a problem on the sample model?
Thanks,
Conor

over 14 years ago

0 Britt Brooks - Online Design Tools over 14 years ago

TI__Mastermind 41310 points

Conor,

I have run the example circuit at 42V Vin with the DC Analysis --> Calculate nodal voltages and do not get the error you have mentioned. What puzzles me is what you are hoping to find with the DC analysis of the transient model. The test bench is a transient simulation. At time=0 (DC), there are no interesting nodal voltages (Vin is still at 0V). If you use the Table of DC results, you will see that many are values in the E-66V range.

If you follow the instructions in the Simulation Info section, you will see the transient simulation results. The notes states 15 minutes to run, however, the circuit is running in about 3 minutes on my machine (the timing in the note is from TINA-TI v7).

Britt Brooks

0 Conor Ward over 14 years ago

Prodigy 40 points

I just used the nodal voltages as an example none of the analysis will work for me. If putting 42V as Vin works for you but doesn't for me for that exact circuit then there must be a bug in my particular program?

0 Nikhil Gupta (Product Folder Models) over 14 years ago in reply to Conor Ward

TI__Mastermind 39210 points

Conor,

Can you provide your .TSC file?

Nikhil

0 Conor Ward over 14 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 40 points

I am using Version 9.1.30.94 SF-TI
The forum won't let me attached the .tsc file, "File format not allowed".

0 Rick Downs - WEBENCH Design Center over 14 years ago in reply to Conor Ward

TI__Expert 5515 points

Hmmm... I can attach .tsc files, so not sure why you're getting this message.

Zip it up and post the .zip file. Sorry for the inconvenience - I'll look into it.

0 Conor Ward over 14 years ago in reply to Rick Downs - WEBENCH Design Center

Prodigy 40 points

8863.tps54140_tina-ti_steady_state_reference_design.zip

Here's the zip of the file. It's just the example one that was downloaded off the TI website.

0 Neil Albaugh over 14 years ago in reply to Conor Ward

Genius 5430 points

Conor;

I ran your circuit with a 28V supply voltage and a transient simulation also gave me an "Operating point not found- Component: U1.X_U296.D_D11".

I don't have much confidence in some of the TI macromodels and to make the situation worse they have been encrypted! Now, why anyone thinks that it is necessary to keep a macromodel secret is beyond me.

A steady-state analysis did not give me the same error message.

0 Nikhil Gupta (Product Folder Models) over 14 years ago in reply to Neil Albaugh

TI__Mastermind 39210 points

Conor,

I am not sure why you are getting the "Operating point not found" error. I ran the circuit that you attached and it is running fine for me. I am using the exact same version of TINA-TI that you are using. Please see the result below.

Best regards,

Nikhil

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Operating Point not found