LM5117-Q1: Convergence Failure when simulating synchronous buck regulator LM5117Q

Hassan Abdelgabir

Part Number: LM5117-Q1
Other Parts Discussed in Thread: CSD19537Q3, LM5116

Attached are the simulation files (not sure if it is attached properly!)

Could any one help with fixing this convergence error! I have tried multiple tweaks tp get my synchronous buck simulation up and running and still I am get this convergence error. I used auto converge, pulsed voltage source, cap and inductor initial conditions, reduced step size, reduced accuracy ...etc.

And I still get the error: ERROR(ORPSIM-15138): Convergence problem in Transient Analysis at Time = 18.19E-24.2.cir

over 2 years ago

0 EricLee over 2 years ago

TI__Guru 60971 points

Hello Hassan

Would you please zip your simulation files (except '.DAT' )and post it here ?

-EL

0 Hassan Abdelgabir over 2 years ago in reply to EricLee

Prodigy 10 points

2.out.zip

Sure. Here is attached the files

0 EricLee over 2 years ago in reply to Hassan Abdelgabir

TI__Guru 60971 points

Hello Hassan You haven't included DSN file in the ZIP file.-EL

0 Hassan Abdelgabir over 2 years ago in reply to EricLee

Prodigy 10 points

ML_SYNCH_BUCK.zip

Sorry about that. here is attached the zip file with dsn file

0 EricLee over 2 years ago in reply to Hassan Abdelgabir

TI__Guru 60971 points

Hello Hassan The DSN file is broken. -EL

0 Hassan Abdelgabir over 2 years ago in reply to EricLee

Prodigy 10 points

Oh! Not sure why that is! Can you try this one.ML_SYNCH_BUCK_0.zip

0 EricLee over 2 years ago in reply to Hassan Abdelgabir

TI__Guru 60971 points

Hello Hassan This DSN file is broken too. -EL

0 EricLee over 2 years ago in reply to EricLee

TI__Guru 60971 points

Hello Hassan.

Usually, the convergence error is not caused by the device model, but it is caused by the MOSFET model. Would you please try 'Voltage controlled switch' rather than MOSFET model ?

-EL

0 Hassan Abdelgabir over 2 years ago in reply to EricLee

Prodigy 10 points

Files are working properly on my side, not sure why you find it broken.

I see! the thing is I am trying to simulate the losses of this MOSFET (CSD19537Q3) in particular, that is my main purpose! Is there other tweaks you suggest?

Thanks

+1 EricLee over 2 years ago in reply to Hassan Abdelgabir

TI__Guru 60971 points

Hello Hassan

The LM5116 model doesn't support accurate MOSFET driver enough to check the MOSFET power loss. The MOSFET driver is modelled as a simple resistor pull-up and resistor pull-down.

-EL

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LM5117-Q1: Convergence Failure when simulating synchronous buck regulator LM5117Q