LM5116: Transient simulation of LM5116 in SIMetrix

Ryan Rah

Part Number: LM5116

Tool/software:

I created a model of LM5116 for SIMetrix software and did the schematic for transient analysis but the model is not working properly.

the problem in the simulation is that HO is always high and LO is always low, means that high side switched from beginning is ON and nothing is switching in the simulation!

I followed datasheet recommendations and quick start sheet to set the parameters.

Can you please support me to debug the problem and why it is not working!

The simulation schematic and LM5116 library model are attached!BUCK_LM5116_draft.zip

5 months ago

0 EricLee 5 months ago

TI__Guru 58371 points

Hello Ryan

The library file you are using is PSPICE library. Please convert to SIMETRIX library based on the PSPICE library.

-EL

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

Thanks Eric,

Can you please help me to create model from your side!

0 EricLee 5 months ago in reply to Ryan Rah

TI__Guru 58371 points

Hello Ryan

TI has a standard model development procedure. It takes about 2-3 months to finish. And cannot be started unless the resource is assigned.

If you create the model, then I can help you debugging the error.

-EL

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

Understood!
The simulation schematic and model are included in the attached zip file.
Can you please review the simulation and SPICE library of LM5116 that is being used in the simulation.

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

6013.BUCK_LM5116_draft.zip

0 EricLee 5 months ago in reply to Ryan Rah

TI__Guru 58371 points

Hello Ryan

The IC symbol is missing in your .ZIP file

-EL

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

You should generate the symbol based on LM5116_TRANS.lib file like what I generate with auto generation option.
That is where I need support to make sure I have create the model properly.

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

Sorry for incorrect photo, please find this one that shows LM5116 IC symbol after autogenerate with SIMetrix:

0 EricLee 5 months ago in reply to Ryan Rah

TI__Guru 58371 points

Hello Ryan

Please show me the error message.

-EL

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

There is no error when I start simulation, just as I said, HO pin is always high and LO pin is always low!

input voltage goes directly to output and after some oscillation due to L and C, it gets stabilized!

I am not sure it is because of model that has been created in SIMetrix incorrectly or what it can be!

Along side, is there any example simulation of SIMeteix for LM5116 that can be shared?

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

Were you able to run the simulation and find the root cause of it?

0 EricLee 5 months ago in reply to Ryan Rah

TI__Guru 58371 points

Hello Ryan

I spent about half day but I couldn't find the root cause. One thing I found is that the inductor model you are using is making a weird behavior. After replacing the inductor model with normal basic inductor model, it becomes better. Then, I also found the MOSFET model you are using is generating excessive current. After replacing your MOSFET model with normal voltage controlled switch, I could see a few switching cycles at some condition, but still not working properly

-EL

0 Ryan Rah 5 months ago in reply to EricLee

Prodigy 180 points

The MOSFET and inductors that I used are the same as I used in another simulation that works OK!
I just wanted to make sure the SPICE model has no glitch or syntax error that causes this problem!

0 EricLee 5 months ago in reply to Ryan Rah

TI__Guru 58371 points

Hello Ryan

We haven't released LM5116 model which runs in SIMETRIX (=SIMETRIX model). The modelling takes about 2-3 months and it cannot be started unless the resource is assigned.

-EL

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LM5116: Transient simulation of LM5116 in SIMetrix