TINA/Spice/LM5085: EMI of TI's DC/DC

Olivier DI BELLA

Part Number: LM5085
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Hi,

I am a new user of TINA TI Spice simulator.

I usually use LTPSICE but i would like to use TI spice model into TINA in order to simulate EMI of the LM5085 DcDc PFET buck converter.

I created the full schematic and I place the LM5085 transient model :(bottom of this dialogue window)

When I want to check the output transient voltage (VM1) I have 0V DC instead of square waveform with overshoot.

So, I wonder if this is could be caused by the importation of TINA spice model of LM5085.

Do you have a generic protocol in order to create a new TI component and associate its TINA spice file ?

Thanks a lot for your answers,

Sincerely,

Olivier D.

LM5085_switching_emissions.TSC

over 6 years ago

0 Saket over 6 years ago

TI__Intellectual 2680 points

Hi Olivier,

I found that switching node is connected to ground in your schematic and this is forcing VOUT node to be 0V.

I added the diode (used in asynchronous buck converter) in this place and now simulation results seems to be proper.
PFA schematic below.

LM5085_switching_emissions_MOD.TSC

For your question "Do you have a generic protocol in order to create a new TI component and associate its TINA spice file ?"

Yes, we have the document and video training available at below links.

Please let me know if you have any queries on this.

Regards,

Saket

0 Olivier DI BELLA over 6 years ago in reply to Saket

Prodigy 90 points

Hi,

Thanks a lot for your answer.

Indeed, I did not place a diode under the MOSFET transistor, because I wanted a Schottky diode but when the software was compiling there was a mistake.

Concerning the simulator signal, you put "piecewise linear" generator, but is it possible to view the overshoot in output with its signal ?

Moreover, do you know if TI proposed EMI reduction techniques for this chip ? (especially in the feedback loop ?)

Regards,

Olivier D.

0 Nikhil Gupta (Product Folder Models) over 6 years ago in reply to Olivier DI BELLA

TI__Mastermind 39210 points

Hi Oliver,

Regarding the following,

"do you know if TI proposed EMI reduction techniques for this chip ? (especially in the feedback loop ?)"

I have spawned off a related question at the following location so the right team can address this for you:

e2e.ti.com/.../681864

0 Olivier DI BELLA over 6 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 90 points

Hi,

Thanks a lot for your availability !
I will take a look in the related section.

Olivier D.

0 Nikhil Gupta (Product Folder Models) over 6 years ago in reply to Olivier DI BELLA

TI__Mastermind 39210 points

Hi Olivier,

The product line has responded to your query. Please have a look and respond back to that post if you have any followup questions.
e2e.ti.com/.../2511992

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TINA/Spice/LM5085: EMI of TI's DC/DC