LM5116: Frequency loop analysis for LM5116 based synchronous buck converter In TINA

venkata subash1

Prodigy 85 points

Part Number: LM5116

Hi I need help to do frequency loop analysis of my circuit to check the phase and gain margin of circuit.

what are all parameters we need to add for the current loop of LM5116 IC in the attached model.\

7624.BUCK_CONVERTER_FREQ_ANALYSIS.TSC

over 3 years ago

0 Timothy Hegarty over 3 years ago

TI__Guru 56462 points

Hi Venkata,

You can use the LM5116 quickstart calculator to assist with compensation component selection.

Regards,

Tim

0 venkata subash1 over 3 years ago in reply to Timothy Hegarty

Prodigy 85 points

Hi Timothy,

Thank you for the response.

I want to design the compensation for particular phase margin, i used the webbench design tool for this but i want to check the result in frequency analysis.

0 Timothy Hegarty over 3 years ago in reply to venkata subash1

TI__Guru 56462 points

Hi Venkata,

The quickstart calculator will allow you to do that most efficiently.

https://www.ti.com/tool/LM5116-5116WG-25116DESIGN-CALC

Regards,

Tim

0 venkata subash1 over 3 years ago in reply to Timothy Hegarty

Prodigy 85 points

Hi TIm,

I have used this design calculator,i want to verify the compensation with frequency analysis simulation based on TINA.

For this what are all parameters we need to add for the current loop of LM5116 IC in previously attached model.

0 Timothy Hegarty over 3 years ago in reply to venkata subash1

TI__Guru 56462 points

Ventaka,

I may be able to get our modeling team to take a look. In the meantime, the internal current sense parameters (gain, etc.) are available in the LM5116 datasheet.

Regards,

Tim

0 venkata subash1 over 3 years ago in reply to Timothy Hegarty

Prodigy 85 points

Hi Tim ..Any update from modelling team?

0 Timothy Hegarty over 3 years ago in reply to venkata subash1

TI__Guru 56462 points

Ventaka,

I have informed the modeling team of this. What parameters in the current loop are the main concern so they know what to focus on?

Regards,

Tim

0 Timothy Hegarty over 3 years ago in reply to Timothy Hegarty

TI__Guru 56462 points

Ventaka, in the meantime you might try using WEBENCH to check LM5116 as needed.

Regards,

Tim

0 venkata subash1 over 3 years ago in reply to Timothy Hegarty

Prodigy 85 points

Hi Tim ,

Yes i have used the webbench to check LM5116.

The results with webbench design and LM5116 design calculator are not matching. I tried to put the same values in both cases.

0 Timothy Hegarty over 3 years ago in reply to venkata subash1

TI__Guru 56462 points

Ventaka,

The output cap value is critical. Make sure the ceramic capacitance is derated for applied voltage.

Regards,

Tim

0 Timothy Hegarty over 3 years ago in reply to Timothy Hegarty

TI__Guru 56462 points

Hi Ventaka,

Recommendation is to try the already available PSPICE average model in the LM5116 product folder. All the internal parameters are already modeled as per the requirements. You can adjust the external compensation circuit values to meet your requirements.

Average model link: https://www.ti.com/lit/zip/snvm346

Also here is the link that explains the process of importing from one tool to another -- in this case importing a PSPICE model to TINA:

Link: https://e2e.ti.com/support/tools/simulation-hardware-system-design-tools-group/sim-hw-system-design/f/simulation-hardware-system-design-tools-forum/692613/faq-tina-spice-note-about-encrypted-models-and-importing-models-from-one-simulator-to-another?tisearch=e2e-sitesearch&keymatch=%252520user%25253A50508#

Regards,

Tim

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LM5116: Frequency loop analysis for LM5116 based synchronous buck converter In TINA