TPS56121: TPS56121 feedback loop compensations values and bode plots

Babak Manou

Part Number: TPS56121

Hello everyone,

I have a question about the compensation tool (www.ti.com/.../sluc263) for feed feedback loop design. I have redesigned my circuit based on 50kHz Fco and 56-degree Phase Margin. My total System Bode plot and Error Amp Bode plot are shown below. I just want to check to make sure that these plots and values are fine.

I have also redesigned the PCB layout very similar to the given layout in the datasheet. However, I removed all the elements on the back on the put them in the main circuit.

Thanks,

Babak

over 6 years ago

0 JohnTucker over 6 years ago

TI__Guru**** 191445 points

Babak,

So far as I know the compensation tool will give good results. It uses "k-factor" method, which I personally use a lot. The component placement generally looks good. I only have your schematic in the office and I am out for the holiday. I can check it more closely on Monday. I may suggest some minor changes.

0 Babak Manou over 6 years ago in reply to JohnTucker

Intellectual 420 points

That would be awesome. Waiting for your feedback and enjoy your holidays. Thanks

0 Babak Manou over 6 years ago in reply to JohnTucker

Intellectual 420 points

Hi John,

Did you have a chance to look at this design? In compensation tool, I also changed the Iout to 15 amps instead of 12A.

Cheers,

Babak

0 JohnTucker over 6 years ago in reply to Babak Manou

TI__Guru**** 191445 points

Babak,

If you are using a 2 layer PCB, you may want to add some extra distance between your input and output capacitors to allow for a wider Ground path. For 15 A, I highly recommend 4 layer design. Even with 4 layers I would move the capacitors a little to allow for vias. Also I would move R2.2 and C2.2 closer to the IC in beween teh IC and inductor. It is important to minimize the SW node copper without making it too thin.

0 Babak Manou over 6 years ago in reply to JohnTucker

Intellectual 420 points

Thanks John. Will test it and keep you posted. Cheers

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TPS56121: TPS56121 feedback loop compensations values and bode plots