TPS54541 Fco calculation

Mauricio Solis Jr

Hi Team,

I am trying to calculate the correct components for the compensation circuit. I use the formulas to calculate Fco1 and Fco2 but see no formula to calculate Fco (Sections 8.2.1.2.10 of the datasheet).

How is Fco calculated? It is used to solve for the resistor used in the Compensation circuit.

Thank you,

Mauricio Solis

over 8 years ago

0 JohnTucker over 8 years ago

TI__Guru**** 191445 points

You pick the Fco to be in between Fco1 and Fco2. Usually you will use the geometric mean as a starting point. then you can fine tune the compensation based on measured loop response of your initial circuit.

0 SheldonTT over 8 years ago in reply to JohnTucker

Prodigy 225 points

What should i look for to properly tune this circuit? Is there a white paper on this subject?

Thank you,
Sheldon

0 JohnTucker over 8 years ago in reply to SheldonTT

TI__Guru**** 191445 points

After you apply the basic compensation, you can measure the loop to see if therei s available phase gain to increase teh loop BW or if the phase margin is too low and the BW needs to be lowered. the calculated values are an estimate meant to get you in the ballpark.

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TPS54541 Fco calculation