TPS563209: Theoretical bode plot

Kazuki Itoh

Genius 10045 points

Part Number: TPS563209

Hi team,

Is it possible to draw the theoretical bode plot of TPS563209 to estimate PM and GM and then make sure the stability?

The theoretical background of DCAP2 controller is provided by the app note below.

https://www.ti.com/lit/an/slva546/slva546.pdf

But to calculate the compression transfer fucntion Hcomp(s), time constant Tc and voltage compression block coefficient Acp are needed.

Best regards,

Kazuki Itoh

11 months ago

0 Athos Zhao 11 months ago

TI__Expert 7320 points

Hi Kazuki-san,

It's ok to use bode plot for stability analysis.

However, The Acp and Tc are internal parameters and can't be shown here.

To design the external components, you can follow the section 8.2.2.2.1 Output Filter Selection or WEBENCH tool.

0 Kazuki Itoh 11 months ago in reply to Athos Zhao

TI__Genius 10045 points

Hi Athos-san,

I understand Acp and Tc are internal parameters.

I tried TPS563209 WEBENCH tool, but the bode plot, PM and GM didn't show up.

My customer's asking us how to draw the bode plot because it's always better to estimate theoretical PM and GM by using bode plot before the design.

Actually, my customer had to reduce the Cout as the PM didn't meet their internal regulation.

Could you please check that again?

Best regards,

Kazuki Itoh

0 Miranda Gu 11 months ago in reply to Kazuki Itoh

TI__Genius 15587 points

Hi Kazuki-san,

Athos is on public holiday, he will reply you after 2/17. Appreciate your understanding.

0 Kazuki Itoh 11 months ago in reply to Miranda Gu

TI__Genius 10045 points

Hi Miranda-san,

Thank you for letting me know his schedule. Looking forward to receive the update.

Best regards,

Kazuki Itoh

0 Miranda Gu 11 months ago in reply to Kazuki Itoh

TI__Genius 15587 points

Hi Kazuki-san,

Sure, please expect the reply by early next week.

0 Athos Zhao 11 months ago in reply to Miranda Gu

TI__Expert 7320 points

Hi Kazuki-san,

Got your request. We'll check with our design team internally and show you the feedback later.

+1 Harry Zhou 11 months ago in reply to Kazuki Itoh

TI__Expert 3900 points

Hi Kazuki-san,

So sorry to tell the customer that after consulting the designer, we cannot provide parameters beyond the datasheet. However, the values of Tc and Acp can be deduced through actual testing. If the customer can accept the calculated results, we can help test and give this value.

Best regards,

Zhou

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TPS563209: Theoretical bode plot