LP8867-Q1: Is CFB for preventing oscillation of internal amplifier?

Yoshiki Ochi

Part Number: LP8867-Q1

Hi team,

Is CFB for preventing oscillation of internal amplifier?

"8.3.1.2.3 Feedback Capacitor" says CFB is needed if fsw is high such as 2.2MHz. I guess it is related to phase compensation, is it correct?
And this is why CFB is not needed if we use fsw=400kHz, is it right?

Regards,
Ochi

over 5 years ago

0 Frank Qiu over 5 years ago

TI__Genius 15776 points

Hi Ochi-San,

The CFB is used to add a zero and pole to the loop, and it used to confirm the loop stability.

0 Yoshiki Ochi over 5 years ago in reply to Frank Qiu

TI__Genius 9495 points

Hi Frank,

Thank you. I understood CFB is for loop stability.

But I have a lack of knowledge of loop stability.
Do you have good training resources for that?

Regards,
Ochi

0 Frank Qiu over 5 years ago in reply to Yoshiki Ochi

TI__Genius 15776 points

Here is a boost loop study materials and you can search "peak current control mode"in IEEE for more informationpractical feedback loop analysis for voltagge-mode boost.pdf

0 Yoshiki Ochi over 5 years ago in reply to Frank Qiu

TI__Genius 9495 points

Hi Frank,

Thank you very much!

Regards,
Ochi

0 Frank Qiu over 5 years ago in reply to Yoshiki Ochi

TI__Genius 15776 points

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LP8867-Q1: Is CFB for preventing oscillation of internal amplifier?