LM3478: AN-1286 Compensation for the LM3478 Boost Controller

Ye Zhao1

Prodigy 80 points

Part Number: LM3478
Other Parts Discussed in Thread: LM5022

In AN-1286 Compensation for the LM3478 Boost Controller

Equation 10 on page 4. Is there a factor of 0.5 missing in the denominator?

See attached.

Thank you!

over 4 years ago

0 Brigitte over 4 years ago

TI__Guru 61675 points

Hello Ye,

The pole from the output capacitor and the load resistance is without 0.5 in the denominator. Why do you think that this should be there?

0 Ye Zhao1 over 4 years ago in reply to Brigitte

Prodigy 80 points

hello Brigitee

Could you check the equation in the datasheet of LM5022?

https://www.ti.com/lit/ds/symlink/lm5022.pdf?ts=1594669189791&ref_url=https%253A%252F%252Fwww.google.com%252F

Thanks

594669189791&ref_url=https%253A%252F%252Fwww.google.com%252F

0 Brigitte over 4 years ago in reply to Ye Zhao1

TI__Guru 61675 points

Hello Ye,

Please let me clarify this. I will need some days to get back to you.

0 Ye Zhao1 over 4 years ago in reply to Brigitte

Prodigy 80 points

OK. Sounds good. Thanks

0 Brigitte over 4 years ago in reply to Ye Zhao1

TI__Guru 61675 points

Hello Ye,

I am sorry for the confusion. It seems that the app note of LM3478 is wrong and the 0.5 you mention is missing. I learned in the meantime that the 0.5 is coming from the slope compensation in a current mode controller.

0 Ye Zhao1 over 4 years ago in reply to Brigitte

Prodigy 80 points

OK. Thank you. Please update the app note if you can.

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LM3478: AN-1286 Compensation for the LM3478 Boost Controller