Feedback Loop calculation for SMPS with secondary LC output filter

Also, on page 10, the expression for "wop"....is that now the output pole frequency of the SMPS?....and the original pole , (before the LC was added), is now to be
discarded?
And since when the LC filter is added, there are now effectively the two capacitance banks (either side of the inductor)...so are there now two ESR zero's in the transfer function.?..one for the upstream cap, and one for the downstream cap?

In fact, Fig 15 of this article is obviously nonsense....both plots are the same...even though ESR is different....this article is very festered with mistakes...does anyone have a better article on the bode plots for an SMPS with a post LC filter?

Also, on page 10, it has the zero expression for the esr zero...and appears to suggest that this is referring to the downstream cap of the LC post filter....this just doesnt seem right.........the power stage will be "viewing" this ESR through the inductor of the LC post filter, so it wont particularly be able to even "see" this ESR.... and thats not even mentioning the esr of the post filter inductor.

I think this article is way off the mark.

cupoftea said:

Hi,
Do you agree, the expression for "wop" at the bottom left of page 10 should not be square routed?

Click to expand...

omega= (LC)^-2 is correct
also series equiv. of 2 caps is correct