feedback/inductors questions

[sss]

hello guys , i got a simple question

i got a push pull smps running from 12V (car) and the out is -+30V
so i want to put output inductors .....
now the problem is :
output inductors - before or after the filtering caps?
where to take the feedback signal - before or after the inductors?


thanx

 

[Eva]

It depends on what you want to get. Do you want a true transformer-coupled regulated buck converter, or you want a pi-filtered output with low-quality regulation based on transformer leakage inductance?

 

[sss]

hello Eva

i want to be able to controll the output voltage , thats why i want to use feedback
i want the output to be as clean as possible , thats why i want to add inductors

 

[Eva]

But in that topology there are at least two ways to control output voltage. This is what I was trying to point out.

 

[sss]

can u explain plz ?
i want to run couple of amps and see what will fit best , so every amp needs a different supply voltage , i dont want to deal with turns ratio ...
anyway, whats wrong with feedback?
if my output voltage is higher then needed and i'll reduce it using feedback so under heavy loads the duty cycle will increase so the output voltage will remain constant .....am i wrong?