SMPS Output filter inductor calculation.

[corrieb]

Hi All,

I am a brand new newbie when it comes to smps.

I am making a smps for a car audio amplifier , I have read a lot on smps design but can't find anything related to the designing of the output filter inductors. Can anyone perhaps help me with a formula/calculation?

Thank you,

corrieb

 

[sagarverma]

i have built a 300w smps.o/p inductors not used.i/p 12v passes thru 100uh inductors.hope this helps.

 

[sss]

i think bigger= better for those inductors (not too big )
u can take some iron powder cores with 10 turns of wire (thick), this works for me

 

[corrieb]

Thanks for the replies I will go and try tonight.

corrieb

 

[buloi123]

L=Ton*(Vin-Vout)/0.3Iout

The bigger the inductor, much better, for it can fixed more ripple current. But be careful w/ your inductor, as you increase your inductor value, the current capacity and saturation current of your inductor also decreases.

 

[sss]

if u are using output inductors where do u take the feedback signal? after or before the inductor?

 

[corrieb]

SSS,

I take the feedback after the inductor, other wise I am struggling to regulate the smps. why?


corrieb

 

[sss]

SSS,
why?

because i'm also building one and dont know whats better
also , do u put the filter caps after or before the inductors?