need hel with smps txfr .........

[sekhar]

hi everybody,
i am rebuilding a smps . and i need to wind my own txfr according to my need , I have a working circuit which is half bridge topology with a pfc to make the smps universal .
Can some help me in calculating primary and secondary turns and core size for the given smps .....
I need +- 50V @ 5A .....

circuit attached ..............

regards
sekhar

[luka]

I like to use this one, its simple

http://www.classdaudio.co.cc/doc/Off...SMPS/an108.pdf

I start with Step No. 11, coz all the above is not a problem, since I don't go with the smallest cores and specs I could
Once you have Np, secondary is simple to get... for no regulation you use just that, for regulated, you add say about 10% more turns...you could always find that by testing unregulated smps, to see how much voltage drop you get...

[sekhar]

cant anyone help this newbie ..............??????????????/



regards
sekhar

[PedroDaGr8]

Sekhar see Luka's post. It has everything you need. Luka is brilliant in this SMPS stuff. He and the eyeball lady (I am drawing a blank on her name, her avatar is a picture of her eye and I seem to remember she is from spain) are heavily experienced in this field so trust their advice.