half bridge converter transformer design help

[aruna1]

Hi
I have to design and built a half bridge converter with following specifications

Vin = 12V-24V DC
Vout=6V DC
Iout=4A
switching = 100kHz

Can some one tell me how to calculate and design required transformer? I found some info on internet but none of them are usable because they require additional info that I don't have.
I have no idea about this and no additional data is available..if some one can give me or point me to all equations required to design the transformer it would be a great help.
thank you

[waltr]

That is not a trivial task. Try starting with the data sheet for the PWM controller chip that you plan to use then dig into the manufacturer's web site for application notes.
Check Linear Tech's App note 19 for starters on transformer design.