half bridge converter transformer design help

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

Ferrite Cores, MPP Cores, Tape Wound Cores, Sendust Cores| Magnetics®

The design catalog download was 4.3 megabytes in 2006 and there are several more megs of parts catalogs. I don't think I'm allowed to upload files that big at this site. These downloads will give you everything you need, if you can understand them. If you can't understand them, talk to your teacher.

#12 said:

Ferrite Cores, MPP Cores, Tape Wound Cores, Sendust Cores| Magnetics®

The design catalog download was 4.3 megabytes in 2006 and there are several more megs of parts catalogs. I don't think I'm allowed to upload files that big at this site. These downloads will give you everything you need, if you can understand them. If you can't understand them, talk to your teacher.

Click to expand...

can you please give me the direct link to this catalog? i couldnt find it in their site

Run your data through National Semiconductors Simple Switcher wizard. You'll get an IC recommendation & schematic.

blueroomelectronics said:

Run your data through National Semiconductors Simple Switcher wizard. You'll get an IC recommendation & schematic.

Click to expand...

hi
i tried switcher wizard designer.but there isnt any way to select half bridge topology