smps full bridge
Hi
Take a look at darla1 post, this contains a schematic which will give you a head start with a full bridge design, there is an error in the phasing of the parallel fed driver transformers which you will need to correct, the windings on each transformer should be opposite phase for each side of the bridge, not as shown, but this circuit seems to work according to the thread.
You will have to design your own custom magnetics of course, this is not easy but as noted by other contributers, there are lots of app notes out there to help.
85% efficiency is not very easy to achieve at this power level, you will certainly need to look at synchronous rectifiers to get near to it, the above circuit does not use them incidentally.
Best regards,
Bob.