Now I need to design new power device for SDH and system condition as follows. I think its had master to help me to try do this or provide new idea to me.
system condition
1.Input Voltage range:36~72;Regular Voltage 48
2.Ouput voltage :3.3V
3.Output power : 15 w
4.Output circuit :below 8A
If you not need isolate, you can use buck topo to do it,But if you need isolate,active clamp is best topo.ti power supply seminar have classic articles about this topo.
But there had some key word made me confusing "back topo" or "front topo". I could understand what's real means. so anybody could explain more detail about it.