Need to help to design the power device

[Tommyliu]

Dear all

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

BR

 

[alphi]

how requirement about effecient/volumn?
I think you can use a forward topo to do it.

 

[Tommyliu]

Dear Alphi

The system efficient is 85% to 91 %

BR
Tommy

 

[janni]

There is a line of National Semiconductor LM50XX 100V PWM controllers. There are very cheap evaluation boards:

**broken link removed**
**broken link removed**

More you can find at National Semi website.

 

[tryagain]

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.

 

[Tommyliu]

Thanks all

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.

BR
Toomy

 

[alphi]

It is not "back" or "front".
It is flyback or forward topology,is basic switch-mode power supply!

 

[rauol]

8) with 8 amps current required by you a forward topology is the best suited for you, a flyback converter will require a larger output capacitor .