Offline full-bridge SMPS....need help

[luka]

Iron powder core for output sound ok as far as I know
But I don't know why you have 2 inductors after etd, that should be one and after diods, I hope you have it like that

[ravslanka]

hi luka ,

is it ok now
http://img153.imageshack.us/img153/4706/88772179.gif
isnt it primatry providing more current then secondary.

thanks

ravs

be a vegeterian.....

[luka]

yes, if secondary voltage is higher then +/-160vdc in case of 230Vac input

Its better, but this goes for any trace around primary, secondary... see that top right pin of SG that is connected to... that one is close to secondary, while SG is part of primary circuit

[Krisfr]

What size and value of caps would recommend to both of us, Luka?

[luka]

Originally Posted by Krisfr

What size and value of caps would recommend to both of us, Luka?

depends on voltage (size of cap), you can calculate what value you will need for your design (ripple current).

If all that is too much, go for about 3000uF max per rail, that means 3-4 caps. unless you can get low esr caps, then you can get away probably with even less... everything else is done with regulation, if that is what you go for, as I think you do. I can not stress enough, how important compensation is. If done right, you have almost perfect DC on output, independent of load you have

[Krisfr]

I am going to go with 4 CHEAPO 1000uf 100V per rail, then AFTER I build and test it I can take out as much as I can get away with.

The board I am laying out is just to test out everything I want to do before I commit to making a few clones of them...

IS there a site or something that I can use to calculate the inductors based on turns wire gauge material etc... I need to learn that too, what do you recommend...

Thanks

[luka]

note that less is more with switching supplys, no need for bulk capacitance, only on primary if you don't use pfc, on primary I say as much as you can

Site... don't know, but there are several books on this topic

[Krisfr]

Okay I got you... I am down to 2 on out put and up to 4 on INPUT

Which books? Basso? ???

[luka]

Originally Posted by Krisfr

Okay I got you... I am down to 2 on out put and up to 4 on INPUT

Which books? Basso? ???

size on primary, you want as many uF as you can get on board, 60Hz(120Hz) you can't filter on output, so better there is none

Abraham Pressman - Switching Power Supply Design 3rd Edition
Ron Lenk - Practical Design of Power Supplies
Marty Brown - Power Supply Cookbook (2nd ed.)
COLONEL WM. T. MCLYMAN - Transformer And Inductor Design Handbook, Third Edition
and
DESIGNING MAGNETIC COMPONENTS FOR HIGH FREQUENCY DC-DC CONVERTERS, also from him

I mean, there is over few 1000 pages, if you really want to learn

[Krisfr]

Any of those available ON LINE

I just ordered 4 390uf at 450 Panasonic's from the coast...

Thanks a lot