How to calculate the pulse transform

[tocal09]

I have several transform in AT&ATX power supply . Now I want to make my switching power supply but I don't know how to calculate the transform . Help me

 

[IanP]

You need to know what is the switching frequency..
Next, remove primary and secondary and count turns..

In your design you can use the same (or close to) switching frequency and similar number of turns for the primary. With secondary you will have to experiment a little bit...

 

[tocal09]

If I use frequency near to the old freaquency ---> calculate my primary and secondary ... = primary :no chance ;
secondary: number turn of the new/number turn of the old = Vout (new)/Vin (old) and experiment a little bit... ??Am I right?

Frequency use in this type of power supply is about 40kHz-50kHz ,isn't it?

 

[tocal09]

Nobody answer me . but I want to find all book about this .Is there any in our forum?

 

[VVV]

I can help with transformer design, but you should start here https://focus.ti.com/docs/training/catalog/events/event.jhtml?sku=SEM401014

Then, if you have questions, please ask me.

I do not know any electronic book, but the book I found most useful about switching power supplies is the one by Abraham I. Pressmann, I think it's called Switch-mode power supply deisgn. I only have an older edition, the new one includes PFC's as well.
There is also another book, with a similar name, by Keith Billings. However, Pressmann's book is the only one that you can use to actually DESIGN a power supply, even if it has some shortcomings.
These books are rather expensive, though.

Also, keep searching the TI website for Unitrode seminars (TI bought Unitrode in 1997, I think). See the link above, too.