Transformer for Flyback converter

[hithesh123]

I am new to switching converters. I was looking at powerint.com
They have some neat app notes and ICs for universal input flyback converters.
I was using their software to design a universal input, 22VDC output power supply.
One thing I am not sure is - should the flyback transformer be custom made for a particular design or is it possible to use off the shelf transformers?

 

[keith1200rs]

There are a few off the shelf transformers around, but unless you are lucky you are stuck with having one wound, or winding your own. Power Integrations offer a prototype coil winding service (at a cost), although I have never used it.

Keith.

 

[srizbf]

for switching converters it is very difficult to use an off the shelf one.

one is availability for the rquirement and second most important one is
getting the parameters of the off-the-shelf items.

because if it does not satisfy your inductance and current carrying requirements
you will spend a lot of time finding the source of the problem.

srizbf
21stmay2010

 

[keith1200rs]

There are a few here, for specific designs and chips:



I think most of them are for the demo boards that the chip manufacturers make.

Keith.

 

[electrophysics]

One thing I am not sure is - should the flyback transformer be custom made for a particular design or is it possible to use off the shelf transformers?

In transformer based topoligies it is better to use custom made transformers i.e. your own design as you have to look at some important issues like transformer saturation point, flux imbalance, wound wires current capacity etc.

 

[hithesh123]

Thanks for the reply, guys.
The reason I asked is bcoz I opened up a SMPS and found out the transformer was commercially made - by Hammond. They probably used it to save some $$.
In general, can any transformer manufacturer design these custom cores?