Electronics > Beginners

Choosing off the shelf transformers for flyback converters

(1/3) > >>

Arznei:
Hello,

I am currently trying to learn a bit about switch-mode power supplies and DC/DC converters in general. I am however having a real hard time actually finding off the shelf transformers. Let's say I plan on having a 24VDC input for my circuit and I need 3 seperate 5VDC rails in my design, 2 of which need to be isolated from the 24VDC input. How would I go about finding a flyback transformer that suits those criteria?

I tried looking through the webpages of coilcraft and the likes, but I barely ever find a transformer that has 3 "secondary" windings and much less one that is suited for 24DC input and happens to have 3 secondary windings all specified for 5VDC output.

Is there some site where I could go about a parametric search for transformers? Or is the only way out a custom transformer?

Thank you for any help!

Benta:
Unless it's a very, very simple transformer, it's custom every time. Ferrite grade, saturation curves... you name it.

Have fun in the wonderful world of magnetics. Been there, done that. 

TimNJ:
As Benta said, almost always custom. Transformer design varies a lot between power supplies. Depends on the topology used, controller, input/output voltage and current, physical form-factor, etc. There many be some off-the-shelf offerings but they probably won't be just right.

Making your own transformer actually isn't all that hard. Just need magnet wire, maybe some triple-insulated wire (TIW), 3M 1350 polyester tape, and core/bobbin set.

coppice:
If you can find an application note or EVM from a silicon vendor which matches your needs, you often find that the transformer in it was made by a well known winder of coils. Often, the coil winder has given this a part number, and made it available to order.

spec:
Hi Arznei,

As the other members say for a special application you would need to have the fly back transformer made to suit. But there are hundreds of 'standard' fly back transformers available, one of which may suit your purpose which is fairly standard.

There are also a load of standard fly back circuits, both on the net generally and in manufacturers chip datasheets and application reports.

The other thing you could do is modify an existing SMPS, especially computer PSUs which are powerful and cheap.

https://www.google.co.uk/search?q=flyback+transformer&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj4m7zJwpvfAhVdSBUIHfEJBZUQ_AUIDigB&biw=1333&bih=602&dpr=1.2#imgrc=_

https://www.digikey.co.uk/products/en/transformers/switching-converter-smps-transformers/168?k=flyback%20transformer

https://katalog.we-online.com/en/ctm/switch/mid_power_magnetics/mid_dc_dc_flyback_transformers

Navigation

[0] Message Index

[#] Next page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod