EEVblog Electronics Community Forum

Electronics => Projects, Designs, and Technical Stuff => Topic started by: prasimix on May 01, 2018, 08:42:48 pm

Title: Assistance for finding flyback transformer with 3 outputs are needed
Post by: prasimix on May 01, 2018, 08:42:48 pm
I have a thought time trying to find off-the-shelf flyback transformer for wide AC input (e.g. 85-250 Vac) with three outputs and one aux/bias (or four depends how you are counting them). Total power is not more then 7-8 W but it can be up to 20 W. Many of them are with single or two outputs. Actually I'm wondering how are you searching for such parts: I tried with DigiKey and Mouser but resulted list are very narrow. I assume that standard procedure is to order customized transformer, but I'm not sure how economical is that for small series (below 100 pcs). Hence I'd like to adopt design to ready made part. My target output voltages are 2 x 6-9 V (that will be regulated down to 5 V), and one that is isolated from first two and can be anything from 10 to 25 V. Aux/bias should be 12-20 V.  Thanks in advance.
Title: Re: Assistance for finding flyback transformer with 3 outputs are needed
Post by: jbb on May 01, 2018, 09:58:52 pm
Well, you certainly can get custom transformers designed and prototyped. I know that Marque Magnetics will do it, but they are in New Zealand and could be a little expensive when you consider shipping. They can do a full design and propose bobbins, cores etc. to suit. They also can give you a report on the construction and do a HiPot test on every part, which is reassuring.

I’m sure you can find someone closer, but Marque can be a backup for you.
Title: Re: Assistance for finding flyback transformer with 3 outputs are needed
Post by: eliocor on May 02, 2018, 12:11:50 am
Maybe one of those?
https://www.coilcraft.com/transsel_ac.cfm (https://www.coilcraft.com/transsel_ac.cfm)
Title: Re: Assistance for finding flyback transformer with 3 outputs are needed
Post by: T3sl4co1l on May 02, 2018, 02:49:24 am
You may find it's more effective to buy a module (already meets regs!) and put some DC-DC converters after it.  Also, why do a PS from scratch in such quantities when you need regs all the same? :-//

Tim
Title: Re: Assistance for finding flyback transformer with 3 outputs are needed
Post by: BrianHG on May 02, 2018, 03:04:33 am
You would need to filter through these: https://www.digikey.com/products/en/transformers/switching-converter-smps-transformers/168?FV=15c40064%2C15c40066%2C15c40069%2C15c4006a%2C15c4006c%2C15c40072%2C15c40076%2C15c40077%2C15c4000c%2C15c4007b%2C15c40089%2C15c4000e%2C15c4008c%2C15c40090%2C15c40098%2C15c400a6%2C15c400af%2C15c400b1%2C15c400b3%2C15c400ba%2C15c40013%2C15c40015%2C15c40017%2C15c40018%2C15c40022%2C15c40024%2C15c4002f%2C15c40033%2Cffe000a8%2C2dc1823&quantity=&ColumnSort=1000011&page=1&stock=1&nstock=1&k=switching+transformer&pageSize=100&pkeyword=switching+transformer (https://www.digikey.com/products/en/transformers/switching-converter-smps-transformers/168?FV=15c40064%2C15c40066%2C15c40069%2C15c4006a%2C15c4006c%2C15c40072%2C15c40076%2C15c40077%2C15c4000c%2C15c4007b%2C15c40089%2C15c4000e%2C15c4008c%2C15c40090%2C15c40098%2C15c400a6%2C15c400af%2C15c400b1%2C15c400b3%2C15c400ba%2C15c40013%2C15c40015%2C15c40017%2C15c40018%2C15c40022%2C15c40024%2C15c4002f%2C15c40033%2Cffe000a8%2C2dc1823&quantity=&ColumnSort=1000011&page=1&stock=1&nstock=1&k=switching+transformer&pageSize=100&pkeyword=switching+transformer)

However, Alibaba will be cheaper, but, you cant guarantee a lifetime of availability and sometimes you will end up with junk. EG:
https://www.alibaba.com/product-detail/12V-24V-120V-EE13-EE20-High_60785844052.html?spm=a2700.details.maylikever.12.43c963a6ucB6v7 (https://www.alibaba.com/product-detail/12V-24V-120V-EE13-EE20-High_60785844052.html?spm=a2700.details.maylikever.12.43c963a6ucB6v7)
https://www.alibaba.com/product-detail/EE-EI-EF-EER-EFD-ER_1007814385.html?spm=a2700.details.maylikever.6.66f0e5a89aRWAd (https://www.alibaba.com/product-detail/EE-EI-EF-EER-EFD-ER_1007814385.html?spm=a2700.details.maylikever.6.66f0e5a89aRWAd)
Now, you cant beat those prices.  Also, you can order custom windings.

Title: Re: Assistance for finding flyback transformer with 3 outputs are needed
Post by: prasimix on May 02, 2018, 06:44:22 am
Thanks a lot for all your replies. Coilcraft has two parts but with connected secondaries. On Mouser (similar to Digikey) I already found 750811914. I'll give a try to mentioned manufacturers listed on Alibaba, too.
Title: Re: Assistance for finding flyback transformer with 3 outputs are needed
Post by: prasimix on July 02, 2018, 04:03:38 pm
An update: I had contacted Feryster (http://feryster.pl/) from Poland regarding custom solution but also a few Chinese manufacturer found on Alibaba as has been suggested from some of you. Neither of Chinese manufacturer came back with quotation or positive answer. But, Feryster made a great job and for great price (I believe that is very competitive with Chinese manufactures). Here is the result, it works like a charm but more about that in other thread.

(https://i.imgur.com/7YyXI6u.jpg)