UCC28700 Flyback transformer selection

Ye-sheng Kuo

Other Parts Discussed in Thread: PMP8787

Hi,

I'm designing the AC/DC converter. The output is 5 V and 10 W maximum. Given the equation from the datasheet, I found that the transformer should have ~500 uH, 13-15 Nps (Primary to Secondary turns ratio) and ~3 Nas (Auxiliary to Secondary turns ratio). I couldn't found the appropriate transformer from DigiKey/Mouser. Does anyone has suggestion about the transformer which might fit to my application?

Thanks!

Ye-sheng

over 12 years ago

0 Joshua Newell1 over 12 years ago

I also have a similar issue, where the reference design points to a specific renco transformer which is not found on their website.

In particular we are going through the 2.1A 5V USB charger design based around the UCC28700DBV IC found on schematic slur930.pdf.

Can we request the transformer design/ bobbin from TI? ( we already have the number of turns, but we cant find the bobbin anywhere)

Nidan

0 Mike O' over 12 years ago in reply to Joshua Newell1

TI__Guru* 85946 points

These are designed by TI's eLab. I would put a request into them to see were you might be able to get the transformer.

I don't believe the eLab engineers monitor the E2E.

0 Vasiliy Bogatov over 12 years ago in reply to Mike O'

Expert 1500 points

Hi Mike!

Are there any respond about transformer from eLab?

Thanks,

0 Nelson Garcia over 12 years ago in reply to Joshua Newell1

Prodigy 40 points

Joshua:

I am from Renco electronics and we would be happy to assist you. Please send us an email at Engineering@rencousa.com with your questions and we would be happy to assist you.

Nelson Garcia

0 vengadesh uthirapathy over 11 years ago in reply to Nelson Garcia

Intellectual 770 points

Hi Sir / Madam ,

This is vengad here from Avnet India , I am doing the AC/ DC Adopter design based on PMP8787 Ref-design for one of my customer . can you please share the PMP878 ( Flyback RLTI-1084 Renco Electronics) Transformer detals ?

regards/

Vengad

0 Nelson Garcia over 11 years ago in reply to vengadesh uthirapathy

Prodigy 40 points

Vengad:

We would be happy to help. Please send me an email to engineering@rencousa.com and we would be happy to provide you the information you need.

Sincerely,

Nelson Garcia

0 robin gangopadhya over 10 years ago in reply to Nelson Garcia

Intellectual 855 points

Nelson
I did: the d/s for RNTI-1090 strangely does not give turns ratio. The TI app note surely shows an example & we need to uderstand, perhaps model, the circuit before scaling it for other apps. So the turns ratio, inductance values on sec & aux are necessary. cld you post that here ? I am waiting for Christy to reply to my request as well.

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UCC28700 Flyback transformer selection