UCC28704: Question about AC/DC converter IC for the inductor my customer selected.

Kazuya Nakai59

Part Number: UCC28704
Other Parts Discussed in Thread: UCC28600

Tool/software:

Hello guys,

One of my customers is looking for a AC/DC converter IC for 10W class flyback topology converter.
They want to design AC/DC power supply as small as possible.
There target spec is the below.
Vin=85V~264V, Vo=12V, Power=about 10W.
They want to use the following transformer.
Wurth Elektronik
750370024
https://www.we-online.com/components/products/datasheet/750370024.pdf

My question is the below.

Q.
Can UCC28704 be used for a smaller AC/DC solution with this transformer?
(It is ok for them to use primary regulation topology though output voltage of this topology
is lower accuracy than second side regulation.)
Or if you have better device for them than UCC28704, please let me know?

Your reply would be much appreciated.

Best regards,
Kazuya.

1 month ago

0 Ning Tan 1 month ago

TI__Expert 8745 points

Kazuya san,

Please use the design calculator here to check if the transformer can support the design.

https://www.ti.com/tool/download/SLUC603

There is a transformer section in the calculator.

Best,

Ning

0 Ning Tan 1 month ago in reply to Ning Tan

TI__Expert 8745 points

I did a quick glance. The secondary and aux winding ratio is 1:1.33. Given Vout is 12V, the aux winding output will be ~16V, which is below the UVLO turn on voltage of UCC28704. So regardless of other parameters, this transformer is not going to work for UCC28704.

You can use UCC28600 for your application. UVLO is ~13V.

Ning

0 Kazuya Nakai59 1 month ago in reply to Ning Tan

Guru 21195 points

Hello Ning,

Thank you very much for your reply.

If the transformer secondary and aux winding ratio is 1:2.2~2.5, can it be used for UCC28704.

Thank you again and best regards,
Kazuya.

0 Hemanth Sreeperumbudur 1 month ago in reply to Kazuya Nakai59

TI__Intellectual 2370 points

Hi Kazuya,

Ning is out of office this week.

I see the UVOL (max) spec of UCC28704 as 23V. So it should work.

Abs max on VDD is 35V. Recommend to keep a OV protection clamp, that limits the voltage below 35V.

Regards
Hemanth

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UCC28704: Question about AC/DC converter IC for the inductor my customer selected.