LM5022: Transformer Pin Number

Sarumathi R

Part Number: LM5022

Hi Team,

I have found one reference design in TI webench which satisfies our power requirement.

https://webench.ti.com/power-designer/switching-regulator/export/55?noparams=0

Can you please tell me the transformer pin number details, i.e for which of the transformer pin the input and outputs are connected?

over 3 years ago

0 Youhao Xi over 3 years ago

TI__Guru 68495 points

Hi Sarumathi,

Thank you for considering our product in your application. The webench design referred by you is using two individual inductors, not a transformer. You can check the BOM generated by Webench, and you will find:

Lin is a Burns inductor, SDR1307-180ML. For detailed info please visit: https://www.bourns.com/pdfs/SDR1307.pdf

Lout is NIC inductor, NPI105C151MTRF. For detailed info please visit: https://www.niccomp.com/quickBUILDER/QBPN.php?pNumber=NPI105C151MTRF

Best Regards,

Youhao Xi, Applications Engineering

0 Sarumathi R over 3 years ago in reply to Youhao Xi

Intellectual 480 points

Hi Youhao,

I have checked the BOM also.

In that webench design,749196531(wurth transformer) is used. I have attached the design with BOM. You can check and confirm the same.Analog_Input_Power(iso).pdf

0 Sarumathi R over 3 years ago in reply to Sarumathi R

Intellectual 480 points

Hi Youhao,

Kindly help on this request.

0 Youhao Xi over 3 years ago in reply to Sarumathi R

TI__Guru 68495 points

Your previous link leads to a sepic design, this is why I got the wrong BOM info. Your updated circuit years Wurth transformer. Please check the Wurth website: Please visit Wurth website for the datasheet: www.we-online.com. Sorry currently I am away from my computer, and I am replying on my cell phone.

Thanks,

Youhao

0 Youhao Xi over 3 years ago in reply to Youhao Xi

TI__Guru 68495 points

Typo: ... uses Wurth transformers..., not yeses Wurth transformer. Sorry for the confusion.

0 Sarumathi R over 3 years ago in reply to Youhao Xi

Intellectual 480 points

Hi Youhao,

No issues.

I have a little bit confusion about the transformer connection. Because in that webench design(which i have sent earlier), they just connect the transformer with no pin number details.

can you please help on this?

0 Youhao Xi over 3 years ago in reply to Sarumathi R

TI__Guru 68495 points

Hi Sarumathi,

Okay, I see your question. I will ask our Webench team to add the pin numbers. It might be difficulty, though, because Webench picks up from the part library and different transformers may have different package or pin numbers, and it may just choose the transformer for function but not the pin out.

To close your issue here, I changed the transformer datasheet. It has the following pin out assignment. All the 6 windings have the same number of turns, namely N1=N2=N3=N4=N5=N6

According to the Webench schematic, the Np:Ns1=1:2, and Np:Ns2=1:1. Therefore, Ns1 has two windings in series (note the polarity). You can connect the windings according to the following diagram (sorry for the marking by mouse). Specifically, Np=N1//N2, Ns2=N3, and Ns1=N5 + N6

Thanks,

Youhao

0 Youhao Xi over 3 years ago in reply to Youhao Xi

TI__Guru 68495 points

The figures are corrupted. Let me reattach in a word doc below.

e2e reply.docx

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LM5022: Transformer Pin Number