LM5026: schematic and transformer claculate

Tommy Tzeng

Part Number: LM5026
Other Parts Discussed in Thread: PMP11478, , UCC2897A

Hi Sir,

could help check this schematic is correct? or any suggestion to us, thanks for you support and from you learn.

in addition, how do we calculate the turn ratio and parameters of flyback T2? because can't find tool that webench can simulation on website.

we specification is vin range= 24v~57v, Vout= 57v/2.5A.

IPGS-2504ATO-LM5026MT-20231124.pdf

10 months ago

0 Hong Huang 10 months ago

TI__Guru 54055 points

Hi,

This will take about a week. I will reply to you then.

0 Tommy Tzeng 10 months ago in reply to Hong Huang

Genius 5085 points

Hi Hong Huang,

in addition, about the Power Transformer(PA6296-AL ), we can not find specification on website, can sure this is Coilcraft?

0 Hong Huang 10 months ago in reply to Tommy Tzeng

TI__Guru 54055 points

Hi,

Not sure your transformer question - is it your design? Where did you get this part number? I am not sure how to answer this as I do not know where you found this transformer.

0 Hong Huang 10 months ago in reply to Hong Huang

TI__Guru 54055 points

Hi,

It looks you copied the design PMP11478

PMP11478 reference design | TI.com

It is a tested design. So it looks no need to have a review from me.

0 Tommy Tzeng 10 months ago in reply to Hong Huang

Genius 5085 points

Hi Hong Huang,

so is our schematic great? no any comment?

0 Hong Huang 10 months ago in reply to Tommy Tzeng

TI__Guru 54055 points

Hi,

No, the design you copied is a tested design on LM5026 so it is good unless you have questions. On none LM5026 related I am not familiar so you need to ask an expert in that regarding for review.

0 Tommy Tzeng 10 months ago in reply to Hong Huang

Genius 5085 points

Hi Hong Huang,

The customer schematic is PMP11478.

so we want to know if there is wrong with this schematic?

0 Hong Huang 10 months ago in reply to Tommy Tzeng

TI__Guru 54055 points

Hi,

You need to contact Coilcraft to check. The part number is a Coilcraft part number. The part is not a release so you cannot find it by searching.

0 Tommy Tzeng 10 months ago in reply to Hong Huang

Genius 5085 points

Hi Hong Hunang,

yes, already contact Coilcraft and the datasheet has been received, thanks for your help.

as attached below, but we also want to know if this schematic is correct? or any comment.

IPGS-2504ATO-LM5026MT-20231124 (1).pdf

0 Hong Huang 10 months ago in reply to Tommy Tzeng

TI__Guru 54055 points

Hi,

I have replied this is a tested design so I have no other comment to unless you have other concerns.

0 Hong Huang 10 months ago in reply to Hong Huang

TI__Guru 54055 points

Hi,

It looks your specs are different from PMP11478 which has 12V output but yours has 56V output. The transformer from PMP11478 cannot be used in your design. You need to redesign your transformer. So simple copy-and-paste from PMP11478 cannot meet your specs.

The schematics are ok but you need to re-design each component based on your specs.

LM5026 does not have a proper application note. A similar one is for UCC2897A which is very similar to LM5026.

https://www.ti.com/lit/pdf/slua535

Actually you may want to change to UCC2897A as it has been a main controller to work with PoE. But it is ok you want to keep using LM5026. The procedures including transformer design can be found in the above applicaiotn note.

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LM5026: schematic and transformer claculate