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LinkSwitch-TN2 not working properly in Buck configuration

Posted by: PratyushJayachandran on

We have designed a 5V buck based on DER-507(https://ac-dc.power.com/sites/default/files/PDFFiles/der507.pdf) using LNK3206D.
But the output is 64V as opposed to 5V.
Circuit diagram attached. The HV+ and HV- is from a 120uF capacitor on a 100W TOP259 Flyback supply. We used ES1J(600V, 1A, 35ns) for both the diodes.
We have already tried swapping out LNK3206D(with that from a different vendor) and replacing 1.2mH general purpose axial inductor with 2mH Ferrite core inductor. All cases behaving in the same manner.
LED D51 not populated.

Files
LNK3206_Buck.PDF (18.81 KB)

评论

Submitted by PratyushJayachandran on 10/16/2020

Never mind, it worked.

Submitted by PI-Lupin the Third on 10/17/2020

Hi PratyushJayachandran,

Apology for the late reply. Please let us know just in case you have further inquiries.

Thanks and Regards,

PI-Lupin the Third

Submitted by PratyushJayachandran on 11/21/2020

Is SC1099 equivalent to LNK3206?
My local PI representative told us that SC1099 can be used instead of this but on reading the datasheet I found that SC1099 doesn't have any reference for operation on buck mode.
Is there some other inexpensive Semi Custom part or other series that I can use for Universal to 5V, 300mA, transformer less buck convertor?

Submitted by PI-Chloe on 11/23/2020

Hi PratyushJayachandran

Good Day!

For input 85Vac - 265Vac and 5Vo with 300mA load Buck topology application, LNK3206 is suited for this application. I suggest that you use the standard Power Integration part.

You can register and use the Online PIExpert to compute for the design circuit values.
https://piexpertonline.power.com/site/login

Application note for LNK TN2 is AN70.

Thanks

Regards

PI-Chloe

Submitted by PratyushJayachandran on 12/01/2020

I have designed this buck convertor based on DER-507 for 5V.
The output voltage is close to 34V as opposed to 5V.
Circuit Diagram and PCB Attached.

Attachment 大小
Auxiliary.jpg (208.85 KB) 208.85 KB
Auxiliary_2.jpg (96.56 KB) 96.56 KB
Auxiliary_3.jpg (95.64 KB) 95.64 KB
Submitted by PI-Chloe on 12/03/2020

Hi PratyushJayachandran

Good Day!
Please help to provide the full requirement of the design.

Is the Vin DC or AC?
Minimum Vin
Maximum Vin
Output Voltage
Output Current

What is the value of the output inductor L11?
Please advise the manufacturer part number.

At what condition did you see the 34V output?

Thanks

Regards

PI-Chloe