LNK304 bypass overvoltage

Posted by: charysm on 11/26/2022

I am troubleshooting a power supply based on LNK304 in a sort of flyback configuration, unlike any of the typical circuits in the data sheet (please let me know if there are any such design notes etc).

I measure 15.3V across the bypass capacitor, with only the capacitor connected between the BP pin and S. Does that mean the LNK304 is damaged? I replaced a failed LNK304 and all other components (diodes, capacitors) seem to be ok when individually measured.

Thanks!

Comments

Hi charysm,

Thank you for using PI's LNK304.

In connection to your concern, may I ask for the following for us to further help you out?

Schematic
PCB Layout
Circuit/Power supply specifications

Thanks and regards,

Thank you for your response. In the meantime, I believe that a replacement part I used (in an originally working circuit) was faulty. I have solved the problem with a part from a different source, but if you can tell whether the attached image seems to show a genuine part or not, I could advise the vendor.

Attachment	Size
lnk304gn.jpg	13.15 KB

Hi charysm,

The attached image is a genuine part.

Thanks and regards,

PI-Lupin