High pitch noise from transformer in TNY290 construction
Posted by: JohanCh78
on
Hi.
I recently got a design for a automation project created with the online designer based on a TNY290. I have made a prototype based on this design, and it works great with the a stable voltage output as per the design. However, I have been trying to get rid of a high pitch noise from the transformer, that seems to come from the primary winding.
I tried using "Kontakt Chemie Plastik 70" on the primary winding, but this had some catastrophic failure in that the TNY290 chip actually exploded when powering up the board. :-)
I have to admit that my experience in winding transformers for high frequency applications is very low, so I'm looking for tips on how to improve this or other ways to supress this noise.
Best regards,
Johan Ch
Files
TNY290 schematic
(148.76 KB)
Hello Johan,
Good day and thank you for choosing Power Integrations.
To mitigate audible noise produced by the transformer, the usual solution we're doing is to deep varnish it. What we're using here in our lab for varnishing transformers is the Dolph BC346 or BC359. You can try using it as an alternative.
Another solution to reduce audible noise is to design the transformer to have a lower flux density (Bmax) on the PI Expert Online. Kindly refer to the attached image for full details about audible noise from the TinySwitch-4 design guide.
If you can share the full PI Expert file of your design, I will be happy to review it and give feedback on what can be improved further to help reduce the audible noise from the transformer.
Thank you and I wish you a great day ahead!
Best regards,
Tommy