TNY280 Input coil calculations

Hi Raul,

Thank you for reaching out to us and using our products. I would like to suggest to keep your inquiries in 1 thread only since these are related to each other. But if you think, this is different from your previous questions then maybe you can create a new post.

Here's your previous inquiry that our engineer has initially responded on.

https://ac-dc.power.com/forum/pi-expert-support/2021/tny280-problems-calculations/

Thanks and regards,

PI-Lupin the Third

Hi PI-Lupin the Third

Thank you very much for your answer.

I thought that the input coil and the primary inductance of the transformer was a different thing and then wrote a different post.

There is a response about the inductance but still there is no
response about the input coil.

Please, tell me it is necessary write a new post or do something else.

Thanks.

Raul Diez.

Hi Raul,

If that's the case then let's keep this post. Your forum question has been delegated already and our engineer will reply here soon.

Thanks and regards,

PI-Lupin the Third

Hi Raul,
Thank you for your interest in PI Expert Online.
The selected L1 in your design is just a suggestion. There are no specific calculations that compose the value of L1 in the tool. The suggestion of L1 value is based on several bench testing. Unfortunately the tool has no ability to predict the exact EMI behavior on the bench, which can eventually pick an optimized value of L1.
Selection of an appropriate common-mode choke (CMC) requires a lot of EMI test iterations to get an optimized CMC value. What the PI Expert tool suggests is a good start value for the choke - but not necessarily the optimized one. With this, you can start using other L1 value and iterate which will be suitable for your design.

Hi PI-Quark

Thanks for your answer and regards.

Raul Diez