LinkSwitch II electromagnetic susceptibility problem

Posted by: denyslk on 04/12/2016

Hi, we are using a Linkswitch II (LNK606DG) in our power supply, and all seems to be fine, except when we go to the electromagnetic susceptibility testing.

When the power supply is affected by an external magnetic field at frequencies around 134MHz, the power supply dies and even if the RF field is shut off after that, the power supply still doents recover and need a power shutdown and restart to make it work again.

we use an isolated flyback topology with a transformer having an AUX winding for regulation.

the output is 24VDC.

our circuit is based on the datasheet app note (datasheet page 4 circuit)

https://ac-dc.power.com/sites/default/files/product-docs/linkswitch-ii_family_datasheet.pdf

any suggestions?

Comments

I think its 12th harmonics of the main switching freuency which is about 65 - 66 KHz, now the question is how to protect the IC from being affected by this harmonics, and avoid IC shut down when the rf field is applied near the ic.

Hi, i want to design 12V/30W power, the schematic is already base on the reference. My problem is i don't how to choose the transformer.

kind please helf me.

Thanks,
Cuong

Hi,

Could you please send me your Schematic, PIXls design and PCB layout so that I can take a look at the design.

Regards,

PI-NANO

Hi,

The attachment is a reference schematic, How i can choose the switching transformer for this design?

What conditions are readly need for the switching transformer? can I choose transformer base on Power and Volatage out or other conditions?

Thanks,

Cuong

Attachment	Size
Schematic (92.37 KB)	92.37 KB

Hi cuongcdt2,

This is someone else's post.

Please post your question in a new post, so that things don't get mixed up.

Regards,

PI-NANO