Conducted EMI fails with LNK304PN
Hello PI,
1. Can the design in AN37 Figure 1(b)pass conducted EMI test with output as -12V/120mA?
2. I have just verified a very similar design (just removing the rectifier diode Din2) but failed. The output is set as -12V/120mA. What is your proposal of low cost solution for passing the conducted EMI test?
Thank you in advance!
regards,
Michael
Comments
Hi Tucker,
Thank you for your quick reply!
Here I got another question. Can the conducted EMI be reduced by moving Din2 just beside Din1. Refer to the attachment please.
Thank you again!
regards,
Michael
That will not work.
The reason you need one diode in each leg is so that the whole circuit will "float" when the diodes are not conducting between AC cycle peaks. This is what reduces conducted EMI.
That is very helpful.
Din2 is there to reduce conducted EMI. The schematic in the Appnote is pretty much as low cost as it gets.