EMC filter for TNYIII Design

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Hello, i did this tny flyback design (24V, 600mA) and the EMC filter is all after the diode bridge , not before it, like a normally see........do you know why this is?............it seems to me that if the common mode choke doesnt have much leakage then a lot of differetial mode noise will appear on the supply lines?

I think the cut-off for the software where it will start recommending an X capacitor is beyond about 20 W or so. The rationalle is based on experience than below 20 W if you have a decent sized pi filter the leakage inductance from the Cm choke will provice adequete differential mode filtering.
You can design for 24V, 0.9 A and see the configuration of the EMI filet will change to depict an X-capacitor filter.