I am designing a flyback converter that works at an operational frequency of 100kHz. Now, I need 2 levels of filtering at the input phase viz - common mode filter and differential mode filter. The common mode filtering is done using a common mode choke while the differential mode filtering is done using a pi filter composed of ferrite bead and capacitors. The current requirement is about 3Amps.
Now, my doubt pertains to the selection of these filters. For the common mode choke I went through the datasheets of different chokes that had decent impedance at the frequency of 100kHz. Likewise for ferrite beads.
But most of the said filters show impedance curves at frequencies greater than 1MHz. So, how can I select one for 100kHz ? Or is my thought process wrong ?