EMC question this day… when I have a circuit with some conducted noise on the supply line (maybe from a switcher, fast logic and so on) usually the solution is a common mode choke. One line for the ground, the other for the supply.
However, what about two or more supply lines with a common ground return? The current is not balanced anymore between a supply and the ground. Also being unbalanced the current compensation of the choke is not so effective anymore.
What is the correct solution in this case? given that's a DC supply and not a differential data line (i.e. no care for the differential signal content) I was thinking about a more traditional balanced LCL filter like the one typically used for harmonic suppression in RF:
Inductors would be rated for resonant frequency and saturation current but should work.
Is there a better solution? There are multiple (three or four) winding filter but they are quite rare and usually small (I think they are designed for audio)