Yes i guess so.
And do you agree, that we can only use a common mode choke in our common mode filter?...because we quite literally have nothing to connect Y capacitors to...so can't use common mode filter capacitors (Y caps)?
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Woops, I’ve just realised that if I make our negative return conductor our chassis ground, then this will mean that the chassis and frame of the drone will end up conducting current along with the negative return conductor.
Also, the downstream Brushless DC motors and inverters are likely to be using a chassis ground, which will likely be coupled to their power and return conductors via Y caps, as well as 1 Meg (say) resistors to stop chassis ground from getting induced up to a high voltage. Indeed the Inverters and BLDCs will need a chassis ground as they won't be able to connect their power return directly to chassis for the same reason that the chassis would end up conducting return current.
As such, we will need to have, would you agree(?), a separate chassis ground on the PCB, directly under the DCM module, and hence we will need to have Y capacitors connected to this -And use Common mode chokes aswell.
....Please confirm that if (say) we connected circuit negative return directly to the metal outer chassis of the power supply in one place only....that would still be a nightmare as the chassis would then basically act like an antenna, spitting EM noise out all over the place?
Do you agree that with our metal outer framed power supply, chassis ground and circuit return must really be separate? (ie not directly connected, but only connected with Y caps and high value resistors to stop chassis from getting induced up to high voltage?)
Also, ....on page 87 of the DCM design guide, it shows chassis ground in yellow. Chassis ground is deliberately not connected to any circuit ground (neither primary or secondary ground). This I believe is deliberate, because nobody wants their chassis becoming a circuit power rail conductor.
The yellow chassis ground pour is also shown directly under the noisy DCDC module, this is deliberate as it must “catch” noise escaping from the DCDC module and guide it back into the circuit conductors via the Y capacitors…would you agree?
DCM design guide: