Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

RE: power delivery question from Liaison report



Title: RE: power delivery question from Liaison report

Just to be clear, we are almost certainly not putting a battery voltage directly on the RJ-45.
At the very least each ethernet UTP port to frame ground needs 2250 VDC of isolation, this is an existing spec.
When the working group talks about 48 VDC, we are talking about what the PSE (power sourcing equipment)
is putting out on the RJ-45, and it will need to be at least somewhat regulated.
We are now discussing what the voltage range needs to be.

If someone wants to regulate a 48V battery voltage to obtain the PSE output voltage, then fine.
If someone wants to regulate a 120V/240V, or 208, 3 phase line voltage to obtain the PSE output voltage, then that's also fine.

The working group will not be involved in that decision; that it outside the scope of IEEE802.3af.
IEEE802.3af will only spec the output V, I  of the PSE, not the input power.

Also, the Liaison report was talking about restrictions beyond SELV.
Some (many?) of us would desire the absolute maximum voltage to be above 48 VDC, like maybe 52 to 56 VDC,
otherwise we will have to limit the available power.

- Rick