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Hi all, I believe we are on the right track with the updates represented in the ‘yseboodt_01_0518_backfeed_baseline’. The only concern I still have is with a “3-Pair PSE” trying to detect a single-signature PD (just for a single port system). I have the impression the (schottky) diode reverse leakage has not always been taken into account properly: either just neglected or represented as being a resistor (without additional current source in parallel). See my presentation in attachment. My concern is that a PD with real (schottky) diode bridges might become non-compliant to the 3bt standard and that a “3-Pair PSE” would be allowed not being able to detect a PDs with real (schottky) diode bridges anymore, due to hard to meet leakage current requirements. As such I do not have any problem with that, but do we really want to go that far? Next to my presentation, I also attached a spice schematic file for those that would like make simulations. FYI, the name “3-Pair PSE” is short for
“a 4-pair capable PSE providing power in 2-pair mode, whereby two pairs are connected to the positive VPSE, and one pair is connected to
the negative VPSE“. Best Regards, Joris Lemahieu Application Engineer ON Semiconductor +32 55 33 29 49 To unsubscribe from the STDS-802-3-4PPOE list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-4PPOE&A=1 |
Attachment:
Backfeed ad hoc - 3P detection.pdf
Description: Backfeed ad hoc - 3P detection.pdf
Attachment:
3P_detection.asc
Description: 3P_detection.asc