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Yair, David and
Thong,
TI Engineering agrees to the
spec changes proposed by Yair.
Regards,
Steve
-----Original Message-----
From: Yair Darshan [mailto:YairD@xxxxxxxxxxxxxx] Sent: Monday, August 12, 2002 9:54 AM To: 'Dave Dwelley'; Thong Huynh (E-mail); Hemmah, Steve Cc: 'stds-802-3-pwrviamdi@xxxxxxxx' Subject: Max classification time for PD spec Guys,
We have specified min and max
classification time for the PSE spec.
It means that the PSE will
sense the current or voltage after 10ms from the time that the Voltage or
current to the PSE port and the whole function will be ended after total of
75ms.
The reason for 10ms min was to
allow the PD enough time to get stable.
Now we have to limit the max
stabilization time of the circuits at the PD to keep our 6db
margin.
So I suggest to define at the
PD spec at table 33-13 as follows:
Add item 7 to the table.
Parameter: "PD classification stability time " , Unit:"ms", value: 5ms
max.
Add note for item 7: "Measured from the time that classification voltage or
current applied to the PD port until the voltage or current reached to their 1%
of their steady state value"
Summary:
The classification
circuits at the PD will be stable within 5ms max.
The PSE will start
to take data after 10ms min. and will remove classification voltage/current
within 75ms max.
Please check (PD
chip vendors) if you can meet those numbers or suggest modifying
it.
Regards
Yair
Darshan Yair
Chief Engineer PowerDsine Ltd. - Powering Converged Networks 1 Hanagar St., P.O. Box 7220 Neve Ne'eman Industrial Zone Hod Hasharon 45421, Israel Tel: +972-9-775-5100, Cell: +972-54-893019 Fax: +972- 7755150-09 E-mail: <mailto:yaird@xxxxxxxxxxxxxx>. <http://www.powerdsine.com> |