Re: [802.3_4PPOE] Backfeed presentation + baseline

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Hi all,

Agree. We also suggest the 3P-backfeed PD to be at least 21V to safeguard the classification, while 30V is better.

Many thanks to editors’ effort and work.

Best Regards,

Yan

From: Stewart, Heath [mailto:Heath.Stewart@xxxxxxxxxx]
Sent: Friday, May 11, 2018 8:50 AM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] Backfeed presentation + baseline

Lennart,

As always we appreciate your ongoing work. We continue to have some concerns regarding the PSE requirements. As written they do are in effect during 4-pair power operation (and at all other times, without limit.)

We consider a PD which presents a reflected voltage (above Vrefl) during classification to be undesirable. As such we have marked up your presentation to suggest some changes.

Cheers,

-Heath

From: Lennart Yseboodt [mailto:lennart.yseboodt@xxxxxxxxxxx]
Sent: Thursday, May 10, 2018 10:15 AM
To: lennart.yseboodt@xxxxxxxxxxx; Stewart, Heath <Heath.Stewart@xxxxxxxxxx>; STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] Backfeed presentation + baseline

Hi Heath,

v220 and v230 correspond to both approaches we discussed during the adhoc call.

At the end of the call, I believe the consensus was to split Irev into two values (for >21V and <21V), which corresponds with v230.

Overview:

v220

- PSE requirement Irev is 1.3mA and applies when applying 2-pair (=3-pair) power on the unpowered negative

- PD has to safeguard classification, hence has a 3P-backfeed requirement from 0-21V

v230

- PSE requirement is split into 500uA when highest pairset voltage <21V and 1.3mA when highest pairset voltage >21V

- Because the PSE has a current limit that does not corrupt classifcation in the classification range, the PD is only required to limit 3P-backfeed in the detection range 0-10.1V

The advantage of v230 is that it allows for wider implementation of PD bridges.

Kind regards,

Lennart

On Thu, 2018-05-10 at 16:05 +0000, Stewart, Heath wrote:

Lennart,

Version 220 showed 21V. This version shows 10.1V. Can you comment?

Heath Stewart
Design Center Manager

PoE/PoDL Products

Cell      (805) 895-0499
Office   (805) 560-7658
Websites   analog.com, linear.com

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From: Lennart Yseboodt [mailto:lennart.yseboodt@xxxxxxxxxxx]
Sent: Wednesday, May 9, 2018 12:49 PM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] Backfeed presentation + baseline

Updated as discussed during the meeting, this is version 230.

On Mon, 2018-05-07 at 20:40 +0000, Lennart Yseboodt wrote:

Hi all,

As presented today. I’m currently updating the text based on the feedback I got.

Kind regards,

Lennart

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