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

Re: [STDS-802-3-MAINT] [v120] Re: 802.3cq - inrush baseline v110



Lennart – the second paragraph has a defect.  Not sure which one I prefer yet.

The PSE either uses the legacy power up method, whereby it limits the inrush current to IInrush until the PD input voltage

reaches 99% of steady state, or it limits the inrush current for a fixed amount of time, TInrush, as defined in Table 33–11.

See ‘legacy powerup’ in 33.2.4.4”

 

It limits the inrush current TO WHAT for a fixed amount of time, TInrush.

 

I think you mean

“The PSE either uses the legacy power up method, whereby it limits the inrush current to IInrush until the PD input voltage

reaches 99% of steady state, or it limits the inrush current to IInrush for a fixed amount of time, TInrush, as defined in Table 33–11.

See ‘legacy powerup’ in 33.2.4.4”

 

Also, I’d probably reword it to be clearer about legacy power up: (and aren’t these both requirements – if show, change “limits” to “shall limit” – if not, they must be covered by a general shall on the table?)

 

“If using the legacy power up method (see 33.2.4.4), the PSE limits the inrush current to IInrush until the PD input voltage reaches 99% of steady state.

When not using the legacy power up method the PSE limits the inrush current to IInrush for a fixed amount of time, TInrush, as defined in Table 33–11.”

 

This last one is my preference.

 

Thanks for winnowing it down to something clear.

 

-george

 

From: Lennart Yseboodt <00000b30a2081bcd-dmarc-request@xxxxxxxx>
Sent: Thursday, November 01, 2018 1:45 PM
To: STDS-802-3-MAINT@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-3-MAINT] [v120] Re: 802.3cq - inrush baseline v110

 

Hi all,

 

Please find a new version of the baseline.

It was brought to my attention that our new inrush rules actually relax the inrush requirement in a particular case.

When a PSE assigns Class 4, per the current text and state diagram, the PD must obey a Class 3 power limit until Tdelay.

 

Our new section relaxes that to drawing less than 400mA. Ultimately we need both of these requirements.

 

The new version v120 adds a new requirement (last sentence) to address this.

I've also added the original subclause for reference.

 

Kind regards,

 

Lennart

 

On Tue, 2018-10-23 at 22:47 +0200, Lennart Yseboodt wrote:

Hi all,

 

Attached updated text for the PD inrush section as discussed on the last adhoc.

I put in two variants for the informative piece of text describing PSE inrush behavior. At the next adhoc call let's pick one of these.

 

Kind regards,

 

Lennart


To unsubscribe from the STDS-802-3-MAINT list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-MAINT&A=1


To unsubscribe from the STDS-802-3-MAINT list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-MAINT&A=1