Re: PD power start up
I believe we need a special start up state.
I'm confused by your statement. See comments below.
Yair Darshan wrote:
> It looks O.K. however I would like to make some changes in the wording of
> choice 1:
> Choice 1:
> Normal operation:
> The PD will will draw between 10mA to 350mA average current for
[Dieter] I don't like average. I believe 10 to 350ma are the limits that
trigger the TBD timers.
> During startup :
> The PSE will limit the current to 1.5 times the max. staedy
> state value for TBD msec.
[Dieter] I think you want more than this. Don't you want the PSE to guarantee
1.5 times Imax for about 100ms?
At present the PSE is only required to have a capacity of Imax available to
I can set the current to limit to 1.5 times Imax, but supply only Imax. Will
your PD start up?
> During startup, PD may drop the line voltage
> to zero for TBD mesec max.
[Dieter] This creates a conflict. Basic state machine has PD off for voltage <
The new state machine will need a timer to switch from start up to ON.
Plus some PD implementation issues. How does the PD maintain the start up
state with the input voltage equal to zero? Looks like you need some kind of
monopulser. This raises the issue of false triggering.
> Is it O.K. by you?
[Dieter] No. Your PD design is in violation of the detection state machine.
We need a new state machine to allow this method of operation.
> > -----Original Message-----
> > From: Dieter Knollman [SMTP:djhk@xxxxxxxxxxx]
> > Sent: ש, מרץ 24, 2001 8:21 PM
> > To: Yair Darshan
> > Cc: stds-802-3-pwrviamdi@xxxxxxxx
> > Subject: PD power start up
> > Yair,
> > I believe we have two choices.
> > Choice 1: Define a special start up case for the PD.
> > In this state the PD is allowed to violate steady state requirements.
> > The PD may drop the line voltage to zero.
> > The PD may draw any current level.
> > The PSE will supply current at a level about 1.5 times the steady
> > state
> > value.
> > The time for the start up state is limited to X ms.
> > Choice 2: The PD meets steady state requirements.
> > In order to receive power
> > the PD input voltage is >30 volts and
> > the PD current is >10ma and <350ma.
> > Some violations are allowed for Y ms.
> > Can we have a straw poll?
> > Dieter
> > << File: Card for Dieter Knollman >>