RE: UPAMD updated goals and unapproved minutes
Piotr,
Good comments.
There have been no votes on power yet and the main goals of the committee
have not been established by discussion and voting.
The messages written on page 7 are to generate comments and get folks
thinking about what will be needed and what will be possible. I rather
expect the message protocol will become a very active subcommittee as soon
as the main goals give them the problem that needs solving. Keep thinking
about it as it will most likely be needed. We need adapter->device,
device->adapter, device->device. It may also be considered as source->load
and load->source.
Now the much stickier political problem: 5V. There is the well established
USB standard that supplies 5V to the vast majority of devices at up to 2A,
ie 10W. Built on that base is the cell phone industry charging standard for
all cell phones and sub 10W devices established on a worldwide basis. The
MOU and specs are on the private pages for your review. A 12-14V low voltage
starting point is specifically there to avoid any sense of conflict with the
USB and USB derived power and charging schemes. The assumption is that we
wish to have that same universality at the 10-130W power range. USB for
<10W, UPAMD/1823 for >10W.
However, it is still the committees decision, through the balloting, what
voltages should be considered. You, and several other, may bring up the 5V
again if you wish, but consider the current conditions described above as
you do so. You could also make an argument for 7.5V or 10V.
The 12-48V range was also suggested on the reflector as being the largest
reasonably efficient voltage spread for adapters.
Having said that, it is reasonable to assume one of the first devices out
the door will be a small adapter with UPAMD input and a fully compliant USB
power output.
Our first efforts, starting with the next meeting will be to get the overall
goals debated, voted and accepted. Then we will have the criteria to
evaluate the options and the next goals for connector, communications and
power.
Bob
-----Original Message-----
From: Piotr Karocki [mailto:pkar@xxxxxxxx]
Sent: Sunday, July 11, 2010 1:22 AM
To: Bob Davis
Subject: RE: UPAMD updated goals and unapproved minutes
> Please check to make sure that your proposal(s) was included in some
manner.
> If it was not, I missed it, please try again.
I don't know if missing (maybe out-voted :) )
a) page 7, 9, 10; start-up voltage could be smaller, e.g. 5 V (only for
electronics), also amperage could be smaller (0.1 A, 5V/0.1A is 0.5 W,
enough to even big electronic); at least change goals to:
"Provide small nominal voltage (e.g. 12-14 V) at small max current (e.g.
<0.5A) until communications established"
b) page 7, messages:
"Supply power XX Volts YY mA max" --> "Could you supply power XX Volts YY mA
max"
"start powering me, for XX minutes, unless I communicate before that
timeout"
And, renegotation of power delivery could be clarified - should power
delivery be stopped by default, or by sending "STOP powering" message.
c) page 3, power range minimal - to power current USB devices (e.g. mobile
phones), 5 V max. 500 mA, so 2.5 W. Of course, if power supply could set 5
V, device could be charged even if supply cannot limit current to 500 mA :)
d) page 10; why minimum voltage 12 V? Many devices require 5 V=