RE: Topologies and attendance
As far as I know, there are 4 manufacturers of notebooks that use an ID pin to notify the sink of the source's capabilities. HP's notebooks communicate both an active and a static report of the capability of the AC adapter;
a. A static ID reports the capability of the AC adapter. HP notebooks will not only judge the suitability of the AC adapter (and message to the user), but will also cause the notebook performance to conform to the power capability of the AC adapter. For most of HP's notebooks, metering of the power consumption is done inside the notebook (so the sink can modify its own power consumption).
b. The dynamic reporting (signaling when the AC adapter is outputting at some portion of its capabilities) is used in some of HP notebooks for power conformance or battery charge when standalone, and in all of the notebooks that have a docking station.
The methods of communication are simple analog signaling. They are effective and affordable and are used on the HP "Smart" Adapters. The Smart adapters range from 40watts to 230watts, and allow fluent use of the notebook lineup and re-use on small form-factor desktops and All-in-ones.
To meet my responsibility to disclosure of IP; HP has many patents related to both the signaling of AC adapter capabilities and methods of power conformance in the notebook. We are constantly exploring new approaches and implementations. My comments are technical only and in no way related to HP's value of these patents--Lee
-----Original Message-----
From: upamd@xxxxxxxx [mailto:upamd@xxxxxxxx] On Behalf Of Piotr Karocki
Sent: Friday, September 03, 2010 4:30 AM
To: upamd@xxxxxxxx
Subject: RE: Topologies and attendance
About (1) - so it is something like communication between power supply and power sink - could this communication model (layer 1 at least) be used in UPAMD?
From: upamd@xxxxxxxx [upamd@xxxxxxxx] On Behalf Of Atkinson, Lee [Lee.Atkinson@xxxxxx]
Sent: Friday, September 03, 2010 2:49 AM
To: upamd@xxxxxxxx
Subject: RE: Topologies and attendance
A couple of related usage models;
1. Notebooks with docking stations; the docking is a serial connection (the EPS is connected to dock, and then the dock provides power to the notebook). The docking station has its own power consumption which is variable, uncontrollable and not directly measurable by the notebook.
With HP notebooks, the AC adapter meters the actual output current and signals when the AC adapter is near its output capacity. The message is received by the notebook and the notebook reduces its power consumption.
2. Value in knowing the power source; Under-seat power on an airplane is 15.0vdc, identifying this source is valuable for 2 reasons;
a. HP recommends against charging the notebook on an airplane, and disables charge if we see a voltage that indicates such (as a safety precaution).
b. The power capability of the in-seat power is limited (to 75watts, I think). Unless the airplane is expected to adopt the UPAMD standard, then any adapter that would interface to the in-seat power should identify the source and communicate the capability of the source.
--Lee Atkinson, HP