RE: UPAMD updated goals
Mark,
After the power reduction to .7w was suggested is also meets another issue
that will need to be addressed. As the UPAMD will be used everywhere in
changing conditions, safety issues like spark generation capability will
need to be considered. This standard connection will be used in areas where
natural gas, Liquid Propane, or other flammable gas, may be leaking or in
places where gasoline(petrol) fumes may be present such as in a vehicle or
service(gas) station or garage. Using the existing standards, such as
s60601-1, under 17V, with a dependency on the capacitance on the line, and
less than 55ma, depending on the inductance of the cables, defines the safe
area. So 12-14V at 50ma max is a good starting point as long as the source
capacitance is lower than 0.05uf and the inductance is less than 5 mH.
Bob
-----Original Message-----
From: upamd@xxxxxxxx [mailto:upamd@xxxxxxxx] On Behalf Of Mark Anderson
Sent: Thursday, July 29, 2010 9:31 AM
To: s.colclough@xxxxxxxxxxx
Cc: UPAMD
Subject: Re: UPAMD updated goals
The only purpose of this power is to allow non-battery powered devices
to ask the adapter for more power. For this purpose 700mW is probably
still on the high side, but it's really a back of the envelope number.
Once we've decided on how we're going to communicate, picking a
minimum will be easier.
We don't want to encourage use of communication-less power in the
10-130 watt area. For stuff <10 watts, I think the consensus is to
let microUSB handle it.
<snip>
> e. Adapter<->Mobile Device communications required for higher power safety
>>0.7W (down from 7W ie 12-14v@50ma) I support this concept, but why so low
a
> value? This will add unnecessary cost to the cheapest end of the market.
> Is there a problem with something like a 5W adapter supplying power all
the
> time? If a product needs to control power going into it, then the product
> probably already does it. For example, anything with LiIon batteries has
to
> control the charge current to the cells (as per IEEE 1625 or IEEE 1725).
> Why add another layer of communications for low power devices? Sorry I
was
> not at the meeting to have heard the discussion on this change.
<snip>