Mark, I think the reason that printers don't ship with USB cables is
because it gives retailers a chance to sell them for $20 each...
For as long as I can see, the OEM will need to provide an AC adapter
with the product.
- Especially for a notebook, the size of the AC adapter must be mated to
the performance capabilities. Yes, we allow a 65watt adapter to be used with a
120watt notebook, but the old adapter is not going to supply full performance.
And in reverse, nobody wants to carry a 120watt adapter with their mini-note.
- I'm not sure that anybody is going to solve the problem of
EMI compliance with untested combinations. Even when the source of these is
within our control, we still have to match and test combinations of AC adapter
suppliers and end product.
We're a long ways from a worldwide mandate on common adapters, even
within a narrow segment of product (say, just notebooks) there is significant
difference of opinion as to whether such a standard should be mandated. For the
standard to really be effective and get broad adoption will face very serious
review. My marketing's view is that our simple 3 pin analog method was just
engineering run amok, no matter that we can all point to specific benefits for
customer and our supply chain---Lee
-----Original Message-----
From:
Mark Anderson [mailto:emer@xxxxxxxx]
Sent: Monday, December 13, 2010 3:06 PM
To: Atkinson, Lee
Cc: Edgar
Brown; upamd-comms@xxxxxxxx; garrytomlins@xxxxxx; Piotr Karocki; upamd@xxxxxxxx;
Leonard Tsai
Subject: Re: Simple analog signaling for an AC
adapter
I think the big win is going to come
when you no longer have to ship
adapters, much like printers no longer
ship with USB cables.
I am 100% behind cost savings. I
am not however, for watering down
the standard. I think adding a
resistor will cause no one to use
active messaging, and I think all
devices should be.
Mark
On Mon, Dec 13, 2010 at 3:30 PM,
Atkinson, Lee <Lee.Atkinson@xxxxxx> wrote:
> Edgar, in fact the only guy I know
using a digital communication method for
> ID is Dell. To Gary V's question,
have we rationalized the messages that we
> want to send to the sink, with
expected latency ? Have we also confirmed
> what kinds of devices would use
active messaging?
>
> My thinking on a few
topics;
> a. There is no A/D or
microprocessor needed for a simple proportional
> signal. Though A/D and processors
are common in notebooks, simpler devices
> could use as little as a
transistor and resistor (if they need to discern
> the power capability of the AC
adapter at all).
>
> b. The only negotiation for power
is simply to declare a connected load; we
> are on the path of a single
terminal voltage and not a sink programmable
> voltage (as was contemplated at
first and would have required the more
> complex signaling).
> Spark Free does not
need the ID pin, certainly our Cupertino friends vary
> to terminal voltage as a function
of VCC load (the spark in this case is
> particularly interesting, since
they are the only notebook company I know
> that positions its output voltage
when connected).
>
> c. If the communications protocol
needs to announce the power capability of
> the AC adapter, it can do so in a
number of ways (by either static or
> dynamic signaling, via either the
ID pin or the VCC mains). We don't really
> even need an ID pin to confirm
basic power capabilities.
> One area that
has not been confirmed is the need to build UPAMD around
> infinite gradients of power
capability; I agree that a static analog ID is
> going to have problems
discriminating a 53watt adapter from a 54watt
> adapter. But if we believe that a
finite set of power capabilities (eg, 20w,
> 40w, 65w, 90w, 130w) then an
analog method will be sufficient (we only need
> the equivalent of a 3 or 4 bits of
data).
> HP Smart actually
becomes digital (low impedance to VCC) at the power
> limit, so an arbitrary power
capability can be messaged. If we want
> messaging of a change in power
capabilities we could achieve this
> dynamically thru the same analog
signal.
>
> d. There is nothing to prevent
digital communication on the same path as an
> analog descriptor. A pullup is a
pretty benign thing on a digital path.
>
> I laughed out loud when I saw
Garry's mail (that 'a resistor and a wire are
> a big deal'). I think Garry
has been spying on emails with my marketing,
> who have perpetually questioned
any value towards even our 10 cent solution
> in HP Smart. To a degree, I cannot
argue with my marketing's argument
> against a "scale of dis-economy;"
meaning, volume never erases the cost of
> real material. I am not HP's AC
adapter purchasing or development engineer,
> but I can tell you exactly how
many cents we pay for the connector and wire.
> I can tell you as well the
increased failure rate in the field by just 1
> added wire on the connector.
Pretty much the world except for Dell and HP
> don't deploy any kind of ID.
Volume cannot erase real costs for copper,
> epoxy and silicon.
>
> The truth is that
unless I can prove to my own marketing that we've
> enabled a really compelling
feature for the AC adapter, I will be unable to
> get their support for the UPAMD
effort. What can we do to make a convincing
> story that we've been sensitive to
the value requirements of mainstream
> consumer products ?
Lee
>
>
> -----Original
Message-----
> Sent: Monday, December 13, 2010
12:03 AM
> To:
upamd-comms@xxxxxxxx
> Cc: garrytomlins@xxxxxx; Piotr
Karocki; upamd@xxxxxxxx; Leonard Tsai
> Subject: Re: Simple analog
signaling for an AC adapter
>
> As an analog and mixed-mode
designer I learned quite some time ago that it
> is preferable not to use an analog
system when a digital one can do a better
> job. Tolerances, repertoire of
possible responses, long time constants, and
> safety are all rather easy to
handle and expand through digital means, but
> can become very complicated and
costly through analog ones. My fears in
> allowing for a completely analog
'communications' system to coexist with a
> digital one would be:
>
> (1) we compromise overall
safety
> (2) we make it harder to satisfy
the stated goals (e.g., life expectancy of
> standard, adapter/device
compatibility over life of standard, and
> certification
support)
> (3) we could be hindering standard
adoption rather than promoting it.
> (4) we might have to create a full
digital communications standard from
> scratch (thus increasing overall
cost)
> (5) we would be increasing the
cost of adapters and devices that wish to
> implement the digital parts of the
standard.
> (6) we could be limiting what can
be accomplished by the digital
> communication system (e.g., speed,
compatibility)
>
> We have to keep in mind the point
that Leonard and Piotr have made, once
> devices and adapters are being
produced in quantity, the differential cost
> between an analog method and a
digital one will mostly disappear. At that
> point, all adapters and devices
will have to keep around analog
> communications subsystems just to
remain compatible, with no real added
> benefit.
>
> I would expect the cost curve to
follow the same adoption path as many other
> technologies (1) first the
high-cost high-margin devices will adopt the
> standard (for which functionality
would be key), (2) added-value multi-port
> adapters will follow suit, (3)
both of these will create a market for ICs
> and off-the shelf subsystems for
UPAMD thus reducing implementation costs,
> (4) lower cost devices and
adapters will start adopting the standard. I
> would expect such adoption curve
to be followed with or without analog
> communications, and I actually see
that requiring analog communications as
> part of the standard could hinder
rather than accelerate adoption.
>
> Although I can see how a purely
analog system can work, I cannot see how it
> can easily satisfy goal 5 (higher
power applied only when it is safe to do
> so); goal 4, as the aging of
analog components will make it harder to
> guarantee safety or compliance for
the life of the adapter; or goal 6, as
> the certification of analog
systems across age and component variations
> would become harder to accomplish.
(An example that comes to mind is the
> UCD9248 IC from TI, as it states
in its errata that it cannot reliably
> identify a considerable section of
its address range because it relies on
> resistors and analog values to set
it.)
>
> Gary and/or Arjan, can you come up
with a more fleshed-out proposal on
> alternatives for how this analog
communications would work? A reference
> design would be ideal, but at the
very least it should attempt to address
> safety and digital communications
compatibility.
>
> For the sake of argument, if we
assume that digital communications would be
> following a differential CAN
standard over a separate pair, what
> modifications would be required to
make analog communications work?
>
> We can discuss on this Tuesday's
communications subgroup meeting.
>
> Edgar
>
>
> On Dec 8, 2010, at 8:00 PM,
<Leonard_Tsai@xxxxxxxxxx>
> <Leonard_Tsai@xxxxxxxxxx>
wrote:
>
>> Coming from ODM point of view,
the digital communication cost will
>> disappear
>> fast than you expect. Most of
the power adapter today already include
>> digitally control IC. Adding
an interface of digital communication channel
>> may increase small $ in the
beginning but will disappear once healthy
>> competition
starts.
>>
>> Analog way is a bigger problem
as it creates testing requirement for
>> production line and room for
error.
>>
>> Leonard
>>
>> -----Original
Message-----
>> Sent: Wednesday, December 08,
2010 8:20 PM
>> To: Piotr Karocki;
upamd@xxxxxxxx
>> Subject: RE: Simple analog
signaling for an AC adapter
>>
>> I agree with Lee and
Arjan:
>> This is heading down a path of
unnecessary and complex functionality that
>> leads in turn to a complex and
expensive implementation. I beleive it will
>> not be attractive to the major
equipment ODM's who will need to adopt this
>> if
>> it is to be a
success.
>> We should have a simple analog
low cost option.
>> In my experience in servicing
the adapter market for high volume
>> electronics
>> adding a pin, a wire, a
resistor a pin to an IC is a big deal - let alone
>> a
>> separate communications
system!
>> My vote is for a simple analog
option as described. I believe this will
>> have
>> a good chance of adoption and
would be a success for the project.
>> Garry
>>
>>
>>
>> Texas Instruments (Cork)
Limited, Registered in Ireland under Registration
>> Number: 294554, Registered
Office: Riverside One, Sir John Rogerson's
>> Quay,
>> Dublin 2
>>
>> -----Original
Message-----
>>
>> Sent: 08 December 2010
11:50
>> To:
upamd@xxxxxxxx
>> Subject: Re: Simple analog
signaling for an AC adapter
>>
>> I don't agree with
Arjan.
>>
>> We could either "describe
current situation" or "shape the future".
>>
>> Our standard could allow
resistor-based "communication", something,
>> something, and full
communication (required voltage etc.).
>> But as one of goals is to
allow to connect every device to every supply
>> (and,
>> in near future, connections in
form of grid; power hubs, power storage
>> etc.),
>> every supply has to have full
communication option. Making provision to
>> understand simpler
communication (as resistor based) makes supply more
>> costly.
>> Say, we have hundred million
devices. Half of them - resistor based
>> communication, and tenth of
them - full model of communication (4/10 of
>> them
>> some 'in-between'
form).
>> Or, we could force whole 100
000 000 devices to have full model of
>> communication.
>>
>> But it is the only way to make
this full communication cheaper - as it
>> would
>> be "more mass" production. It
would be ONE standard...
>> And the only way to make
possible to connect device from 2010 to power
>> supply
>> from 2050 or vice versa. This
scenario is not impossible - when standard
>> becomes "grid version"... How
often you change wiring in your house?
>>
>>
________________________________
>> From: upamd@xxxxxxxx
[upamd@xxxxxxxx] On Behalf Of arjan strijker
>>
[arjan.strijker@xxxxxxx]
>> Sent: Wednesday, December 08,
2010 12:26 PM
>> To: Atkinson, Lee; Bob Davis;
upamd@xxxxxxxx
>> Subject: RE: Simple analog
signaling for an AC adapter
>>
>> I agree with Lee that UPAMD
should also support low cost devices.
>> A simple resistor to ground
inside the device could tell the adapter what
>> voltage it
requires.
>> More sophisticated device can
still do power negotiation etc.
>>
>> With regards,
>> Arjan Strijker
>>
>> Sent: Wednesday, December 08,
2010 12:08 AM
>> To: Bob Davis;
upamd@xxxxxxxx
>> Subject: Simple analog
signaling for an AC adapter
>>
>> Bob, here is
a quick presentation on the method that HP uses for
>> signaling from the adapter to
the notebook. We've had this system in place
>> since 2005 or 2006, and have
shipped maybe close to 150million systems
>> that
>> use the common "HP Smart"
system (including notebooks, all in one
>> desktops,
>> and small form-factor
desktops).
>>
>> My
suggestion is that we at least baseline a system that will allow
>> some
>> scalability of the
communication method; at least, allow very low cost
>> devices to connect to a UPAMD
power source and work reliably even if their
>> functionality is limited. I'm
not sure that a lot of simple devices that
>> would use UPAMD have a need
for all the messages that the adapter could
>> provide, or would be able to
negotiate variable power consumption. I think
>> we
>> all agree, there is very
little precedence for using sophisticated
>> signaling
>> in the common DC powered
devices now in the market. Though I agree the
>> simple
>> methods are limited, if we can
deliver a scalable solution there will be
>> fewer reasons for the industry
to not adopt UPAMD.
>>
>> Thanks again--Lee
>>
>>
===============================================================================================================
>> This message may contain
information which is private, privileged or
>> confidential of Compal
Electronics, Inc.
>> If you are not the intended
recipient of this message, please notify the
>> sender and destroy/delete the
message.
>> Any review, retransmission,
dissemination or other use of, or taking of
>> any action in reliance upon
this information,
>> by persons or entities other
than the intended recipient is prohibited.
>>
>>
===============================================================================================================
>