I'm perfectly happy if I'm wrong because that would mean that
I learn something, as long as we can explain why I'm wrong.
I am well aware that current is not "shoved" into a device that
doesn't "draw" (or "sink") that current.
I realize that the current "sourced" by the charger is whatever
the device "sinks", up to the maximum point that the charger is
able to "source".
However, what's "smart" about this charger is that it can "source"
2.4 Amps (or so it says) from each port up to a limit of 6.8 amps.
So, if you plug in three devices, two of which are tablets sinking
2.1 Amps, while the third is a phone sinking only 1.0 Amps, then
the device will "choose" which ports to source the 2.1 Amps and
which ports to source the 1.0 Amps.
I do understand you now in that you're saying that the device
"asks" (so to speak) for whatever amps "it" wants to sink, and
the charger just blindly supplies that (or it doesn't) when it's
an Apple charger.
What you're saying, I think, is that this charger just as blindly
does that too, but in the case of this charger, you don't have
to choose a low-power (1 Amp) port and a high power (2.4Amp) port
because the charger will choose which port to source the 2.4 Amps
and which ports to source the 1.0 Amps.
I'm not sure what the smart charger does when I plug in 3 tablets,
all "asking" to sink 2.4 Amps though.
There are two so-called 'superports'.
And they float to any two ports.
Why can't you see this?
You are right though, that the eoc isn't detected by the charger.
The sink current is detected, and that floats the two superports.
That's the smart part.
It doesn't detect EOC.
That's the dumb part.
The way I define it is that the charger is smart enough to
know how to shunt current to where it's needed without me
having to do that myself.
I plug in whatever I want to plug in (within the defined limits).
And the charger shunts the current to those devices accordingly.
If I plug in five devices which each "ask" to sink 1 amp of current,
then the charger is smart enough to make available a shunt of up to
1 amp each source current into those five sink devices.
Likewise, if I plug in three devices where one asks for 2.0 Amps, and
another asks for 1.6 amps and another device asks for 1.4 amps, then
the charger is smart enough to shunt 2.0 amps into one, 1.6amps into the
other, and 1.4 amps into the third, for a total of 5.0 Amps (or 25 Watts).
With many multi-port chargers, one port is a *dedicated* 2.1 Amp (max)
port while the other is a *dedicated* 1.0Amp (max) port.
This charger is "smart" in that the dedication is switched between
the ports (i.e., they're not all 2.4Amp ports, but any one or two
can be depending on what you plug into it).
But maybe I misunderstand since you people are telling me otherwise.
The 'reroute' power is the 'smart' part of the charger. Most USB
chargers only supply 1amp to the USB port. Some chargers supply 2.1
amps. However, supplying 2.1amps to 6 ports is a LOT of power, so most
chargers will designate one or two 2.1Amp ports.
This charger (and a lot of newer chargers) have some smarts that allow
them to route those two amps to whichever ports need them. In this case,
up to three ports.
This rerouting of which ports can provide 2amps has nothing to do with
the complicated software on the devices and batteries.
-- > I miss the old days. I haven't killed anyone in years.
I do understand that the "smarts" in the charger is simply for re-routing
the "superport" to up to three ports.
The "dumb" part of the charger is that it does not sense the EOC of
the battery. Those smarts are in the device/battery circuitry itself.
the smartness in that charger is for communicating with the laptop
about the adapter's capabilities, not charging strategies, which is
handled by the macbook based on the reported capabilities.
a magsafe charger tells the macbook its maximum power and the macbook
budgets it appropriately. if the adapter has less power than what was
originally supplied, the macbook will charge at a reduced rate or even
not at all, depending on how much power is actually available and what
the macbook needs.
in any event, the thread is about a usb charger which doesn't do any of
that. it outputs 5vdc, hopefully compliant with the usb charging spec
(some noname crap is not).
Yes, of course. We've all been using (relatively) dumb chargers for
years so it's pretty obvious that a wall-wart doesn't *need* to have
the smarts of a 128k Mac!
The point was being made (by Bruce Sinclair, to whom I was replying)
that modern chargers do have some smarts, and I thought it might be
interesting to give an example (as I'd just come across it recently and
had the link to hand) of a charger with a very great deal more smarts
than one might imagine.
It *is* slightly boggling just how smart a charger can be, while
remaining roughly plug-sized.
Indeed, but threads drift ... it would be a dull world if they didn't.
some do, but not for charging strategies.
the magsafe adapter example you cited is for magsafe communication so
that the laptop knows how much power is available.
for usb chargers, that's done over usb.
it doesn't communicate soc or eoc. that's in the device itself and/or
not really. there are much smaller products that are quite a bit
smarter than any charger.
Yep. If you don't know this, you work it out when you plug in a coiled cable
for a while and it gets hot. :)
Power cables on rolls have always come with the 'completely unroll before
using' (or similar) instructions. :)
it's better to not fail in the first place.
nothing is perfect, but buying a reputable brand which is known for
reliability is the best way to minimize how often you have to go back
to get something fixed.
In theory, that's true. What I recall of electronics brands reliabilities
however, is that there is actually little in it.
In theory, theory and practice are the same. In practice, they are not. :)
Personal experience with scientific equipment these days suggests that the
smarter something tries to be, the more often it will fail. MTBF I guess ...
the more bits, the more broken bits. :)
I am a class of '60 in EE. Started with vacuum tubes all the way to
in electronics engineering. MTBF has been improving steady over the
years. Just have a field trip to a big manufacturing plant and see how
QC engineers are screening components for their product. Very serious
affair. Even here you get what you pay for. For an example, mil-spec
laptops cost few times more than consumer grade. You figure out why!
Once back in '70s I witnessed testing mil-spec DEC PDP8 mini computer.
From chopper up 3500 ft. it was tossed down, it did not suffer damage.
Commercial grade PDP8 would be
in pieces scattered all over. Another example, look at Panasonic
Toughbook, ever tried one of those? You can run over it with your car
without any problem. I always try to buy prosumer level product when
I need something.
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