We have all experienced Schrödinger's USB stick
Erm, all of mine seem to have something to identify 'top'
Intel has been showing off the next generation of USB connectors which will be the first to fit into ports whichever way up they are – thus avoid the Schrödinger's USB stick problem. The chip giant says the final specification will be locked down by July by the USB Implementers Forum, of which Intel is a member. In a …
I never realised the humble USB plug was a quantum computing device, but this revelation makes perfect sense. I am sure I have noted the orientation flipping on certain devices (top -> bottom transitions and vice-versa), but always attributed this to Murphy's Law (a.k.a. High Auditor Activity, as can be confirmed by the usual garden hose test). The two explanations are of course not mutually exclusive.
I always thought that usb cables were based in quantum mechanics, that is they have a spin 1/2
Like a strange quark, you put the cable in, turn it over, try again, turn it over and try again, then on the next half spin it fits.
Erm, all of mine seem to have something to identify 'top'
Yes, in the existing connector design, a patent design flaw that causes an obvious and common usability problem is "corrected" by imposing additional work on the user. That's a grand solution, and I'm glad Intel decided to stop there for 18 years so you could feel superior.
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Yes. Your current phone charger is also capable of delivering 100 watts.
It's a meaningless statement without a time component.
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We're talking power here, not work. My phone charger might be capable of delivering 100 Watt-Hours (in 10 hours), but it's not capable of delivering 100 Watt.
I think you probably twisted it around a bit.
Nevermind, it's Friday!
"I think you probably twisted it around a bit."
I think that twisting it around a bit could be dangerous too :)
Note: If it's reversible, then the ground will be on the centre connector(s) and the 20VDC will be on the outer connectors (or vice versa). For this type-C connector, that would give less than 2mm gap between ground and power, with some data connector strips between the power connectors.
" Yes. Your current phone charger is also capable of delivering 100 watts.
Bollocks it's meaningless… I'm yet to see a phone charger that can deliver 100 Joules in a second."
Yar... a fairly typical laptop charger delivers 70W (19 V @ 3.7 A) or less and it's a brick around 4" long and bigger than 1 x 1.5" in section. If you can pull that kind of power from a little 1" cube or smaller phone charger someone has worked another kind of quantum physics marvel.
Nope. To be honest, even 2A on a standard USB 2 plug seemed high to me. 5A on this frightens the shine off my shoes.
But: My guess is that (on insertion) GND makes contact first, then VCC and then data. The current is then only switched on when the plug is all in. I take it that there will be some really fast Schottky's involved for cutting the power if someone pulls the plug under load; 5A @ 20V DC pulls a longer spark than any gap possible in this small plug. I'd give it a lifetime of 2 cycles.
Flames, natch.
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Additionally, the voltage is 5V, not 20V.
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At the moment, yes. But the article stated that USB-C would support up to 20V/5A. And that is frightening when interrupted under load, especially as there will be some capacitors and coils in the supply to get the ripples of the SPS under control. The back EMF from that L/C combo can be much higher than the original voltage and make the spark longer.
It's not the insertion that I find dubious. it's when someone just pulls the plug, as it happen so often.
edit: I just looked at the presentation. The Micro-C type will be limited to 20V/3A. Still a lot.
quote: "The present USB standard limits the current draw to 100mA until the connection is confirmed through enumeration."
For USB 2.0 it also limits the maximum current to 500mA (5 steps of 100mA each), however I am sat looking at chargers supplied with phones that actually specify 1000mA or even 1500mA at 5V. IIRC if a hub device (charger) ties data to ground (or was it high?) some end devices will switch to "charge mode" and just try to draw as much current as possible.
Apparently consumers care more about getting their phone to charge quickly than not setting their domicile on fire, and manufacturers are more than happy to oblige :(
I am sat looking at chargers supplied with phones that actually specify 1000mA or even 1500mA at 5V
I guess then it's fortunate that these matters tend to be handled by appropriately qualified boffins instead of opinionated members of the general public. Who, upon further inquiry, might have discovered that (questionable assembly of some chargers notwithstanding) past 2007, the relevant part of literature for charging by USB in general is not so much ye olde USB 2.0 spec but rather something akin to the Battery Charging Specification, stating under section 3.5 ("Charging Current Limits"):
"The standard-A connectors defined in the USB 2.0 spec are rated for 1.5A. Since hosts, hubs and USB chargers all use standard-A connectors, the maximum current that can be drawn from any of these devices is 1.5A.
Thus, a dedicated charger is required to current limit at some current less than 1.5A, (or IDCHGR)"
...sorry, you were saying...?
quote: "The standard-A connectors defined in the USB 2.0 spec are rated for 1.5A. Since hosts, hubs and USB chargers all use standard-A connectors, the maximum current that can be drawn from any of these devices is 1.5A.
Thus, a dedicated charger is required to current limit at some current less than 1.5A, (or IDCHGR)"
That's fine for the Standard A end of the cable, but the other one is a Micro B that plugs into the phone. Hunting around shows 10W at 5V specified for Micro B in the power delivery, but also specifically mentions "PD aware" cables.
So I guess I am asking; Why would the PD spec mention 10W at 5V (which is 2A IIRC) when the standard A connector is apparently only rated to 1.5A, and how do you determine if a cable is "PD aware" to know that running 2A down it won't damage it?
quote: "I guess then it's fortunate that these matters tend to be handled by appropriately qualified boffins instead of opinionated members of the general public."
Qualified boffins are also members of the general public, and members of the general public can also be qualified. Admittedly my degree is not in Electrical and Electronic Engineering, but it is a related discipline, and I understand enough to refuse to accept "well they know better than you do" without any empirical data to back that up.
I've already learnt that USB power delivery specifications seem to be slightly at odds with each other today, I'm eager to see what else I can learn :)
5 amps through that hair's breadth piece of metal? What the flip kind of alloy are they going to use for that? Built in heatsink? Current USB implementations get warm at 500mA, let alone ten times that much. And you can't go ramping up the volts with pin separations a fraction under 1mm. Not in damp climates at least.
Many times I've tried to plug in a USB device only to find the plug won't go in. And the number of times I've had to take the monitor off the CPU thingy box to turn it on it's side or upside down so the plug will fit is now beyond a joke. The cables should come with instructions, preferably pictorial.