USB 3.0 SuperSpeed update to eliminate need for chargers

Tekkaraiden

TS Evangelist
A bit surprised it will offer 20v @ 5a but I suppose 3.3v + 5v + 12v = 20.3v.
Those voltages have a common ground not a floating ground, you can add them that way. Its the same as taking 2 steps forward or taking 10 steps forward. If you did one or the other you can't add the two.
It was more of a comment on the decision to have 20v as adding voltages in series does not increase the current.
 
G

Guest

This power requesting should work, but I have my doubts. On usb2 even I have a usb HD which *will* cause one pc I have to shut down, whenever its plugged in. Didnt fry anything, and on removal and rebooting everything was fine. Just wondering how marginal was that PS to cause that??
 

hahahanoobs

TS Evangelist
Ok, guys, this thing kept me awake till late, so I did some research, and here's the answer to all your questions...

When a USB device is connected it sends in a request to negotiate the power profile according to the needs of the device. The maximum supported by USB 3.0 is 4.5 watt (and not 10 watt).

The new USB spec simply moves the cap up to 100 watt as the maximum that a device can try to negotiate for (try is the keyword). Up until now no device could request for more than 4.5 watt from USB, such request would just fail.

This however imposes nothing extra on the USB, except not to send request-fail just because the device wants more than 4.5 watt. Instead, the request-fail will be guaranteed if a device wants more than 100 watt. But this doesn't mean that the new USB has to support more than 4.5 watt of energy. IT DOES NOT. The new USB must prove provide the output: 4.5 <= Output <= 100 watt.

To give it a good life example. Up till now when you are buying a device that provides USB 3.0 ports you didn't care about the maximum output on those ports, because they were supposed to provide 4.5 watt each, even if in practice that didn't always work, depending on the manufacturer and the controller. But now you will also be paying attention to the maximum output figure you can get from those USB ports, either separate or combined, so you can run it up against the devices you plan on marrying it with.

This does complicate things for the end user, as now one has to pay attention to the extra specification parameter, as each device with new USB ports will have its own cap somewhere between 4.5 and 100 watt, according to its spec.

I hope this clears things out.
Are you saying, based on your research, that if you plug a device into an updated USB 3.0 port, it could give it too much power, or cause damage to the port and/or device in some way?
 

Darth Shiv

TS Evangelist
Are you saying, based on your research, that if you plug a device into an updated USB 3.0 port, it could give it too much power, or cause damage to the port and/or device in some way?
No he didn't say that at all. Just that if you try to plug a 100W device into a hub that won't supply 100W, the hub says "no I can't supply that" and the device won't start.

Another implication is if you want up to 100W, there will be hubs out there that are supported by the spec that *can* give you your 100W.

He also said that if you plug in a device that wants > 100W, the spec says USB 3.0 is guaranteed to say "no you can't have > 100W".
 
  • Like
Reactions: VitalyT

hahahanoobs

TS Evangelist
No he didn't say that at all. Just that if you try to plug a 100W device into a hub that won't supply 100W, the hub says "no I can't supply that" and the device won't start.

Another implication is if you want up to 100W, there will be hubs out there that are supported by the spec that *can* give you your 100W.

He also said that if you plug in a device that wants > 100W, the spec says USB 3.0 is guaranteed to say "no you can't have > 100W".
To: Shiv and VitalyT
I think the below link is the opposite of what you two said. Correct me if I'm wrong please. I genuinely want to understand the new spec. I am not quite understanding your explanations.

engadget.com/2012/07/23/usb-100w-power-delivery-spec/

[SIZE=16px][FONT=Georgia]"Naturally, the new specification relies on beefier cables to deliver maximum juice, but we won't have to go replacing all our old wires -- it includes a means to check attached cables and devices and set the voltage and amperage accordingly. Perfect, that means we won't have to carry around bundle of proprietary power cords when we travel, and we get peace of mind that charging via USB won't have any, [/FONT][/SIZE][SIZE=16px][FONT=Georgia]ahem[/FONT][/SIZE][SIZE=16px][FONT=Georgia], unpleasant [/FONT][/SIZE][SIZE=16px][FONT=Georgia]side effects[/FONT][/SIZE][SIZE=16px][FONT=Georgia]."[/FONT][/SIZE]
 

VitalyT

Russ-Puss
To hahahanoobs: Are you trying to confuse here everybody? I condensed information as much as I could for people here to make sense out of it. But if you think this is not enough, then the following is for you:

1. Open the official USB 3.0 documents page: http://www.usb.org/developers/docs/
2. Click on the top link that says [SIZE=13px][FONT=arial]Universal Serial Bus Revision 3.0 Specification[/FONT][/SIZE], or, alternatively, the specification download link: http://www.usb.org/developers/docs/usb_30_spec_040313.zip

The archive is 23MB. Once downloaded, open document USB Power Delivery\USB_PD_V1_0+Errata Oct31.pdf, which is Universal Serial Bus
Power Delivery Specification (308 pages).

Either go through the contents table or jump to page 284, chapter Power Profiles.

Enjoy ;)
 
  • Like
Reactions: St1ckM4n

Darth Shiv

TS Evangelist
To: Shiv and VitalyT
I think the below link is the opposite of what you two said. Correct me if I'm wrong please. I genuinely want to understand the new spec. I am not quite understanding your explanations.

engadget.com/2012/07/23/usb-100w-power-delivery-spec/

[SIZE=16px][FONT=Georgia]"Naturally, the new specification relies on beefier cables to deliver maximum juice, but we won't have to go replacing all our old wires -- it includes a means to check attached cables and devices and set the voltage and amperage accordingly. Perfect, that means we won't have to carry around bundle of proprietary power cords when we travel, and we get peace of mind that charging via USB won't have any, [/FONT][/SIZE][SIZE=16px][FONT=Georgia]ahem[/FONT][/SIZE][SIZE=16px][FONT=Georgia], unpleasant [/FONT][/SIZE][SIZE=16px][FONT=Georgia]side effects[/FONT][/SIZE][SIZE=16px][FONT=Georgia]."[/FONT][/SIZE]
You are talking something a bit different there. Cables are a different issue entirely. Cables *do* have current ratings. 100W @ 20V = 5A. USB 2.0 delivered 5V and 0.5A by spec if I remember correctly. Out of spec hubs could supply 1A (for USB hard drives and so on).

So moving from 0.5A to 5A is a pretty hefty increase in current and the cables could get warm and potentially other related issues (maybe like causing the explosions you mention). As for the controllers themselves, they negotiate current limits.

If you want to use high current USB devices, buy good cables! :)
 

hahahanoobs

TS Evangelist
"If you want to use high current USB devices, buy good (high power) cables!
*fixed*

You just repeated what I said in my reply.
 

hahahanoobs

TS Evangelist
To hahahanoobs: Are you trying to confuse here everybody? I condensed information as much as I could for people here to make sense out of it. But if you think this is not enough, then the following is for you:
How can I personally confuse anyone? I posted exactly what Engadget wrote and it makes total sense. USB is not as complicated as you're making it seem... never was... never will be. I'll stick with Engadget on this one.

Assuming you're saying the same thing, using words like Hu, less than and greater than symbols, formulas and over-explaining (did I make a new word) a simple process, makes it very hard to understand for no reason.

It's USB, not a spaceship.