USB powers up to the tune of 100W, new spec in the works

Julio Franco

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Staff member

Apple and Intel may be pushing Light Peak (aka Thunderbolt) technology forward as a true next-gen USB replacement, but that doesn't mean the latter will die so easily. The USB 3.0 Promoter Group is working on a new specification that will have USB 2.0 and 3.0 connections delivering up to 100 watts of power.

You may ask, how is this useful?

We could virtually power anything using a USB port. We already charge devices like smartphones and tablets using USB, and that's possible because the 4.5 watts delivered through current cables is sufficient. Now think about charging your laptop using USB, or more to the point, solely relying on USB connectivity to power your laptop at all times. Transmitting data simultaneously is part of the specification as well.

Key features of USB Power Delivery include:

  • Compatibillity with existing cables and connectors
  • Enables voltage and current values to be negotiated over the USB power pins
  • Enables higher voltage and current in order to deliver power up to 100W
  • Switchable source of power delivery without changing cable direction
  • Coexists with USB Battery Charging 1.2 and works equally well with both USB 2.0 and USB 3.0

A demonstration of the technology is expected by the end of the year, with a final revision of the specification to be delivered to the USB Implementers Forum (USB-IF) for publication and establishment sometime in 2012. As ExtremeTech likes to point out, just as Apple’s exclusive rights over Thunderbolt expire in spring 2012.

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Light peak and Thunderbolt? Is there no end to the relentless assault of cheesy version and product code names? I'm gonna need to start a spread sheet to keep track of all this Gulftown, Sandy Bridge, Froyo, Honeycomb, Gingerbread, Clarksdale, Haswell, Ice Cream Sandwich (?!).

What ever happened to good old fasioned 3.0.

Didn't Apple's last attempt at this fail miserably? Wasn't it called FireWire or something?
 
Next thing you see in the newspaper is people getting electrocuted by a USB cable ;)
 
This would be great for external hard drives. Think about all external hard drives having no power supply necessary. Yes I know there are a few usb power ones, but those usually are slow and don't work very well.
 
USB speakers (the quality kind) could also benefit on a similar fashion, a single cable for everything.
 
to win7dev's comment: yes, that would be great for full size drives, as well as full speed external burners. Another idea would be to power full size monitors (well, 19-21" monitors perhaps or perhaps piggyback two USB power connections). It'd be one less power cable and maybe video through USB as well.
 
Just was I was thinking. But perhaps the possibilities with powering everything through USB makes up for the additional cost of a 1000+ watt PSU.
 
Next thing in the market "KIDS DONT STICK YOUR FINGERS IN THIS USB" or maybe one that says "DANGER DONT GET CLOSE TO IT IF YOU OWN A PEACEMAKER"
 
Just was I was thinking. But perhaps the possibilities with powering everything through USB makes up for the additional cost of a 1000+ watt PSU.
And possibly the one after that....

All the people who think this a wonnnnnnnnnderful idea...where do you think all this extra power is being drawn from?
Hint: The southbridge slash I/O hub on the motherboard.

So, a few questions...
Bearing in mind that the standard fit-out for USB on a current board usually runs to 12-14 ports, what provisions are USB-IF making to prevent over-current draw?

Are all (any?) USB/mini-USB cables specced for continuous 8.3A/100w operation ?

At least I should see some more custom eventuating due to adventures in hot-plugging. As it stands, it doesn't take much for a sub-5w connection to take down an onboard controller.
 
Hey, I think this is great news. However, I've seen a number of computers with shorted out USB ports because of vandalistic children shoving coins, paper clips etc.. into the USB ports to purposefully damage them.

Imagine their surprise on one of these newer PCs...
 
Hey, I think this is great news. However, I've seen a number of computers with shorted out USB ports because of vandalistic children shoving coins, paper clips etc.. into the USB ports to purposefully damage them.

Imagine their surprise on one of these newer PCs...

On the plus side, they'll only do it once. Your next PC should be juvenile vandalism free!
 
I wasn't even crazy about my "UD7's 3xUSB power" feature. So to ask a dumb question...won't this overtax the PCB/Tracer design of the boards as well as the SB hub?
 
sure would kill laptop batteries - - and add a good load to OEM PSUs as well (so many are marginal)
 
I wasn't even crazy about my "UD7's 3xUSB power" feature. So to ask a dumb question...won't this overtax the PCB/Tracer design of the boards as well as the SB hub?
Yup. That's kind of where my thoughts were.
While not every USB port would be populated by a high amp/wattage connection, I would think even a minimal number would heat up a southbridge -even if it could accomodate the pass through.

Now, bear in mind that this is supposed to be compatible with standard USB2 and 3.0 how many average users are :
1. Going to aware of maximum current draw for the system, and
2. Owning a bog-standard PSU (as jobeard pointed out), or a capable PSU but connected to a board using a 4-pin 12v auxillary power connector.
3. Going to make the differentiation between standard and high current USB devices.

Cue a whole new forum hardware section

"Hi TS, first time poster. I have a problem with my computer. Every time I start it up- it shuts down. There's a big "Whump" sound from my speakers and thats it. Help"
 
I'm more interested in power over ethernet for cameras, printers, scanners, etc... Nothing worse for an IT guy than having to call an electrician to install an outlet for something.
 
Yup. That's kind of where my thoughts were.
While not every USB port would be populated by a high amp/wattage connection, I would think even a minimal number would heat up a southbridge -even if it could accomodate the pass through.

Now, bear in mind that this is supposed to be compatible with standard USB2 and 3.0 how many average users are :
1. Going to aware of maximum current draw for the system, and
2. Own a bog-standard PSU (as jobeard pointed out), or a capable PSU but connected to a board using a 4-pin 12v auxillary power connector.
3. Make the differentiation between standard and high current USB devices.

Cue a whole new forum hardware section

"Hi TS, first time poster. I have a problem with my computer. Every time I start it up- it shuts down. There's a big "Whump" sound from my speakers and that it. Help"

Thats what I think. Add to this that current USB cables can't possibly be up to the task of 8A/110w current, and the additional VRM/overvolt circuitry needed is going to add how much to the cost of the MB?
 
Everyone that is quoting 8A or so, have actually read the article? It pretty clearly states that higher voltages will be supported.

"Enables voltage and current values to be negotiated over the USB power pins
Enables higher voltage and current in order to deliver power up to 100W "

So potentially it could be upwards of 12 to 48 volts.

As far as the circuitry goes, leave that up to the engineers, as most of your guys are just trolling and have no idea.
 
@Guest 21

WTF are you on?
How many consumer computer peripherals are designed to run off 24 and 48 volts ?

While the spec more than likely calls for voltage negotiation- worst case scenario is 100w/5v = 20 Amps (!). At 12v (which would negate most consumer peripherals) 100w/12v = 8.3A (and 100w/24v = 4.2A, 100w/48v= 2.1A). So regardless of whether the source (mainboard) could supply the power, we're still left with the glaring fact that the USB-IF are saying that a standard USB cable is 20 Amp compliant....As with you post, I'll rate that "Whatever".

Current USB spec is 5v ± 5% output @ 500-900mA....that's 2.5 -4.5 watts just in case math isn't a strong suit.
 
Where are the USB-IF saying that a USB cable is or is going to be 20A capable?

And where did i say that a device was going to be 24 or 48 volts? The voltage can be boosted for transmission and bucked at the device to suit. That would be the only way for a two wire configuration. Since this wont be the case, the spec will most likely included mixed voltages and multiple cores for power.

Great work on using Ohms law, very impressive. Work out the size of cable that is required for 20A and the maximum length, max 5% volt drop, and the size of the connection. How practical would this be, not very. So rather than speculating and posting rubbish, just leave it to the pros kid.
 
And where did i say that a device was going to be 24 or 48 volts? The voltage can be boosted for transmission and bucked at the device to suit. That would be the only way for a two wire configuration. Since this wont be the case...
Quite the scientist...refuting your own argument. Sweet, saves time.
...the spec will most likely included mixed voltages and multiple cores for power.
Bearing in mind the 100 watt figure that the USB-IF have used, what "mixed voltages" were you expecting?* And using Ohm's Law, what resulting current are you likely to get?*

Now, getting away from current draw, most of the thrust of the discussion here-before it turned into the Guestroll-a-thon was centred around the 100 watt draw per port, and how it would impact on current motherboards, PSU's and systems as a whole since the USB-IF are touting "compatible with existing cables and connectors" (pdf)

* Not rhetorical.

Feel free to add your insights on where these multiples of 100 watts will be transmitted using existing consumer mainboards and I/O hubs....or carry on doing the troll thing and pick at an incidental facet of the discussion (already covered I believe in my previous post regards "voltage negotiation") while ignoring the matter at hand...whichever you feel more commensurate with your skill level...kid[/QUOTE]
 
It seems like some will just have to wait till the full spec is released to further better there understanding on this topic.
 
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