USB 3.0 power to USB 2.0 device?

Discussion in 'General Hardware' started by jeffason, Nov 20, 2012.

  1. jeffason

    jeffason Member

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    Hello all,

    I leverage my Android smartphone's USB tethering support for internet sharing frequently and I am finding that the 500ma power output from USB 2.0 is not sufficient to maintain a charge over long periods of time with heavy use. I did some research and found USB 3.0 outputs 900ma which I think should be enough to maintain a charge while tethering under these conditions.

    If I were to purchase a USB 3.0 PCI-E expansion card for my desktop would I be able to send the USB 3.0 power output to a USB 2.0 device? Does it depend on the driver manufacturer? I noticed in the Windows "USB Root Hub" properties there are sections pertaining to power (not sure how to control it, though).

    I actually did purchase a USB 3.0 PCI-E card to try it out but I'm having issues with it even working properly for my USB 2.0 device. I also noticed that the associated "VIA USB 3.0 Root Hub" device in my device manager did not have the same power options as the Windows USB 2.0 drivers do.

    I also thought that maybe there is an adapter I could get and plug 2x USB 2.0 ports into then from the adapter go to my phone to provide additional power?

    Is any of this possible? Do you have any recommendations or success stories for trying to do anything similar?

    Thanks for any insight/tips!

    Jeff
     
  2. shabby

    shabby Diamond Member

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    Since the phone is going to detect a usb cable its only going to pull 450-500ma from the port. Some kernels allow fast charging that will trick the phone thinking its plugged into the ac outlet when its simply connected to the usb and will pull up to 1a from a usb port.
    You can also try a usb charging cable, its only good for charging, but i guess your usb tethering wont work.
     
  3. jeffason

    jeffason Member

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    Thanks Shabby. I am one step closer. I did some research and believe my kernel does support fast charge. I found an app to enable it, as well.

    However, USB 2.0 still cannot send more than 500ma, correct? So, I'd need this trick in combination with a USB 3.0 port to gain any benefits?

    If I'm on the right track here then could anyone recommend a good USB 3.0 PCI-E expansion card? I'm really not liking the USpeed one I bought which is not playing nice with my USB 2.0 devices.

    Thanks again for any insight or product recommendations.
     
  4. mfenn

    mfenn Elite Member <br> Currently on <BR> Moderator Sabb
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    Depends on your exact setup. Many laptops and motherboards provide USB charging ports that output over 1A. You can also use a Y cable to get 1A of power draw from two USB 2.0 ports.
     
  5. jeffason

    jeffason Member

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    cool, thanks mfenn. going to try out a y-cable that some other smartphone users reported success using.

    appreciate the help y'all!