USB Power From Your VGA Port


[gmgfarrand] needed an extra USB port to power some devices. Since he just needed power, and no data, he slapped together this quick adapter that pulls power from the vga port instead. While we’re not sure if this could possibly damage your video card if you pull too much power from it, we’re happy to see someone being original. That VGA port goes unused so often, this adapter might just make it a tad more useful.

[thanks Adam]

41 thoughts on “USB Power From Your VGA Port

  1. My only concern is that someone will plug in a current hogging device. I’m not sure of the video card +5V protection circuitry, but using the port without some protection circuit on your end is a little stupid. At least put in a low wattage resistor that can blow. The +5 rail is rated for at least 300mA and upto 1A.

    I found this from :

    “Devices that comply with the DDC host system standard typically provide supply voltage on pin #9 of the standard 15-pin VGA connector. The voltage is 5V ±5% and supplies a minimum of 300mA to a maximum of 1A.”

    1. The 5V on the VGA pin 9 is to power up an EDID EEPROM for getting some ID signals from the monitor to better identify several parameters on certain monitors.

    2. This is exactly what I need. I have an old Led TV that has a HDMI port for my Roku stick but there’s no USB port to power the Roku stick. I don’t want to run 2 seperate cords or and extension cord when there is available power from other connectors behind the TV. I just need an adapter so the roku stick can draw 5v of power from one of thes other connectors. All it has is a VGA and an S-video port.

  2. Why? Because we can. The same question is applicable to most hacks shown here.

    Really though, this adds an extra charging port to small netbooks and such which may only have two. Also is supposedly gives you more than the 500ma that you get from a normal USB port, so you can charge devices faster and such.

  3. I would better do a Y-USB-Adapter
    one female only connected to the power cords and the other straight thru to the host port
    most usb ports offer slightly more than 500 mA, if more current is pulled, most of them just start pulsing instead of instantly shut down. the real shutdown of the port mostly is near 900 mA. at least on boards I’ve tested

  4. @spork

    Comment post from author on

    gmgfarrand @ Nov 26th 2008 1:24PM

    THANKS for the comments!!!
    The main use was to be able to power my LENOVO DVD Burner which has the option not only to use a DC brick, or power from USB. So I power it from the VGA port and use only ONE of my USB ports for the data.

    Or, since they hardly ever give you a power supply with a compact USB hub, I modded the power jack on it with a MALE USB plug so that I can power it off my VGA port. :)

    BTW, there wasn’t alot of planning involved.
    I just looked over at the EEEPC 1000H on my desk and thought “hmm… I wonder…”

  5. awesome idea. it’s great for netbooks and laptops, which looks like what it’s been designed for. Heck, I’ve got a 15″ MBP (last model pre-unibody) here that’s my main work computer, and I end up taking my iPhone charger around with me to LAN parties ’cause the darn thing has 2 USB ports, and I store my games and music on an external drive… which takes a USB port for power. And I need an external mouse… so yeah.

    i would assume it does, but anybody know for certain if a dvi port has similar current available @ 5v? I’d even be willing to step down from a higher voltage via a 7805 just to be sure I’d have enough current available (I *do* use the port every once in a while, and I can’t afford frying anything). I’ll probably just have to look it up, plus my current configuration isn’t really that bad anyway… it’d just be nice to not have to plug into the wall for it.

  6. @Matt:

    Per the DVI spec R1.0, the “+5V signal is required in a DVI compliant system… the power pin must be able to supply a miniumum of 55mA and the monitor may not draw more than 50mA.”

    To be on the safeside, don’t do this hack on your DVI port.

  7. carl and mike, some good points, guess I had already thought of that when I bought the lenovo, the model with an optical drive built in. (If you were worried about weight or power drain, you could remove it)

    I was thinking about a desktop PC. Extra USB ports there are easy to come by.

    Still, that was just my initial reaction.

  8. I really like this hack, I’ve got two Eee’s, a year old 701 and a week old 900, along with a slimline USB DVD/CD burner which happily runs off one USB port when reading but needs 1.5A when burning, so I’ll have to give this a try to see if I can get one/both of my machines to burn a DVD without requiring a 1A+ 5V PSU plugged into the burner.

  9. @haku:

    See the first comment that i posted today. I would not recommend it because it supports up to 1amp. You’re saying your burner requires 1.5A… do it at your own risk i guess.

  10. At last, a hack! :)
    @Elliott, my video card has 2 output ports, so yes, this is indeed useful in a lot of circumstances. Now, I wonder if you could arbitrarily control the DDC channel from software and actually attach a smart device to the port. Why occupy one USB port when there’s a free DVI/VGA one.

  11. Sorry, I have 3 PCI-E video cards in my PC, and all the “VGA” ports are in use :P

    (it is a $50 nforce4 board, nothing special, two of the cards run on PCI-e x1 with a simple physical mod)

  12. Hey GUYS!

    I’ve been coming to this site for YEARS, and I am glad that my random act of boredom actually resulted in something useful. :)

    I posted on the INSTRUCTABLES site that there will be a newer version in the next week or so that has protection on it, just in case.

    Also, just for giggles, different colors of rubberized coating.


  13. Somewhere, I have a cable that draws +5v from the PS/2 port. It was to power a Xircom parallel port ethernet adapter.

    A while back, I rescued a number of such devices, for grins, from otherwise being ground up, compacted, and sent to Africa or something. They make great little enclosures…but I’m going to hold on to one or two of them in case I ever need quick ethernet access to a junky old box.

    I’ve had a bad mic fry the mic input on my motherboard (Just after I could have returned the board!), so in general I’m wary of doing something like this unless I know it’s safe… I’m far more likely to take a couple few minutes to build a +5v regulated power supply with a USB port output. But that’s just the geek in me. :P

  14. use this product to hook two monitors with one VGA port. I have a Mac Mini so basically I have an adapter from mini DVI to a VGA, then I have the VGA splitter running from the adapter to the two screens. One of my “monitors” is my 32′ TV that is hanging on my wall. I use the computer as my DVD player so its nice to not have to keep connection one screen up then unhooking to hook the other up. Now they both show the same view. The splitter works great. Only problem I seem to have is on my actual monitor (21.5″) at times when there are darker colors on a web page, the colors seem to be scrolling down. This can be very annoying. I’m not sure why this only happens at times, but it never happens on my actual TV. Besides that, this product works great.

    1. I don’t think it will work that way. This is intended to draw power from a vga source. The vga port on your monitor is not a source, it receives power and data. I may be wrong tho, get a multimeter and try it. If you see 9v there then you can make it work.

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