I'm thinking about adding more power to my laptops USB 2.0 ports, by hooking it up to a buck converter witch takes its input directly from the power connector of my laptop.

The voltage and current supplied by the charger are 19V ~4A and this is the voltage i would supply the buck converter to and then get 5V out of it and as much current as possible (i don't think the current is going to be an issue though since i wont need more than 2A anyway) and then connect these 5V to the USB power lines, i hope you get the picture!

I don't want to use a powered USB hub because its not practical and i need another power supply for no real reason as it seems.

Did anyone do something similar and do i need to pay attention to something while doing this (i don't want to mess up the ports since they are kind of custom and harder to find, and that applies to the on board hub also), thanks.

  • \$\begingroup\$ Why are you wanting to do this? A little help with the bigger picture might be useful. \$\endgroup\$
    – Andy aka
    Nov 1, 2015 at 19:05
  • \$\begingroup\$ In the second paragraph of my post i explained why id want to do this, its basically more convenient looks better and is more portable since im doing this on a laptop. \$\endgroup\$
    – adoion
    Nov 1, 2015 at 19:10
  • \$\begingroup\$ What USB device are you using that won't work with the power normally supplied by the laptop's USB ports? You can get USB leads which have two connectors on the computer end to draw power from two USB ports. \$\endgroup\$ Nov 1, 2015 at 19:13
  • \$\begingroup\$ Im using a PlayStation 2 controller to USB converter, (the blue one) and it works fine as long as i have vibration disabled but as soon vibration gets in the 60% range it kicks out and i get an error massage saying that the USB device is malfunctioning but as soon vibration gets below ~60% it kicks back in. \$\endgroup\$
    – adoion
    Nov 1, 2015 at 19:17
  • 1
    \$\begingroup\$ @AndrewMorton has the right answer: you can power the 5V line from somewhere else entirely as long as it uses the same ground. Don't back-power the port itself. \$\endgroup\$
    – pjc50
    Nov 1, 2015 at 20:41

1 Answer 1


Don't do this. You'll likely damage the internal 5 V supply in the USB port by 'back-feeding' it from the additional supply.

If the additional supply powers up after the motherboard one, then before it powers up, it'll act as a load on the motherboard, and possibly the USB port will be disabled by its own internal protection. Conversely, if it remains powered after the motherboard is shut down, likely the motherboard won't be happy.

  • \$\begingroup\$ its not fed from the motherboard its directly hooked up to the power supply, and im going to cut the back-feed to the motherboard supply \$\endgroup\$
    – adoion
    Nov 2, 2015 at 6:19
  • \$\begingroup\$ I agree with @adoion that nothing in your post precludes finding an answer to the question. \$\endgroup\$
    – HighInBC
    Nov 2, 2015 at 15:47

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