Re: USB 5volt power

On 15 Aug 2006 16:46:08 +0200, ArameFarpado
<a-farpado.spam@xxxxxxxxxx> wrote:

hi all

i have a situation with USB ports that drop down the 5volt power in pins
1 & 4, when this appens, all devices connected shuts down.
(funcking VIA controllers)
i was hopping to solve this without spending more money (this is a bad luck
computer that allready had to replace a lot of components and belongs to a
family with low resources). I've read about one possible solution that goes
by installing a "self-powered USB-HUB" but it costs ? and i'm not sure that
will solve the problem.
so... i was thinking about desconect the 5 volts pins on the usb port (those
that come from the controller) and connect 5volt directly from the main
power unit, but i don't know if this is a good idea... will the controller
still recognize devices attached and put then to work? or the controller
needs to detect some mA on the power lines to detect devices?

Does anybody allready tried this?

Advices please.

Many thanks :)
ArameFarpado


There are 2 per-port limits on the power available from a USB port.
One limit for devices that don't tell the USB controller how much
power they need and another limit for devices that do specify their
loading. If a device draws more than the first limit and does not
tell the controller, you may encounter problems. If a device
specifies it's current requirements but exceeds that specification,
you may encounter problems.

There is also a maximum total current limit for the particular USB
controller being used. If that total current limit is exceeded, the
chip will (usually) shut down. This sounds like the problem you are
describing. There are two solutions - connect fewer devices at one
time (example: printer and scanner not usually in use simultaneously)
or add an external powered hub.

John



.

Relevant Pages

  • Re: Power Surge On Hub Port
    ... There is no surge. ... to draw more power than the USB port permits. ... USB controller programming error? ...
    (microsoft.public.windowsxp.help_and_support)
  • Re: Grow-Tron, For Sale!
    ... Then, with the controller logic removed, there are questions about ... "DO NOT PLUG THE GROW-TRON POWER SUPPLY JACK PLUGS INTO THE MEDIA CARD ... So, that levity aside as I'm still an idiot about the LEDs, hmm... ...
    (rec.gardens)
  • Re: Boot process not starting
    ... When I push the power button all the fans come to life and spin for 14 seconds, then they stop for a few seconds and then start up again for 14 seconds. ... No I haven't looked at the socket contacts carefully because I used the last of my Arctic Silver thermal paste for re-assembling after checking the cooler fan pushpins but I will have to have another look at this. ... and the memory controller is set up. ... a microcontroller inside them. ...
    (alt.comp.hardware.pc-homebuilt)
  • Re: Computer always restarts
    ... S5" option in the power tab of BIOS is inaccessible-both in the BIOS ... controller, then it cannot command power off. ... in HAL) for that particular motherboard. ...
    (microsoft.public.windowsxp.hardware)
  • Re: Boot process not starting
    ... When I push the power button all the fans come to life and spin for 14 seconds, then they stop for a few seconds and then start up again for 14 seconds. ... No I haven't looked at the socket contacts carefully because I used the last of my Arctic Silver thermal paste for re-assembling after checking the cooler fan pushpins but I will have to have another look at this. ... and the memory controller is set up. ... a microcontroller inside them. ...
    (alt.comp.hardware.pc-homebuilt)