Re: USB interface question.

"siliconmike" <siliconmike@xxxxxxxxx> wrote in message
news:1149930411.747592.301740@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I'm newbie at USB, if someone can help it would be wonderful:

I'm envisioning a gadget that would take input from a USB port on a PC
(or any USB host). And it would act as a UPS for four downstream USB
devices, providing currents upto 1A.

In other words, the gadget would have 4 USB sockets for output, capable
of providing upto 1A to devices connected to it.

Well, any USB hub with a wall wart would do this. The only problem is that
1A is far beyond the USB specs. Any device is not allowed to consume more
than 100mA from the start and after negotiation with the host, it may
consume up to 500mA. If you draw more, you'll get a "USB overcurrent"
message. This means that a hub can measure the current of each port and
shuts down a port that is loaded to heavy.

Meindert


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