USB Host Mode Power Requirements

[firefly2442]

Hello. I have a GP2X handheld and I am trying to add USB functionality in an external cable. I bought a battery powered USB hub which I would like to use as a hub and power supply for any peripherals. I am using this usb filter to connect between the GP2X and the USB hub. My question is, since the USB hub already has batteries and powers the peripherals, what's the point of the VUSB 5 volt line between the hub and GP2X? Is it even necessary? If it is, where is the power going to be used? Also, if it's needed, where can I find a cheap rechargeable AA battery pack to provide the 5 volts? Thanks!

 

[Casawi]

I think that the 5v line is to power up your handheld device. If your handheld device has power then the USB hub's batteries will be sufficient. However, you still need the line to make sure that any device plug to USB has a voltage reference of 5V to communicate.
So I think the 5v is to either power up ur device and/or voltage reference to make sure the data lines spike up to 5v for other devices to detect ur signal.

Hope this made sense

Yassine