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The 'charging' isn't a feature of USB, it's just the device using the voltage supplied by the USB port, which the ports are always supplying (sometimes even when the computer is "off") Charging is not be require the driver and usb feature for installation.
Here is some external document for the more knowledge
http://superuser.com/questions/429097/how-to-disable-usb-charging-of-external-devices-in-windows-7
http://android.stackexchange.com/questions/77416/how-can-i-turn-off-charging-when-my-phone-connected-to-my-computer