Is there any way to force the macbook pro to feed the additional 500mA to a usb plug? I know the iPhone triggers the extra 500mA bringing up the total to 1000mA but all other devices don't have that ability. My PS Vita draws so much power it requires to recharge while it is off via the USB plug. Even then it takes forever. Is it possible to force it so that the computer charges it at 1000mA?