A USB device for performing communications with a second device through a USB interface while supplying electric power to the second device through a power-source supplying line in the USB interface. The USB device includes a communication unit for communicating with the second device, a power source...http://www.google.com.tw/patents/US7159132?utm_source=gb-gplus-share專利 US7159132 - USB device that provides power that is different from power prescribed in the USB standard
