| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a USB controller and a USB device minimizing data errors resulting from external line noises applied to a USB cable, by maximizing potential stability between a USB device circuit GND and a host FG while satisfying USB grounding specifications. <P>SOLUTION: The USB controller 1 is installed in the USB device and provides a USB interface to a host. Two power sources, bus power from the host and an external power source, are provided for the USB device. Circuits relating to the USB interface are operated on the bus power while the other circuits 2 are operated on the external power supply. In the USB device fitted with the USB controller providing the USB interface to the host, signals are insulated inside the USB device and the USB controller 1 is operated on the bus power while the other circuits 2 are operated on the external power supply. <P>COPYRIGHT: (C)2004,JPO |
