Patent ID: 7310697

Claim:
A method for powering a universal serial bus (USB) device, comprising; determining when the USB device is a master device or a slave device; powering through a first switch the USB device over a USB connector using a power unit when the USB device is a slave device; and powering through a second switch located between the USB device and a second USB device over the USB connector using the USB device when the USB device is the master device; detecting a logical low on a USB identifier (ID) connector; and detecting a logical high on a VBUS connector, such that the USB device is powered over the USB ID connector using the power unit; inverting the logical low on the USB ID connector to a second logical high; and outputting a third logical high when the USB ID is inverted to the second logical high and when the logical high on the VBUS connector is detected; and closing the first switch when the third logical high is output such that the USB device is powered from the power unit coupled to the first switch.