Patent ID: 9122813
Filing Date: 2015-09-01
Classification: G06F

Abstract:
1. A system configured to act as a USB host, comprising: a battery; a USB charging port for coupling to USB devices; device logic, wherein the device logic is configured to: determine that a USB device is coupled to the USB charging port, thereby providing a USB coupling between the USB host and the USB device; determine whether the USB device is providing power via the USB coupling, wherein the USB host detects a change in current direction on a Vbus line of the USB coupling; and based on detecting a change in current direction on the Vbus line, the USB host compares the voltage provided by the Vbus line and a voltage available from the USB host to detect a back drive indication; if determined that the USB device is not providing power, the device logic is further configured to: determine a power level for providing power to the USB device wherein the power level is determined based on one or more handshake procedures; and provide power at the determined power level to the USB device via the USB coupling; if determined that the USB device is providing power, the device logic is further configured to: determine whether the power provided by the USB device can be used to charge the battery of the USB host; and based on determining that the power provided by the USB device can be used to charge the battery of the USB host, charge the battery using power provided by the USB device via the USB coupling.