Port power controller for USB hubs with legacy battery charge support

摘要

A system and method for efficient power management of peripheral port connections. A USB hub core is configured to detect the presence of a legacy peripheral device on a downstream port when a corresponding USB host is in a non-operational state. The USB hub core chooses a battery charger signature for the peripheral device and subsequently directs an external port power controller to simulate disconnection/reconnection of the peripheral device. The chosen signature is presented to the peripheral device. If the signature matches the expected value of the peripheral device, then the peripheral device charges its battery. Otherwise, the process of choosing a different signature and simulating disconnection/reconnection is repeated.