Abstract: Power management techniques for a Universal Serial Bus (USB) include determining an idle period on one or more USB ports by a main controller circuit of a USB host controller. The main controller circuit signals a suspend to a Power Management Controller (PMC) sub-circuit of the USB host controller, in response to the determined idle period. The PMC sub-circuit stores one or more operating parameters of the one or more USB ports in response to the suspend signal. The PMC sub-circuit also maintains the idle state on the one or more USB ports in response to the suspend signal. Thereafter, the main controller circuit is placed in a low energy state while the PMC sub-circuit maintains the idle state.

Abstract: A USB host for wakeup from a sleep state includes a hold memory, a USB host controller, and a USB driver. When going to sleep, the USB driver sends a suspend command to the USB host controller in response to receiving a sleep command. The USB driver also reads a controller context from the USB host controller and saves the controller context in the hold memory. Thereafter, the USB driver turns off one or more supply potentials and one or more clocks in the host controller, and returns a sleep acknowledgement. While in sleep, the interface pins are placed in a hold state and notification to the operating system are disabled.

Abstract: A USB host for wakeup from a sleep state includes a hold memory, a USB host controller, and a USB driver. When going to sleep, the USB driver sends a suspend command to the USB host controller in response to receiving a sleep command. The USB driver also reads a controller context from the USB host controller and saves the controller context in the hold memory. Thereafter, the USB driver turns off one or more supply potentials and one or more clocks in the host controller, and returns a sleep acknowledgement. While in sleep, the interface pins are placed in a hold state and notification to the operating system are disabled.