Patent ID: 9189434
Filing Date: 2015-11-17
Classification: G06F

Abstract:
1. A method of operating a universal serial bus (USB) host device, the method comprising: starting a first data transfer in an on-state; entering a suspend state when an idle-delay time elapses after the first data transfer is completed; making a transition from the suspend state to the on-state after performing a resuming operation when a second data transfer is requested; and controlling the idle-delay time based on a compared result of a current miss rate and at least two predetermined miss rates, wherein the current miss rate is obtained based on a current suspend time in the suspend state, wherein the current suspend time is an elapsed period until a transition from the suspend state to the on-state after a transition from the on-state to the suspend state, wherein the controlling of the idle-delay time comprises: comparing the current suspend time with a predetermined minimum suspend time; counting a miss when the current suspend time is equal to or smaller than the minimum suspend time; and counting a hit when the current suspend time is greater than the minimum suspend time, and wherein the current miss rate is a ratio of a number of counted misses to a total number of counted misses and hits.