US Patent 7752471 Adaptive USB mass storage devices that reduce power consumption

A bridge circuit that is located between a peripheral device and a USB connection to a host. The bridge stores data indicating the amount of power required to execute each particular command. When a command is received, the command is executed if this list indicates that a particular command can be executed with the available power. If the list indicates that the command can not be executed with the available power, the command is either rejected or delayed. The bridge may include a power storage device that accumulates and stores power. In this case the list of commands would indicate commands that can be delayed until the storage device has accumulated sufficient power.