Patent ID: 7802116

Claim:
An apparatus, comprising: an integrated circuit (IC) comprising a plurality of subsystems, at least one subsystem comprising: subsystem circuitry configured to perform at least one function of said IC, said subsystem circuitry comprising at least one memory storage element; subsystem voltage regulator circuitry configured to generate a subsystem power supply for said subsystem circuitry based on, at least in part, a main power supply; and subsystem power management circuitry configured to detect the activity of said subsystem circuitry and; said subsystem power management circuitry is further configured to control said subsystem voltage regulator circuitry to turn off said subsystem power supply, if said subsystem circuitry is inactive; said at least one memory storage element configured to save state information related to said subsystem circuitry if said subsystem power supply is turned off; said subsystem power management circuitry is further configured to detect activity of said subsystem circuitry and control said voltage regulator circuitry independently of an operating system.