Controlling CPU core voltage to reduce power consumption

摘要

A CPU operating within a low power state has its core voltage controlled to be at a nominal level or a reduced level. When the CPU is active it draws power. A CPU voltage controller maintains the CPU core voltage at the nominal level to meet the fluctuating power needs of the CPU. When the power drawn from the CPU becomes constant (i.e., the CPU power needs are being met, perhaps with a "cushion'), the CPU voltage controller reduces the core voltage to a reduced level. The CPU core voltage remains at the reduced level until increased power needs are anticipated. One method for anticipating increased power needs is to monitor PCI bus arbitration lines.