Patent ID: 8489250

Claim:
A fan control system for a computer system, said computer system comprising a fan for providing airflow to a target device of said computer system, said fan control system comprising: a power sensor for detecting power dissipated by said target device; and a controller for generating a control signal for controlling said fan according to said dissipated power, wherein a rotating speed of the fan is positively correlated with the power dissipated by the target device, and negatively correlated with a density and a heat capacity of air, a sectional area of the target device facing airflow, and a difference between a threshold operating temperature and an ambient temperature, wherein a pulse-width modulation (PWM) duty cycle of the fan corresponding to the power dissipated by the target device is adjusted relative to the PWM duty cycle in an idle state by an adjustment factor, the adjustment factor being a quotient of an airflow speed in a current state and an airflow speed in the idle state.