Patent ID: 8237387
Filing Date: 2012-08-07
Classification: G05D,G06F

Abstract:
1. A system for controlling a duty cycle of a central processing unit (CPU) fan included in a computer device, the computer device comprising a CPU and a thermal sensor, the system comprising: a parameter setting module operable to set an initial duty cycle of the fan, an adjustment step, and a temperature constant; a duty cycle adjustment module operable to adjust a duty cycle of the fan to a first fan duty cycle according to the initial duty cycle and the adjustment step, and adjust the duty cycle to a second fan duty cycle according to the first fan duty cycle and the adjustment step; a temperature obtaining module operable to obtain a system environment temperature of the computing device sensed by the thermal sensor, obtain a first CPU temperature by the thermal sensor when the fan operates at the first fan duty cycle, and obtain a second CPU temperature by the thermal sensor when the fan operates at the second fan duty cycle; a temperature calculation module operable to calculate a first temperature change of the CPU according to the system environment temperature and the first CPU temperature, calculate a second temperature change of the CPU according to the system environment temperature and the second CPU temperature, and calculate a temperature difference between the first temperature change and the second temperature change; and a duty cycle controlling module operable to obtain an optimum duty cycle range of the fan according to the first fan duty cycle and the second fan duty cycle when an absolute value of the temperature difference is less than the temperature constant, and control the fan to operate at the optimum duty cycle range.