F81867 Datasheet, PDF (42/315 Pages) Feature Integration Technology Inc. – 6 UARTs μSuper IO With 128 Bytes FIFO and Power Saving Functions

F81867
Fig 7-10 Linear mode fan control illustration
a. Once the temperature is lower than 40°C, the lowest fan speed keeps in the 50% PWM duty
b. Once the temperature becomes higher than 40°C, 50°C and 60°C, the fan speed will vary from
50% to 80% PWM duty linearly with the temperature variation. The temp.-fan speed monitoring
flash interval is 1sec.
c. Once the temperature goes over 70°C, the fan speed will directly increase to 100% PWM duty
(full speed).
d. If set the hysteresis is 5°C (default is 4°C), once the temperature becomes lower than 65°C
(instead of 70°C), the fan speed will reduce from 100% PWM duty and decrease linearly with the
temperature.
B. Linear auto mode (RPM%)
Set the temperature as 70°C, 60°C, 50°C, 40°C and the corresponding fan speed is 6,000 RPM,
4,800 RPM, 4,200 RPM, 3,600 RPM and 3,000 RPM (assume the Max Fan Speed is 6,000 RPM).
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Dec, 2011
V0.12P