F71862
a. Once temp. is under 40°C, the lowest fan speed keeps 50% PWM duty
b. Once temp. is over 40°C,60°C, the fan speed will vary from 70% to 100% PWM duty
and increase with temp. level.
c. Once temp. keeps in 55°C, fan speed keeps in 70% PWM duty
d. If set the hysteresis as 3°C (default 4°C), once temp reduces under 57°C, fan speed
reduces to 70% PWM duty and stays there.
Linear auto mode
Otherwise, F71862 supports linear auto mode. Below has a example to describe this
mode. More detail, please refer the register description.
A. Linear auto mode (PWM Duty I)
Set temperature as 70°C, 40°C and Duty as 100%, 70%, 40%
PWM duty
100%
70 Degree C
hysteresis 65 Degree C
70%
40 Degree C
40%
Temp.
Fan Speed
a
b
c
d
a. Once temp. is under 40°C, the lowest fan speed keeps 40% PWM duty
b. Once temp. is over 40°C and under 70°C, the fan speed will vary from 40% to 70%
PWM duty and linearly increase with temp. variation. The temp.-fan speed monitoring
and flash interval is 1sec.
c. Once temp. goes over 70°C, fan speed will directly increase to 100% PWM duty (full
speed)
d. If set the hysteresis as 5°C(default is 4°C), once temp reduces under 65°C (not 70°C),
fan speed reduces from 100% PWM duty and decrease linearly with temp..
FAN_FAULT#
Fan_Fault# will be asserted when the fan speed doesn’t meet the expected fan speed
within a programmable period (default is 11 seconds) or when fan stops with respect to
PWM duty-cycle which should be able to turn on the fan. There are two conditions may
48
July, 2008
V.28P
FINTEK [ FEATURE INTEGRATION TECHNOLOGY INC. ]
