W83627THF_06 Datasheet, PDF (36/142 Pages) Winbond – Winbond LPC I/O

W83627THF/W83627THG
5.5.1 Thermal Cruise mode
There are maximum 3 pairs of Temperature/FANOUT control at this mode: SYSTIN with
SYSFANOUT, CPUTIN with CPUFANOUT, AUXTIN with AUXFANOUT. At this mode, W83627THF
provides the Smart Fan system which can control the fan speed automatically depend on current
temperature to keep it with in a specific range. At first a wanted temperature and interval must be set
(ex. 55 °C ± 3 °C) by BIOS, as long as the real temperature remains below the setting value, the fan
will be off. Once the temperature exceeds the setting high limit temperature ( 58°C), the fan will be
turned on with a specific speed set by BIOS (ex: 3.75 V) and automatically controlled its DC voltage
output with the temperature varying. Three conditions may occur :
(1) If the temperature still exceeds the high limit (ex: 58°C), DC Fan output voltage will increase
slowly. If the fan has been operating in its fully speed but the temperature still exceeds the high
limit(ex: 58°C) after 3 minutes, a warning message will be issued to protect the system.
(2) If the temperature goes below the high limit (ex: 58°C), but above the low limit (ex: 52°C), the fan
speed will be fixed at the current speed because the temperature is in the target area(ex: 52 °C ~
58°C).
(3) If the temperature goes below the low limit (ex: 52°C), DC Fan output voltage will decrease slowly
to 0 until the temperature exceeds the low limit.
Figure 5-9 and 5-10 give the illustration for Thermal Cruise Mode .
Tolerance
Target Temperature
Tolerance
58`C
55`C
52`C
A
B
C
D
DC
Output
Voltage
5 ^{Fan Start = 1.875 V}
2.5
0
Figure 5-9
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Publication Release Date: September 26, 2006
Revision 1.2