Acoustic Fan Speed Control
R
Thermal/Mechanical Design Guide
57
Figure 19. Temperature Range = 5 °C
0
500
1000
1500
2000
2500
3000
3500
Time (s)
RP
M
40
45
50
55
60
65
70
75
80
T
d
io
d
e
(
C
)
Fan RPM
Tdiode
Tcontrol
Tlow
An alternate would be to consider a slightly larger value such as T
RANGE
= 10 °C. In this case the
design is trading off the acoustic margin for thermal margin.
•
There is increased granularity in the fan speeds.
•
Fan speed oscillation are significantly reduced
•
Maximum fan speed is lower
The rate of change of
Ψ
CA
vs. RPM is an exponential curve with a larger decrease at the beginning
of the fan acceleration than as the maximum speed is approached. By having the fan start to
accelerate at a lower T
DIODE
reading the thermal solution can keep up with rate of change in
processor power. The rate of change in acoustics (dBA) is more linear with RPM. When
comparing these two metrics, the choice of a larger T
RANGE
value becomes a more acceptable
trade off. Figure 20 graphs the system at the same conditions as in Figure 19, but T
RANGE
= 10°.
Содержание 640 - Pentium 4 640 3.2GHz 800MHz 2MB Socket 775 CPU
Страница 14: ...Introduction R 14 Thermal Mechanical Design Guide ...
Страница 38: ...Thermal Management Logic and Thermal Monitor Feature R 38 Thermal Mechanical Design Guide ...
Страница 52: ...Intel Thermal Mechanical Reference Design Information R 52 Thermal Mechanical Design Guide ...
Страница 60: ...Acoustic Fan Speed Control R 60 Thermal Mechanical Design Guide ...
Страница 72: ...Heatsink Clip Load Metrology R 72 Thermal Mechanical Design Guide ...
Страница 97: ...Mechanical Drawings R Thermal Mechanical Design Guide 97 Figure 48 Reference Clip Drawings Sheet 1 ...
Страница 98: ...Mechanical Drawings R 98 Thermal Mechanical Design Guide Figure 49 Reference Clip Drawings Sheet 2 ...
Страница 99: ...Mechanical Drawings R Thermal Mechanical Design Guide 99 Figure 50 Reference Fastener Sheet 1 ...
Страница 100: ...Mechanical Drawings R 100 Thermal Mechanical Design Guide Figure 51 Reference Fastener Sheet 2 ...
Страница 101: ...Mechanical Drawings R Thermal Mechanical Design Guide 101 Figure 52 Reference Fastener Sheet 3 ...
Страница 102: ...Mechanical Drawings R 102 Thermal Mechanical Design Guide Figure 53 Reference Fastener Sheet 4 ...
Страница 103: ...Mechanical Drawings R Thermal Mechanical Design Guide 103 Figure 54 Clip Heatsink Assembly ...
Страница 104: ...Mechanical Drawings R 104 Thermal Mechanical Design Guide Figure 55 Intel R RCBFH 3 Reference Solution Assembly ...
