U.S. patent application number 12/025518 was filed with the patent office on 2009-06-18 for intelligent cooling fan device and fan rotation speed controlling method thereof.
This patent application is currently assigned to INVENTEC CORPORATION. Invention is credited to Chi-Tsung Chang, Ying-Chih Lu.
Application Number | 20090155045 12/025518 |
Document ID | / |
Family ID | 40753492 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090155045 |
Kind Code |
A1 |
Chang; Chi-Tsung ; et
al. |
June 18, 2009 |
INTELLIGENT COOLING FAN DEVICE AND FAN ROTATION SPEED CONTROLLING
METHOD THEREOF
Abstract
A fan cooling device and a method of controlling a fan rotation
speed are provided. The fan cooling device includes a thermo
sensor, a thermo monitor unit, a processing unit, a driving unit,
and a fan. The thermo monitor unit compares the sensed result from
the thermo sensor with at least one threshold, and decides whether
or not to send an interrupt event according to the compared result.
The processing unit executes an interrupt service according to the
interrupt event, and then sets and outputs a value of the fan
rotation speed. The driving unit drives the fan and controls the
rotation speed of the fan according to the value of the fan
rotation speed. The fan sends out a wind flow to reduce the
internal temperature of a computer system or a CPU.
Inventors: |
Chang; Chi-Tsung; (Taipei
City, TW) ; Lu; Ying-Chih; (Taipei City, TW) |
Correspondence
Address: |
J C PATENTS, INC.
4 VENTURE, SUITE 250
IRVINE
CA
92618
US
|
Assignee: |
INVENTEC CORPORATION
Taipei City
TW
|
Family ID: |
40753492 |
Appl. No.: |
12/025518 |
Filed: |
February 4, 2008 |
Current U.S.
Class: |
415/17 |
Current CPC
Class: |
F01P 2025/66 20130101;
F01P 7/04 20130101; F01P 2025/08 20130101 |
Class at
Publication: |
415/17 |
International
Class: |
F01B 25/00 20060101
F01B025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2007 |
TW |
96147648 |
Claims
1. A fan cooling device, comprising: a thermo sensor, for sensing
an operating temperature and outputting a sensed result; a fan, for
providing a wind flow to reduce the operating temperature; a thermo
monitor unit, coupled to the thermo sensor, for comparing the
sensed result with at least one threshold, and deciding whether or
not to send an interrupt event according to a compared result; a
processing unit, coupled to the thermo monitor unit, for executing
an interrupt service according to the interrupt event to set and
output a value of a fan rotation speed; and a driving unit, coupled
between the processing unit and the fan, for driving the fan and
controlling a rotation speed of the fan according to the value of
the fan rotation speed.
2. The fan cooling device according to claim 1, wherein the thermo
monitor unit comprises a plurality of thresholds for defining a
plurality of temperature control ranges.
3. The fan cooling device according to claim 1, wherein the
interrupt service comprises a rotation speed table, and wherein
once the interrupt event occurs, the interrupt service reads the
sensed result from the thermo sensor, looks up the rotation speed
table to obtain a corresponding value of the fan rotation speed,
and outputs the value of the fan rotation speed to the driving
unit.
4. The fan cooling device according to claim 1, wherein the
operating temperature is an internal temperature of a computer
system.
5. The fan cooling device according to claim 4, wherein the
operating temperature is a temperature of a central processing unit
(CPU).
6. A method of controlling a fan rotation speed, comprising:
sensing an operating temperature to obtain a sensed result;
comparing the sensed result with at least one threshold to obtain a
compared result; deciding whether or not to send an interrupt event
according to a compared result; executing an interrupt service
according to the interrupt event to set a value of a fan rotation
speed; and driving a fan and controlling a rotation speed of the
fan according to the value of the fan rotation speed to provide a
wind flow to reduce the operating temperature.
7. The method of controlling a fan rotation speed according to
claim 6, further comprising: setting a plurality of thresholds to
define a plurality of temperature control ranges, wherein when the
sensed result indicates that the operating temperature falls within
one of the temperature control ranges, the interrupt service sets a
corresponding value of the fan rotation speed.
8. The method of controlling a fan rotation speed according to
claim 6, further comprising providing a rotation speed table,
wherein once the interrupt event occurs, the interrupt service
looks up the rotation speed table according to the sensed result,
so as to obtain the corresponding value of the fan rotation
speed.
9. The method of controlling a fan rotation speed according to
claim 6, wherein the operating temperature is an internal
temperature of a computer system.
10. The method of controlling a fan rotation speed according to
claim 9, wherein the operating temperature is a temperature of a
CPU.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 96147648, filed on Dec. 13, 2007. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to a temperature
control device and a method thereof, and more particularly, to a
cooling fan device and a method of controlling a fan rotation
speed.
[0004] 2. Description of Related Art
[0005] With the rapid development of technology, computer hardware
has been developed rapidly in recent years, for example, central
processing units (CPUs) commonly used by hardware devices such as
desktop computers, laptop computers, and even servers and
workstations. The clock speed of the CPUs becomes increasingly
high, so as to cater to the mass's requirements on processing an
increasingly large amount of data and reducing the processing time.
With the increase of the clock speed of the CPUs, the surface
temperature of the CPUs also correspondingly rises. If no cooling
device is installed, the system crash may occur, or even the
hardware devices may be damaged. Therefore, fans must be installed
to control the surface temperature of the CPUs within a safe range.
However, when designing the rotation speed of the fan, the
manufacturer often designs taking very extreme use environments
into consideration, so as to ensure that the surface temperature of
the CPU is well controlled to enable the device to operate normally
in the safe range under all operating environments. However, in
actual usage, the extreme environments set by the manufacturer
seldom encounters. In this case, the fan rotating at a very high
speed does no good to the CPU, but generates noise, which may
adversely affect the hardware device and causes problems to the
user. Moreover, this design consumes much electric power, so the
performance of the fan in cooling the CPU is rather poor.
[0006] In view of the above, in the early days, some manufacturers
have proposed a method of using BIOS to control the fan rotation
speed. However, as the BIOS controls the fan rotation speed through
a segmented variable speed controlling mode, when the program is
converted, the rising temperature of the CPU generates even more
noise due to the higher acceleration of the fan. Therefore, this
design still has its own disadvantages. Currently, the most widely
applied method of automatically controlling the fan rotation speed
is as shown in FIG. 1, in which the environment temperature is
detected in a polling mode through a software program, so as to
adjust the fan rotation speed, such that the system maintains at a
stable environment temperature. When the temperature is lower than
a preset minimum temperature T.sub.MIN, the fan operates at a
minimum output power P.sub.MIN; when the temperature is higher than
a preset maximum temperature T.sub.MAX, the fan operates at a
maximum output power P.sub.MAX; when the temperature falls between
T.sub.MIN and T.sub.MAX, theoretically, the output power under
which the fan operates is changed linearly, i.e., the output power
and rotation speed of the fan are automatically changed with the
temperature. However, the actual test result shows that, when the
temperature falls between T.sub.MIN and T.sub.MAX, the output power
under which the fan operates does not change linearly. At this
time, complicated mathematical formulas must be designed to
calculate the corresponding relationship between each temperature
within the temperature range and the output power of the fan. Thus,
circuit elements and software for performing the mathematical
operations must be additionally installed, so the design cost and
element cost are increased accordingly. Moreover, the manner of
adjusting the fan rotating speed through using the software program
to detect the temperature in a polling mode through the BIOS has a
rather poor performance, and consumes excessive large power.
SUMMARY OF THE INVENTION
[0007] Accordingly, the present invention is directed to a fan
cooling device, which does not require additional circuit elements
and software for performing complicated mathematical operations,
and has lower design cost and element cost.
[0008] The present invention is also directed to a method of
controlling a fan rotation speed, which does not use software
programs to detect temperature in a polling mode through BIOS.
Thus, the performance of the fan can be effectively increased, and
the power consumption is effectively reduced.
[0009] As embodied and broadly described herein, the present
invention provides a fan cooling device, which includes a thermo
sensor, a fan, a thermo monitor unit, a processing unit, and a
driving unit. The thermo sensor senses an operating temperature and
outputs a sensed result. The fan provides a wind flow to reduce the
operating temperature. The thermo monitor unit is coupled to the
thermo sensor for comparing the sensed result with at least one
threshold, and deciding whether or not to send an interrupt event
according to the compared result. The processing unit is coupled to
the thermo monitor unit for executing an interrupt service
according to the interrupt event, so as to set and output a value
of the fan rotation speed. The driving unit is coupled between the
processing unit and the fan for driving the fan and controlling the
rotation speed of the fan according to the value of the fan
rotation speed.
[0010] The present invention also provides a method of controlling
a fan rotation speed, which includes the following steps. First, an
operating temperature is sensed to obtain a sensed result. Next,
the sensed result is compared with at least one threshold to obtain
a compared result. Next, whether or not to send an interrupt event
is decided according to the compared result. Next, an interrupt
service is executed according to the interrupt event so as to set a
value of the fan rotating speed. Next, the fan driven and the
rotation speed of the fan are controlled according to the value of
the fan rotation speed so as to provide a wind flow to reduce the
operating temperature.
[0011] In an embodiment of the present invention, the thermo
monitor unit has a plurality of thresholds for defining a plurality
of temperature control ranges, such that the fan is controlled to
operate at different rotation speeds under different
temperatures.
[0012] In an embodiment of the present invention, the method of
controlling a fan rotation speed further includes providing a
rotation speed table. Once the interrupt event occurs, the
interrupt service looks up the rotation speed table according to
the sensed result, so as to obtain a corresponding value of the fan
rotation speed.
[0013] To sum up, the present invention can achieve the above
function simply by using the interrupt event, and the interrupt
service of BIOS or driver, and through looking up the table. Thus,
not only the program architecture required by the software is
greatly simplified, but also the performance of the fan is also
effectively improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0015] FIG. 1 is a power-temperature curve diagram of a
conventional method of automatically controlling a fan rotation
method.
[0016] FIG. 2 is a structural view of a fan cooling device
according to an embodiment of the present invention.
[0017] FIG. 3A is a flow chart of controlling a fan rotation speed
according to an embodiment of the present invention.
[0018] FIG. 3B is a detailed flow chart of controlling a fan
rotation speed according to an embodiment of the present
invention.
[0019] FIG. 4 is a flow chart of Step S36' as another implementing
manner of an interrupt service (Step S36) shown in FIG. 3B
according to an embodiment of the present invention.
DESCRIPTION OF THE EMBODIMENTS
[0020] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers are used in the drawings and the description
to refer to the same or like parts.
[0021] In the design of the current computer systems (e.g.,
personal computers, servers, and workstations), the thermo monitor
function is considered as an important factor, in which the thermo
monitor motion for the system and CPU plays an important role, and
another important relevant function lies in the control of the fan
rotation speed. The temperature of the CPU changes as the operating
system is operated, so the rotation speed of the fan must be
adjusted by the system. Embodiments of the present invention are
described below, in which the intelligent cooling fan device and
the method of controlling a fan rotation speed are used to maintain
the system at a stable environment temperature.
[0022] FIG. 2 is a structural view of a fan cooling device
according to an embodiment of the present invention. The fan
cooling device includes a thermo sensor 21, a thermo monitor unit
22, a processing unit 23, a driving unit 24, and a fan 25. The
thermo monitor unit 22 is coupled to the thermo sensor 21. The
processing unit 23 is coupled to the thermo monitor unit 22. The
driving unit 24 is coupled between the processing unit 23 and the
fan 25.
[0023] Hereinafter, the operation modes of the elements in this
embodiment are described below with reference to FIGS. 2 and 3A. In
Step S33, the thermo sensor 21 senses the operating temperature
within the computer system or the operating temperature of devices
such as CPU, and outputs the sensed result to the thermo monitor
unit 22. In Step S34, the thermo monitor unit 22 compares the
sensed result of the thermo sensor 21 with at least one threshold.
In Step S35, the thermo monitor unit 22 decides whether to send an
interrupt event to the processing unit 23 or not according to the
compared result. If the sensed result reaches the threshold, the
process continues to perform Step S36. If the sensed result is
lower than the threshold, the process enters into Step S37 to
maintain the original value of the fan rotation speed. Next, in
Step S38, the driving unit 24 drives the fan 25 and controls the
rotation speed of the fan 25 according to the original fan rotation
speed.
[0024] In Step S36, if the processing unit 23 receives the
interrupt event sent from the thermo monitor unit 22, the
processing unit 23 executes an interrupt service according to the
interrupt event, so as to set and output the value of the fan
rotation speed to the driving unit 24. Detailed steps of the
interrupt service will be described later. In Step S38, the driving
unit 24 drives the fan 25 and controls the rotation speed of the
fan 25 according to the value of the fan rotation speed provided by
the processing unit 23. Upon receiving the value of the fan
rotation speed sent from the driving unit 24, the fan 25 provides
the wind flow to reduce the operating temperature. Finally, the
process returns to Step S33 again.
[0025] Generally, before entering the operating system, the
computer system is booted and loaded with some software programs
required by the system. In FIG. 3B, the process of FIG. 3A is
resumed, and the power on self test (POST) steps S31-S32 are
further illustrated, as well as the detailed sub-steps S36a-S36c of
the interrupt service step S36. Referring to FIGS. 2 and 3B, the
POST procedure includes two steps: setting a fan rotation speed
table S31 and initializing the interrupt service S32. In Step S31,
the rules for the fan rotation speed must be defined, which are
relevant to the temperature, that is, the rotation speed table is
created according to the relationship between the fan rotation
speed and the temperature. First, one or more thresholds are
defined in the rotation speed table, e.g., 27.degree. C.,
31.degree. C., and 35.degree. C. (the temperatures may also be set
by the user). According to the operating temperature sensed by the
thermo sensor 21, the rotation speed table may be set as follows:
if the operating temperature is equal to or higher than 35.degree.
C., the fan 25 is set to rotate at a full speed; if the operating
temperature is lower than 35.degree. C. but equal to or higher than
31.degree. C., the fan 25 is set to rotate at a mid speed (90% of
the full speed); if the operating temperature is lower than
31.degree. C. but equal to or higher than 27.degree. C., the fan 25
is set to rotate at a low speed (70% of the full speed); and if the
operating temperature is lower than 27.degree. C., the fan 25 is
set to rotate at a lowest speed (60% of the full speed). Next, in
Step S32, the interrupt service is initialized such that the
processing unit 23 can execute the interrupt service, once the
interrupt event is received.
[0026] Similarly, referring to FIGS. 2 and 3B, after setting the
fan rotation speed table and initializing the interrupt service,
the computer system loads the operating system. In most of the
working duration, the operating system need not process operations
relevant to temperature control so the overall performance of the
system is improved. The thermo monitor motion is taken over by the
thermo sensor 21 and the thermo monitor unit 22. The thermo sensor
21 performs Steps S33 to sense the operating temperature, and
outputs the sensed result to the thermo monitor unit 22. The thermo
monitor unit 22 performs Step S34 to compare the sensed result with
the threshold, and then performs Step S35 to decide whether or not
to send the interrupt event to the processing unit 23. For example,
if the sensed result of the thermo sensor 21 shows that the current
operating temperature is approximately equal to the threshold
(e.g., 27.degree. C., 31.degree. C., or 35.degree. C.), the system
may need to adjust the fan rotation speed according to the rotation
speed table. Therefore, the thermo monitor unit 22 sends the
interrupt event to the processing unit 23. The operation modes of
Steps S33-S35 have already been described above, and therefore will
not be repeated again.
[0027] The detailed sub-steps of the interrupt service (Step S36)
are further illustrated, which include the following three specific
sub-steps: reading the sensed result (step S36a), determining the
value of the fan rotation speed according to the fan rotation speed
table (step S36b), and outputting the speed of the fan rotation
speed (step S36c). In Step S36a, the processing unit 23 reads the
current operating temperature (i.e., the sensed result of the
thermo sensor 21). In this embodiment, the thermo monitor unit 22
monitors the sensed result of the thermo sensor 21 at any time, so
the processing unit 23 can obtain the current operating temperature
(the sensed result) from the thermo monitor unit 22. In other
embodiments, the processing unit 23 may obtain the current
operating temperature (the sensed result) directly from the thermo
sensor 21.
[0028] In Step S36b, the processing unit 23 determines the value of
the fan rotation speed by means of looking up the rotation speed
table preset in Step S31. For example, after receiving the
interrupt event sent from the thermo monitor unit 22, the
processing unit 23 reads the current operating temperature from the
thermo monitor unit 22 (or the thermo sensor 21), and then looks up
the above rotation speed table. According to the sensed result of
the thermo sensor 21, the processing unit 23 can find out the
corresponding value of the fan rotation speed from the rotation
speed table. Similarly, if the operating temperature is equal to or
higher than 35.degree. C., the corresponding value of the fan
rotation speed is 100% (full speed); if the operating temperature
falls between 35.degree. C. and 31.degree. C., the corresponding
value of the fan rotation speed is 90% (mid speed); if the
operating temperature falls between 31.degree. C. and 27.degree.
C., the corresponding value of the fan rotation speed is 70% (low
speed); and if the operating temperature is lower than 27.degree.
C., the corresponding value of the fan rotation speed is 60%
(lowest speed).
[0029] Next, in Step S36c, the processing unit 23 outputs the value
of the fan rotation speed obtained by looking up the table to the
driving unit 24. Finally, in Step S38, the driving unit 24 drives
the fan 25 and controls the rotation speed of the fan 25 according
to the value of the fan rotation speed. Once the interrupt service
in Step S36 is completed, the processing unit 23 need not process
operations relevant to temperature control any more (until the
thermo monitor unit 22 sends another interrupt event), so the
overall performance of the system is improved.
[0030] In another embodiment of the present invention, the
interrupt service may be implemented in another mode. FIG. 4 is a
flow chart of Step S36' as another implementing manner of an
interrupt service (Step S36) shown in FIG. 3B according to an
embodiment of the present invention. Referring to FIGS. 2 and 4,
the processing unit 23 similarly reads the operating temperature
obtained from the thermo sensor 21 or the thermo monitor unit 22,
in Step S36a. Next, in Step S36d, the value of the fan rotation
speed is obtained by means of looking up the fan rotation speed
table, and then the value of the fan rotation speed obtained from
the fan rotation speed table is compared with the current value of
the fan rotation speed. If the two values are the same (which
indicates that the current value of the fan rotation speed does not
need to be changed). In Step S38, the driving unit 24 drives the
fan 25 and controls the rotation speed of the fan 25 according to
the original fan rotation speed. If the two values are different
(which indicates that the current value of the fan rotation speed
needs to be changed), the processing unit 23 sets the value of the
fan rotation speed obtained from the fan rotation table as the
"current value of the fan rotation speed", in Step S36e, and then
outputs the value of the fan rotation speed, in Step S36c. Next,
the driving unit 24 drives the fan 25 and controls the rotation
speed of the fan 25 according to the newly-set fan rotation speed,
in Step S38. Thus, the fan 25 rotates at the new rotation speed to
send the wind flow, so as to reduce the temperature of the interior
of the computer system or the CPU.
[0031] In the embodiments of the present invention, the principle
for changing the rotation speed of the fan lies in the voltage
output function, which is achieved, for example, through the pulse
width modulation (PWM) mode. The so-called PWM mode converts the
output voltage to be supplied in a pulse mode, and changes the
width and number of the pulses to obtain the required voltage and
frequency. This function changes the voltage output settings
relevant to the fan rotation speed, such that the PWM function of
the hardware can provide different voltages to the fan, and thus,
the rotation speed is changed, and heat dissipation is effectively
achieved.
[0032] As for elements mentioned in the embodiments of the present
invention, the thermo sensor 21, the thermo monitor unit 22, and
the driving unit 24 may be manufactured into a single thermo chip,
or the thermo sensor 21, the thermo monitor unit 22, and the
driving unit 24 may be integrated into the processing unit 23, so
as to reduce the cost and save the space required by circuit
wiring.
[0033] To sum up, in the embodiments of the present invention, the
above functions are achieved simply by using the interrupt event
and the interrupt service of the BIOS or driver, and thus, not only
the program architecture required by the software is greatly
simplified, but the performance of the fan is also effectively
improved. Moreover, besides being applied in computer devices such
as personal computers, servers, and workstations, or CPUs, the
cooling fan device of the present invention may also be applied on
any element requiring heat dissipation within the products such as
home appliances.
[0034] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims and their equivalents.
* * * * *