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.

Description

CROSS-REFERENCE TO RELATED APPLICATION

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

1. Field of the Invention

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.

2. Description of Related Art

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.

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_MIN, the fan operates at a minimum output power P_MIN; when the temperature is higher than a preset maximum temperature T_MAX, the fan operates at a maximum output power P_MAX; when the temperature falls between T_MIN and T_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_MIN and T_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

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.

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.

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.

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.

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.

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.

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

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.

FIG. 1 is a power-temperature curve diagram of a conventional method of automatically controlling a fan rotation method.

FIG. 2 is a structural view of a fan cooling device according to an embodiment of the present invention.

FIG. 3A is a flow chart of controlling a fan rotation speed according to an embodiment of the present invention.

FIG. 3B is a detailed flow chart of controlling a fan rotation speed according to an embodiment of the present invention.

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

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.

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.

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.

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.

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.

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° C., 31° C., and 35° 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° C., the fan 25 is set to rotate at a full speed; if the operating temperature is lower than 35° C. but equal to or higher than 31° 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° C. but equal to or higher than 27° 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° 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.

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° C., 31° C., or 35° 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.

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.

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° C., the corresponding value of the fan rotation speed is 100% (full speed); if the operating temperature falls between 35° C. and 31° C., the corresponding value of the fan rotation speed is 90% (mid speed); if the operating temperature falls between 31° C. and 27° C., the corresponding value of the fan rotation speed is 70% (low speed); and if the operating temperature is lower than 27° C., the corresponding value of the fan rotation speed is 60% (lowest speed).

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.

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.

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.

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.

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.

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.

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.