Patent Publication Number: US-2021164482-A1

Title: Fan control system and method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan Application Serial No. 108143981, filed on Dec. 2, 2019. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The disclosure relates to a control system, and in particular, to a fan control system and the method thereof. 
     Description of the Related Art 
     As electronic devices are increasingly developed, heat dissipation modes as well as the mechanisms that use fans to control heat dissipation become increasingly complex. 
     BRIEF SUMMARY OF THE INVENTION 
     The disclosure provides a fan control system, including a fan, a first temperature sensor, a calculating unit, a logic controller, and a memory unit. The first temperature sensor continuously senses temperatures of a device during a time period, in order to obtain a plurality of sampled temperatures. The calculating unit selects N 1  latest sampled temperatures and N 2  latest sampled temperatures from the sampled temperatures, and calculates a first average temperature according to the N 1  sampled temperatures and a second average temperature according to the N 2  sampled temperatures. N 1  and N 2  are positive integers. The logic controller is configured to select one of the first average temperature and the second average temperature to output as a compensation temperature. The memory unit is configured to store an operating table, and configured to output a rotational speed control signal to the fan corresponding to the operating table according to the compensation temperature. 
     The disclosure further provides a fan control method, including the following steps: continuously sensing temperatures of a device during a time period, in order to obtain a plurality of sampled temperatures; selecting N 1  latest sampled temperatures and N 2  latest sampled temperatures from the sampled temperatures, and calculating a first average temperature according to the N 1  sampled temperatures and a second average temperature according to the N 2  sampled temperatures, where N 1  and N 2  are positive integers; selecting one of the first average temperature and the second average temperature according to a control signal to output as a compensation temperature; and adjusting a rotational speed of a fan according to the compensation temperature. 
     Based on the foregoing, in the disclosure, the calculating unit and the logic controller are used to correct and compensate for the sampled temperatures, so that the fan control system adjusts the rotational speed of the fan according to the single operating table in a plurality of different operating modes. In this way, space of storing operating tables for different operating modes is saved, and costs of the fan control system is reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure may be more fully understood by reading the following detailed description of the embodiments, and the accompanying drawings are as follows: 
         FIG. 1  is a schematic diagram of a fan control system according to some embodiments of the disclosure; 
         FIG. 2  is a flowchart of a fan control method according to some embodiments of the disclosure; and 
         FIG. 3  is a schematic diagram of a fan control system according to some other embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The following makes detailed description by listing embodiments and with reference to the accompanying drawings, but the specific described embodiments are merely used to explain the embodiments of the disclosure, and are not intended to limit the embodiments of the disclosure. However, the description of structural operations is not intended to limit sequences in which the operations are performed, any structure in which elements are recombined and any device having equivalent functions shall fall within the scope covered by the content of the embodiments of the disclosure. 
     The term “coupled” or “connected” used in the specification may mean that two or more elements are in direct physical or electrical contact with each other or indirect physical or electrical contact with each other or two or more elements are in operation or action with each other. 
       FIG. 1  is a schematic diagram of a fan control system  100  according to some embodiments of the disclosure. In some embodiments, the fan control system  100  is configured to adjust the temperature of a heat generation device, so that the temperature in the system is appropriate for operations of the device. 
     As shown in  FIG. 1 , the fan control system  100  includes a fan  101 , a device  102 , a temperature sensor  103 , a calculating unit  104 , a logic controller  105 , a memory unit  106 , a processor  107 , an input/output interface  108 , and a temperature sensor  109 . The temperature sensor  103  is coupled to the calculating unit  104 . The calculating unit  104  is coupled to the logic controller  105 . The logic controller  105  is coupled to the memory unit  106 . The memory unit  106  is coupled to the fan  101 . The logic controller  105  is further separately coupled to the processor  107 , the input/output interface  108 , and the temperature sensor  109 . 
     In some embodiments, the fan  101  is disposed near the device  102  to generate an air flow to adjust the temperature of the device  102 . 
     In some embodiments, the device  102  is the heat generation device of which the temperature rises as a workload increases. When the air flow generated by the fan  101  flows near the device  102 , the temperature of the device  102  decreases as the air flow carries away heat. In some embodiments, the device  102  is a central processing unit (CPU). In some other embodiments, the device  102  is a graphics processing unit (GPU). 
     In some embodiments, the temperature sensor  103  is disposed near the device  102 , and is configured to sense the temperatures of the device  102 . When the temperature of the device  102  increases as the workload increases, the temperature sensed by the temperature sensor  103  increases. In some embodiments, the temperature sensor  103  is further configured to continuously sense and continuously sample the temperatures of the device  102  in a time period, in order to obtain a plurality of sampled temperatures t, and transmit the sampled temperatures t to the calculating unit  104 . 
     In some embodiments, the calculating unit  104  is configured to calculate an average value of the sampled temperatures t. The calculating unit  104  selects N 1  latest sampled temperatures and N 2  latest sampled temperatures from the sampled temperatures t, and performs calculation according to N 1  and N 2  separately. The calculating unit  104  calculates an average of the N 1  latest sampled temperatures of the sampled temperatures t as a first average temperature T 1   avg,  and calculates an average of the N 2  latest sampled temperatures of the sampled temperatures t as a second average temperature T 2   avg.  The calculating unit  104  is further configured to transmit the first average temperature T 1   avg  and the second average temperature T 2   avg  to the logic controller  105 . 
     In some embodiments, N 1  and N 2  are positive integers. N 1  is greater than 0, and N 2  is greater than N 1 . In other words, when the calculating unit  104  calculates the first average temperature T 1   avg  and the second average temperature T 2   avg,  the N 1  latest sampled temperatures of the sampled temperatures t partially overlap the N 2  latest sampled temperatures of the sampled temperatures t. 
     In an embodiment, at a moment, the temperature sensor  103  has sampled  100  temperatures t. When N 1  is equal to 10 and N 2  is equal to 50, the first average temperature T 1   avg  is an average value of the 10 latest sampled temperatures t of the 100 sampled temperatures, and the second average temperature T 2   avg  is an average value of the 50 latest sampled temperatures t of the 100 sampled temperatures. 
     In other words, it is assumed that the temperature sensor  103  has sampled the 100 sampled temperatures t 1  to t 100  in a time period, and the sampled temperatures t 100  is the latest sampled temperature of the sampled temperatures. When N 1  is equal to 10 and N 2  is equal to 50, the first average temperature T 1   avg  is an average value of sampled temperatures t 91  to t 100 , and the second average temperature T 2   avg  is an average value of sampled temperatures t 51  to t 100 . 
     In some embodiments, the logic controller  105  is configured to select one of the first average temperature T 1   avg  and the second average temperature T 2   avg  to output as a compensation temperature T and transmit the compensation temperature T to the memory unit  106 . As shown in  FIG. 1 , the memory unit  106  includes an operating table  106   a.  The operating table  106   a  has information about a relationship between a temperature and a rotational speed of a fan. The memory unit  106  outputs a rotational speed control signal Sr to the fan  101  corresponding to the operating table  106   a  according to the compensation temperature T to adjust a rotational speed of the fan  101 . In some embodiments, when the compensation temperature T is higher, the rotational speed of the fan  101  corresponding to the rotational speed control signal Sr output by the memory unit  106  is faster. 
     In some embodiments, the logic controller  105  has a plurality of determination modes, and selects one of the first average temperature T 1   avg  and the second average temperature T 2   avg  according to the determination modes. In some embodiments, the determination mode includes: (a) selecting the first average temperature T 1   avg,  (b) selecting the second average temperature T 2   avg,  (c) selecting a larger one of the first average temperature T 1   avg  and the second average temperature T 2   avg,  and (d) selecting a smaller one of the first average temperature T 1   avg  and the second average temperature T 2   avg.    
     In the determination mode (a), the logic controller  105  selects the first average temperature T 1   avg  to output as the compensation temperature T. In the determination mode (b), the logic controller  105  selects the second average temperature T 2   avg  to output as the compensation temperature T. Compared with the two modes, N 1  is less than N 2 . Therefore, it can be learned that a quantity of sampled temperatures t is smaller, and consequently, the compensation temperature T selected by the determination mode (a) is more timely than the compensation temperature T selected by the determination mode (b). Compared with the determination mode (b), in the determination mode (a), the rotational speed control signal Sr output by the memory unit  106  enables the fan  101  to be quickly adjusted corresponding to the temperature of the device  102 . 
     In some embodiments, when the rotational speed of the fan  101  is quickly adjusted, the temperature of the device  102  is also quickly adjusted, so that the temperature of the device  102  is maintained at an appropriate operating temperature, and consequently the efficiency is relatively high. In addition, because the rotational speed of the fan  101  is quickly adjusted, sound caused by the revolution of the fan  101  also changes quickly. 
     In some embodiments, when the rotational speed of the fan  101  is adjusted at a relatively slow speed, the temperature of the device  102  is also adjusted at a relatively slow speed, so that the sound caused by the fan  101  changes at a relatively slow speed. 
     In the determination mode (c), the logic controller  105  selects the larger one of the first average temperature T 1   avg  and the second average temperature T 2   avg  to output as the compensation temperature T. In this mode, when the temperatures of the device  102  quickly increase, the rotational speed of the fan  101  also quickly increases. Next, when the temperature of the device  102  decreases, the rotational speed of the fan  101  is still maintained at a relatively high rotational speed and does not quickly decrease in time, and eventually slows down. 
     Therefore, in the determination mode (c), the fan  101  has a function of adjusting the temperature of the device  102 , and also has an effect of performing continuous heat dissipation for a high temperature that remains in the system after the temperature of the device  102  decreases. In an embodiment, when the temperature of the device  102  instantaneously increases, the first average temperature T 1   avg  is higher than the second average temperature T 2   avg.  The logic controller  105  selects the first average temperature T 1   avg  to output as the compensation temperature T, so that the fan  101  has a relatively high rotational speed. Next, when the temperature of the device  102  starts to decrease, the first average temperature T 1   avg  decreases, but the second average temperature T 2   avg  is kept at a high temperature. The logic controller  105  selects the second average temperature T 2   avg  to output as the compensation temperature T, so that the fan  101  is kept at a relatively high rotational speed, and continuously enables the air flow to carry away remaining heat in the system. 
     In the determination mode (d), the logic controller  105  selects the smaller one of the first average temperature T 1   avg  and the second average temperature T 2   avg  to output as the compensation temperature T. In this mode, when the temperature of the device  102  quickly increases, the rotational speed of the fan  101  slowly increases instead of quickly increasing. When the temperature of the device  102  decreases, the rotational speed of the fan  101  quickly decreases. 
     Therefore, in the determination mode (d), the fan  101  has a time for reducing the generation of a large amount of sound change. In an embodiment, when the temperature of the device  102  instantaneously increases, the second average temperature T 2   avg  is less than the first average temperature T 1   avg.  The logic controller  105  selects the second average temperature T 2   avg  to output as the compensation temperature T, so that the rotational speed of the fan  101  does not quickly increase. Next, when the temperature of the device  102  starts to decrease slowly, the first average temperature T 1   avg  decreases, but the second average temperature T 2   avg  is kept at a high temperature. The logic controller  105  selects the first average temperature T 1   avg  to output as the compensation temperature T, so that the rotational speed of the fan  101  quickly decreases to reduce the time for reducing the generation of sound change. 
     In some embodiments, the processor  107  is configured to generate a control signal Sc 1  to the logic controller  105 . The logic controller  105  determines the determination modes according to the control signal Sc 1 , to select one of the first average temperature T 1   avg  and the second average temperature T 2   avg.    
     In some embodiments, the input/output interface  108  is configured to transmit a control signal Sc 2  external to the system to the logic controller  105 . The logic controller  105  determines a determination mode according to the control signal Sc 2 , to select one of the first average temperature T 1   avg  and the second average temperature T 2   avg.  In some embodiments, a user may customize a determination mode and transmit the control signal Sc 2  to the logic controller  105  through the input/output interface  108 . 
     In some embodiments, the temperature sensor  109  is configured to sense an ambient temperature Tab, and transmit the ambient temperature Tab to the logic controller  105 . The logic controller  105  determines a determination mode according to the ambient temperature Tab, to select one of the first average temperature T 1   avg  and the second average temperature T 2   avg.    
     In some other embodiments, the logic controller  105  is configured to adjust N 1  and N 2  according to at least one of the control signal Sc 1 , the control signal Sc 2 , and the ambient temperature Tab. In an embodiment, when the ambient temperature Tab increases, the heat dissipation capability of the fan control system  100  decreases. Therefore, the logic controller  105  is configured to reduce N 1  and N 2 , so that the rotational speed of the fan  101  changes in time, thereby improving the heat dissipation capability of the fan control system  100 . 
     In some embodiments, the memory unit  106  includes a single temperature and rotational speed comparison table, that is, the operating table  106   a.  Regardless of a determination mode in which the logic controller  105  selects the first average temperature T 1   avg  or the second average temperature T 2   avg,  the logic controller  106  only needs to output the rotational speed control signal Sr corresponding to the compensation temperature T output by the logic controller  105 . In some implementations, a heat dissipation system includes a plurality of rotational speed comparison tables, and each rotational speed comparison table corresponds to different working modes of the system. Therefore, a large amount of space is required to store the rotational speed comparison tables. 
     Compared with the foregoing implementations, in the embodiments of the disclosure, the fan control system  100  only includes the single operating table  106   a.  In different working modes, the calculating unit  104  and the logic controller  105  output the single compensation temperature T to the memory unit  106  after the sampled temperatures are appropriately corrected and compensated for. Therefore, even in different working modes, the fan control system  100  uses the single operating table  106   a  to complete different heat dissipation functions. Therefore, space of storing a plurality of operating tables for different operating modes is saved, and the cost of the fan control system  100  is reduced. 
     The arrangement of the fan control system  100  is only used for description. The arrangement of different fan control systems  100  falls within the consideration and the scope of the disclosure. 
     In some other embodiments, the fan control system  100  is a system configured to dissipate heat in a computer. The calculating unit  104 , the logic controller  105 , and the memory unit  06  are disposed in firmware such as an embedded controller (EC) in the computer. The processor  107  and the input/output interface  108  are connected to the logic controller  105  by a basic input/output system (BIOS) in the computer. 
       FIG. 2  is a flowchart of a fan control method  200  according to some embodiments of the disclosure. To better understand the content of the disclosure,  FIG. 2  is discussed with reference to element and reference numerals in  FIG. 1 . 
     As shown in  FIG. 2 , the fan control method  200  includes steps S 201 , S 202 , S 203 , S 204 , and S 205 . 
     Step S 201 : The temperature sensor  103  continuously senses temperatures of the device  102  during a time period, in order to obtain a plurality of sampled temperatures t. 
     Step S 202 : The calculating unit  104  selects N 1  latest sampled temperatures and N 2  latest sampled temperatures from the sampled temperatures t, and calculates a first average temperature T 1   avg  according to the N 1  sampled temperatures and a second average temperature T 2   avg  according to the N 2  sampled temperatures. The first average temperature T 1   avg  is an average value of the N 1  latest sampled temperatures t of all the sampled temperatures t, and the second average temperature T 2   avg  is an average value of the N 2  latest sampled temperatures t of all the sampled temperatures t. 
     Step S 203 : The logic controller  105  selects one of the first average temperature T 1   avg  and the second average temperature T 2   avg  to output as a compensation temperature T and transmits the compensation temperature T to the memory unit  106 . In some embodiments, the logic controller  105  further determines a determination mode according to at least one of the control signal Sc 1  generated by the processor  107 , the control signal Sc 2  transmitted by the input/output interface  108 , and the ambient temperature Tab sensed by the temperature sensor  109 , to select one of the first average temperature T 1   avg  and the second average temperature T 2   avg  to output as the compensation temperature T. In some embodiments, step S 203  further includes adjusting, by the logic controller  105 , N 1  and N 2  according to the ambient temperature Tab. 
     Step S 204 : Output the rotational speed control signal Sr to the fan  101  according to the operating table  106   a  in the memory unit  106  and the compensation temperature T. The rotational speed control signal Sr enables the fan  101  to have a rotational speed corresponding to the compensation temperature T. 
     Step S 205 : The fan  101  adjusts a rotational speed according to the rotational speed control signal Sr to adjust and control the temperature of the device  102 . 
     Descriptions of the fan control method  200  include exemplary steps, but the step sequence of the fan control method  200  is adjustable. That is, the sequence of the steps of the fan control method  200  is able to be changed in appropriate cases, the steps are performed simultaneously or some of the steps are performed simultaneously or omitted, which shall fall within the spirit and scope of the embodiments of the disclosure. 
       FIG. 3  is a schematic diagram of a fan control system  300  according to some other embodiments of the disclosure. Compared with the fan control system  100  shown in  FIG. 1 , the fan control system  300  includes a plurality of fans, a plurality of devices, and a plurality of temperature sensors sensing temperatures of a device. 
     As shown in  FIG. 3 , the fan control system  300  includes fans  301   a,    301   b,  devices  302   a,    302   b,    302   c,  temperature sensors  303   a,    303   b,    303   c,  a calculating unit  304 , a logic controller  305 , a memory unit  306 , a processor  307 , an input/output interface  308 , and a temperature sensor  309 . 
     The temperature sensors  303   a,    303   b,    303   c  are separately coupled to the calculating unit  304 . The calculating unit  304  is coupled to the logic controller  305 . The logic controller  305  is coupled to the memory unit  306 . The memory unit  306  is coupled to the fans  301   a,    301   b.  The logic controller  305  is further separately coupled to the processor  307 , the input/output interface  308 , and the temperature sensor  309 . 
     In some embodiments, the fans  301   a,    301   b  are disposed near the devices  302   a,    302   b,    302   c  to generate air flows to adjust the temperatures of the device  302   a,    302   b,    302   c.    
     In some embodiments, the temperature sensors  303   a,    303   b,    303   c  are configured to sense the temperatures of the devices  302   a,    302   b,    302   c  respectively. When the temperatures of the devices  302   a,    302   b,    302   c  increase as the workload increases, the temperatures sensed by the temperature sensors  303   a,    303   b,    303   c  increase. In some embodiments, the temperature sensors  303   a,    303   b,    303   c  are further configured to sense and sample the temperatures of the devices  302   a,    302   b,    302   c  and transmit the sampled temperatures t 1 , t 2 , and t 3  to the calculating unit  304 . 
     In some embodiments, different elements include similar functions, such as the calculating unit  304  and the calculating unit  104 , the logic controller  305  and the logic controller  105 , the memory unit  306  and the memory unit  106 , the operating table  306   a  and the operating table  106   a,  the processor  307  and the processor  107 , the input/output interface  308  and the input/output interface  108 , and the temperature sensor  309  and the temperature sensor. Details are not described herein again. 
     In some embodiments, when one of the fan  301   a  and the fan  301   b  fails, the heat dissipation capability of the fan control system  300  decreases. Therefore, the logic controller  305  reduces N 1  and N 2  to improve the heat dissipation capability of the fan control system  300 , so that the rotational speed of a non-failed fan changes in time for responding to the temperatures of the devices  302   a  to  302   c.  When an abnormal fan is recovered, the heat dissipation capability of the fan control system  300  improves, so that the rotational speed of the fan responses to the temperatures of the devices  302   a  to  302   c  in time, and the logic controller  305  increases N 1  and N 2 . 
     Quantities of the fans  301   a  and  301   b,  the devices  302   a  to  302   c,  and the temperature sensors  303   a  to  303   c  in the fan control system  300  are merely used for description. Different quantities of the fans, the devices, and the temperature sensors are all within the spirit and scope of the embodiments disclosed in the disclosure. 
     Based on the foregoing, in the disclosure, the calculating unit and the logic controller are used to correct and compensate for the sampled temperatures, so that the fan control system adjusts the rotational speed of the fan according to the single operating table in a plurality of different operating modes. In this way, space of storing operating tables for different operating modes is saved, and costs of the fan control system is reduced. 
     Although the embodiments of the disclosure have been disclosed above, the embodiments are not intended to limit the embodiments of the disclosure. A person skilled in the art may make variations and modifications without departing from the spirit and scope of the embodiments of the disclosure. Therefore, the protection scope of the embodiments of the disclosure should be subject to the appended claims.