Patent Publication Number: US-2013229765-A1

Title: Temperature control device for hard disk drive of server system

Description:
BACKGROUND 
     1. Technical Field 
     The exemplary disclosure generally server systems, and particularly to a temperature control device for hard disk drives of a server system. 
     2. Description of Related Art 
     A 1U server system may include eight hard disk drives sharing a hard disk backboard in a 1U chassis. The sever system further includes a fan device to dissipate heat generated by the hard disk drives. Rotational speed of the whole fan device is increased to speed up the dissipation of heat when temperature of even one or two hard disk drives is increased, which will use more power and increase electricity costs. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments can be better understood with reference to the drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. 
         FIG. 1  shows a block diagram of an exemplary embodiment of a server system comprising a temperature control device for hard disk drives. 
         FIG. 2  shows an exemplary circuit diagram of a temperature sensing group of the temperature control device shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a block diagram of an exemplary embodiment of a server system  100  comprising a temperature control device for hard disk drives. The server system  100  includes a hard disk backboard  10 , the temperature control device, and a plurality of hard disk drives electronically connected to the backboard  10 . In the exemplary embodiment, the server system  100  includes eight hard disk drives HDD 0 -HDD 7 , but the disclosure is not limited thereto. The temperature control device includes a temperature sensing group  20 , a fan group, and a controller  30 . 
       FIG. 2  shows an exemplary circuit diagram of the temperature sensing group  20  of the temperature control device shown in  FIG. 1 . Each hard disk drive includes a gold finger connecting the hard disk drive to the backboard  10 . Since the gold fingers are electronically connected to the backboard  10  in a method well known in the art, the connection circuits between the gold fingers and the backboard  10  are not shown in  FIGS. 1 and 2 . Each gold finger includes a group of unused power pins. For example, the hard disk drive HDD 0  includes a gold finger J 0  including a group of unused power pins V 33 - 1  and V 33 - 2 ; and the hard disk drive HDD 7  includes a gold finger J 7  including a group of unused power pins V 33 - 1  and V 33 - 2 . The temperature sensing group  20  includes eight sensing modules arranged corresponding to the hard disk drives HDD 0 -HDD 7  respectively. The first and the eighth sensing modules are labeled  21  and  28  respectively in  FIGS. 1 and 2 , and the second to seventh sensing modules are not labeled. Each sensing module is disposed adjacent to the corresponding hard disk drive, to detect temperature of the corresponding hard disk drive. For example, the first sensing module  21  is disposed adjacent to the hard disk drive HDD 0 , to detect temperature of the hard disk drive HDD 0 . Each sensing module includes a switch, and a sensor electronically connected to the switch and a gold finger of a corresponding hard disk drive. The sensor detects the temperature of the corresponding hard disk drive, numbers the corresponding hard disk drive in conjunction with the switch, and outputs the temperature and a number signal to the backboard  10  via the gold finger. 
     For example, the first sensing module  21  includes a switch  211  and a sensor  212 . The switch  211  includes six (first to sixth) terminals S 1 -S 6 . Each two of the six terminals cooperate to form a sub-switch, and each sub-switch can be switched by a button (not shown). For example, the first and the sixth terminals S 1  and S 6  cooperate to form a first sub-switch SW 1 ; the second and the fifth terminals S 2  and S 5  cooperate to form a second sub-switch SW 2 , and the third and the fourth terminals S 3  and S 4  cooperate to form a third sub-switch SW 3 . 
     In the embodiment, the sensor  212  can be a TMP57 temperature sensor made by TEXAS INSTRUMENTS. The sensor  212  includes a power pin VCC, a data pin SDA, a clock pin SCL, a ground pin GND, and three address pins A 0 -A 2 . The power pin VCC is electronically connected to a power supply P 5 V. The data pin SDA and the clock pin SCL are electronically connected the power pins V 33 - 1  and V 33 - 2  of the gold finger J 0  respectively. The ground pin GND is grounded. Each address pin is electronically connected to one terminal of a corresponding sub-switch via a pull-down resistor, and is electronically connected to the power supply P 5 V via a pull-up resistor. 
     The other terminal of each sub-switch is grounded. For example, the address pins A 0 -A 2  are electronically connected to terminals S 6 , S 5  and S 4  of the sub-switches SW 1 -SW 3  via pull-down resistors R 4 -R 6  respectively, and are electronically connected to the power supply P 5 V via pull-up resistors R 1 -R 3  respectively. 
     In the exemplary embodiment, the buttons of the switch  211  is operated to make all of the sub-switches SW 1 -SW 3  to switch on. At this time, the address pins A 0 -A 2  of the sensor  212  are grounded via the sub-switches SW 1 -SW 3  respectively, and a voltage level of each address pin is low level (logic 0). Therefore, the sensor  212  generates a number signal “0,0,0” denoting the hard disk drive HDD0, and outputs the number signal “0,0,0” and the temperature of the hard disk drive HDD 0  to the backboard  10  via the unused power pins V 33 - 1  and V 33 - 2 . 
     The second to the eighth sending modules have the same circuit construction as a circuit construction of the first sending module  21 . The switches of the second to eighth sensing modules are operated to make sensors of the second to eighth sensing modules to output number signals “0,0,1”, “0,1,0”, “0,1,1”, “1,0,0”, “1,0,1”, “1,1,0”, “1,1,1”, respectively. The number signals “0,0,1”, “0,1,0”, “0,1,1”, “1,0,0”, “1,0,1”, “1,1,0”, “1,1,1” corresponding to the hard disk drives HDD 1 -HDD 7  respectively. The sensors of the second to eighth sensing modules output the number signals and temperatures of corresponding hard disk drive to the backboard  10  via the corresponding gold finger. 
     The fan group includes four fans. Each fan facing two of the hard disk drives, to dissipate heat generated by the two hard disk drives. For example, the fan group includes a first fan FAN 1 , a second fan FAN 2 , a third fan FAN 3 , and a fourth fan FAN 4 . The first fan FAN 1  facing the hard disk drives HDD 0  and HDD 1 . The second fan FAN 2  facing the hard disk drives HDD 2  and HDD 3 . The third fan FAN 3  facing the hard disk drives HDD 4  and HDD 5 . The fourth fan FAN 4  facing the hard disk drives HDD 6  and HDD 7 . 
     The controller  30  controls rotational speed of the fans FAN 1 -FAN 4  according to the number signals and the temperatures detected by the sensors. In one embodiment, the controller  30  can be a baseboard management controller (BMC). The controller  30  includes a system management bus connector SMBus, and four pulse width modulation pin PWM 1 -PWM 4 . The system management bus connector SMBus is electronically connected to the backboard  10  via I2C bus, thereby connecting the controller  30  to the backboard  10 , to allow the controller  30  to receive temperatures and number signals from the temperature sensing group  20 . The pulse width modulation pins PWM 1 -PWM 4  are electronically connected to the fans FAN 1 -FAN 4  respectively. 
     In use, each sensor of the temperature sensing group  20  detects the temperature of corresponding hard disk drive, and outputs the temperature and the number signals to the controller  30  via the backboard  10  and the system management bus connector SMBus. The controller  30  finds a corresponding fan according to the number signal of each hard disk drive, and regulates the rotational speed of the corresponding fan according to the temperature of the hard disk drive. In the exemplary embodiment, the controller  30  compares the temperature of each hard disk drive to a predetermined temperature, the controller  30  increases the rotational speed of the corresponding fan when the temperature of one of the hard disk drive is higher than the predetermined temperature, and decreases the rotational speed of the corresponding fan after the temperature of one of the hard disk drive is lower than the predetermined temperature. 
     Thus, the rotational speed of the fans can be controlled by the controller  30  separately, according to the temperature of corresponding hard disk drive, which will reduce power use. 
     It is believed that the exemplary embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the disclosure.