Patent Publication Number: US-2013254561-A1

Title: Power supply device

Description:
BACKGROUND 
     1. Technical Field 
     The disclosure generally relates to power supply devices, and particularly to a power supply device applied to a server system. 
     2. Description of Related Art 
     Many computer systems can operate using multiple servers. For example, a 4-in-1 2U server system includes four servers sharing a hard disk backplane. Each server can control multiple hard disks using the hard disk backplane to observably increase a data processing ability of the system. Because each server commonly independently works, each server must include a corresponding independent power supply which cannot be influenced by power supplies of other servers. However, if a special power supply is configured for each server, the server system is complicated and cost of the server system is also increased. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present disclosure can be better understood with reference to the following 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  is a block diagram of a power supply device, according to an exemplary embodiment of the disclosure. 
         FIG. 2  is a circuit diagram of a control circuit of the power supply device of  FIG. 1 , according to the exemplary embodiment of the disclosure. 
         FIG. 3  is a circuit diagram of a selection circuit of the power supply device of  FIG. 1 , according to the exemplary embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of a power supply device  100 , according to an exemplary embodiment of the disclosure. The power supply device  100  is used in a computer system comprising multiple servers to provide electrical power for the servers. In this exemplary embodiment, the power supply  100  is used in a 4-in-1 2U server system. The 4-in-1 server system includes four servers A 1 -A 4 . The power supply device  100  selectively provides electrical power to some of the four servers A 1 -A 4 . 
     In  FIG. 2 , the power supply device  100  includes a first power supply  10 , a control circuit  20 , and a selection circuit  30 . The first power supply  10  may be a battery or an adapter connected to a power supply. The control circuit  20  includes four first buffers Buffer 1 -Buffer  4  corresponding to the servers A 1 -A 4 , a pull-up resistor R H  and a second buffer Buffer 5 . An input terminal of each first buffer Buffer 1 -Buffer 4  is electrically connected to one of the corresponding servers A 1 -A 4 . An output terminal of each first buffer Buffer 1 -Buffer 4  is connected together and also electrically connected to a second power supply Vcc by the pull-up resistor RH. An input terminal of the second buffer Buffer 5  is electrically connected to the output terminals of the first buffers Buffer 1 -Buffer 4 . An output terminal of the second buffer Buffer 5  is electrically connected to the first power supply  10 . 
     In one exemplary embodiment, the servers A 1 -A 4  are set as generating a preset high level voltage signal (i.e. logic 1) in a power off or standby state and generating a preset low level voltage signal (i.e. logic 0) as a power on signal when the servers A 1 -A 4  are powered on. Thus, when some of the servers A 1 -A 4  are powered on, the corresponding power on signals are generated by the powered on servers A 1 -A 4 , and then input to the corresponding first buffers Buffer 1 -Buffer 4  and the second buffer Buffer 5 , and finally output to first power supply  10  to activate the first power supply  10 . 
     In other embodiment, the second buffer Buffer 5  can be omitted, the output terminals of the first buffers Buffer 1 -Buffer 5  are directly connected to the first power supply  10 . 
     In  FIG. 3 , the selection circuit  30  includes four NOT gates U 1  corresponding to the servers A 1 -A 4 , four controllers C 1 , four sampling resistors Rf 1 -Rf 4 , and four transistors Q 1 -Q 4 . 
     An input terminal of each NOT gate U 1  is electrically connected one of the corresponding servers A 1 -A 4 . An output terminal of each NOT gate U 1  is electrically connected to one of the corresponding controllers C 1 . 
     The controllers C 1  may be an LM25066-typed integrated microchip in one embodiment. Each controller C 1  includes a power supply contact Vin, an enable contact EN, a current sensing contact SENSE, and a driving contact GATE. The power supply contact Vin is electrically connected to the first power supply  10 . The enable contact EN is electrically connected to the output terminal of one NOT gate U 1 . The current sensing contact SENSE is electrically connected to the first power supply  10  by one of the corresponding sampling resistors Rf 1 -Rf 4 . The transistors Q 1 -Q 4  are metal-oxide-semiconductor field-effect transistors (MOSFETs). A gate of each transistor Q 1 -Q 4  is electrically connected to the driving contact GATE. A source of each transistor Q 1 -Q 4  is electrically connected to one of the servers A 1 -A 4 . A drain of each transistor Q 1 -Q 4  is electrically connected to the current sensing contact SENSE of one of the controllers C 1 -C 4 . 
     According to characteristics of the controllers C 1 -C 4 , when the enable contact EN of one of the controllers C 1 -C 4  is at a high level (i.e. logic 1), the corresponding controller C 1 -C 4  is enabled. The enabled controller C 1 -C 4  outputs a turn on signal to one of the transistors Q 1 -Q 4 . The corresponding transistor Q 1 -Q 4  is turned on. Thus, one of the corresponding servers A 1 -A 4  is electrically connected to the first power supply  10  and obtains the electric power from the first power supply  10 . The current sensing contact SENSE obtains current output from the first power supply  10  by the sampling resistor Rf 1 -Rf 4 . Once the sensed current exceeds preset current, the controller C 1 -C 4  outputs a turn off signal to the transistor Q 1 -Q 4  to disconnect the server A 1 -A 4  from the first power supply  10  and protects the server A 1 -A 4  from damages due to over-current. 
     When the servers A 1 -A 4  are in the power-off state or the standby state, the high level voltages (logic 1) are input to the first buffers Buffer 1 -Buffer 4  and the second buffer Buffer 5 , and finally output to the first power supply  10 . The first power supply  10  is inactivated. 
     When at least one of the servers A 1 -A 4  is powered on, the powered on server A 1 -A 4  generates an power on signal, such as low level voltages (logic 0). The power on signals are input to the first power supply  10  by the first buffers Buffer 1 -Buffer 4  and the second buffer Buffer 5 . Thus, the first power supply  10  is activated. 
     In addition, the low level voltages generated by the powered on servers A 1 -A 4  are also input into the corresponding NOT gates. The corresponding NOT gates output the corresponding high level voltage to enable the corresponding controllers C 1 -C 4 . The enabled controllers C 1 -C 4  generates the turn on signals to turn on the corresponding transistors Q 1 -Q 4  so that the powered on servers A 1 -A 4  are electrically connected to the first power supply  10  and obtain the electric power from the first power supply  10 . Moreover, when the controllers C 1 -C 4  sense that the current output the first power supply  10  exceeds the preset current, the controller C 1 -C 4  outputs a turn off signal to the transistor Q 1 -Q 4  to disconnect the server A 1 -A 4  from the first power supply  10  to protect the server A 1 -A 4 . 
     In other embodiments, the number of the first buffers, the NOT gates, the controller and the transistors can be changed according to the number of the servers. 
     The power supply  100  can serve as a power source for the multiple servers A 1 -A 4  and selectively provide electric power to some of the servers A 1 -A 4 . Each server can be independently power supplied by the power supply  100  without a special power supply. The server system has a simple structure and costs less. 
     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.