Abstract:
A printed circuit board includes a high-speed differential signal control chip, first to eighth coupling capacitor pads, first to fourth connector pads, a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, first to eighth transmission lines, two ninth transmission lines, first and second vias, and first to fourth sharing pads. The printed circuit board is operable to selectively support multiple connectors.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to printed circuit boards (PCBs) and, particularly, to a PCB selectively supporting four different connectors. 
         [0003]    2. Description of Related Art 
         [0004]    A computer motherboard includes hard disk drive (HDD) connectors to install HDDs, such as SAS (serial attached SCSI) HDDs and SATA (serial ATA) HDDs. The SAS and SATA HDDs can use a common peripheral component interconnection (PCI) chip for transmitting data, while the motherboard normally only supports connectors of one type, such that layout of the motherboard must be changed when the HDD type is changed, which increases costs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Many aspects of the present embodiments 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 present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views. 
           [0006]      FIG. 1  is a schematic, isometric view of an embodiment of a printed circuit board (PCB). 
           [0007]      FIG. 2  is a circuit diagram of the PCB of  FIG. 1 . 
           [0008]      FIG. 3  is a schematic, isometric view of the PCB of  FIG. 1 , connected to a first connector pad. 
           [0009]      FIG. 4  is a schematic, isometric view of the PCB of  FIG. 1 , connected to a second connector pad. 
           [0010]      FIG. 5  is a schematic, isometric view of the PCB of  FIG. 1 , connected to a third connector pad. 
           [0011]      FIG. 6  is a schematic, isometric view of the PCB of  FIG. 1 , connected to a fourth connector pad. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
         [0013]    Referring to  FIGS. 1 and 2 , an embodiment of a printed circuit board (PCB)  100  includes a high-speed differential signal control chip  10 , first to eighth coupling capacitor pads  21 - 28 , first to fourth connector pads  31 - 34 , ten transmission lines  110 ,  120 ,  210 ,  220 ,  230 ,  240 ,  250 ,  260 ,  270 , and  280 , and first to fourth sharing pads  12 ,  14 ,  16 , and  18 . In one embodiment, the first and second connector pads  31  and  32 , the transmission lines  210 ,  220 ,  230 , and  240 , the first to fourth coupling capacitor pads  21 - 24 , and the first and second sharing pads  12  and  14  are arranged in a first layer of the PCB  100 . The third and fourth connector pads  33  and  34 , the transmission lines  250 ,  260 ,  270 , and  280 , the fifth to eighth coupling capacitor pads  25 - 28 , and the third and fourth sharing pads  16  and  18  are arranged in a second layer of the PCB  100  below the first layer. The transmission lines  110  and  120  are arranged in a third layer between the first layer and the second layer of the PCB  100 . The first sharing pad  12  is electrically connected to the third sharing pad  16  through a first via  13 . The second sharing pad  14  is electrically connected to the fourth sharing pad  18  through a second via  15 . The first to fourth connector pads  31 - 34  are supported for different types of connectors (not shown), respectively for a first connector, a second connector, a third connector, and a fourth connector. 
         [0014]    The chip  10  is arranged in the first layer or the second layer of the PCB  100 . First terminals of the transmission lines  110  and  120  are connected to the chip  10 , and second terminals of the transmission lines  110  and  120  are respectively connected to the first via  13  and the second via  15 . First terminals of the transmission lines  210  and  220  are connected to two input terminals of the first connector pad  31 . Second terminals of the transmission lines  210  and  220  are respectively connected to the first and second coupling capacitor pads  21  and  22 . First terminals of the transmission lines  230  and  240  are connected to two input terminals of the second connector pad  32 . Second terminals of the transmission lines  230  and  240  are respectively connected to the third and fourth coupling capacitor pads  23  and  24 . First terminals of the transmission lines  250  and  260  are connected to two input terminals of the third connector pad  33 . Second terminals of the transmission lines  250  and  260  are respectively connected to the fifth and sixth coupling capacitor pads  25  and  26 . First terminals of the transmission lines  270  and  280  are connected to two input terminals of the fourth connector pad  34 . Second terminals of the transmission lines  270  and  280  are respectively connected to the seventh and eighth coupling capacitor pads  27  and  28 . 
         [0015]    The first sharing pad  12  is arranged between the first and third coupling capacitor pads  21  and  23 . The second sharing pad  14  is arranged between the second and fourth coupling capacitor pads  22  and  24 . The third sharing pad  16  is arranged between the fifth and seventh coupling capacitor pads  25  and  27 . The fourth sharing pad  18  is arranged between the sixth and eighth coupling capacitor pads  26  and  28 . 
         [0016]    Referring to  FIG. 3 , when the first connector is installed in the first connector pad  31 , the third to eighth coupling capacitor pads  23 - 28  are void. Two coupling capacitors  200 , such as alternating current (AC) coupling capacitors, are respectively connected to the first coupling capacitor pad  21  and the first sharing pad  12 , and connected to the second coupling capacitor pad  22  and the second sharing pad  14 . A bridge capacitor  300  is connected to the third sharing pad  16  and the fourth sharing pad  18 . Thus, high-speed differential signals output by the chip  10  are transmitted to the first connector through the transmission lines  110  and  120 , the first and second vias  13  and  15 , the first and second sharing pads  12  and  14 , the coupling capacitors  200 , the first and second coupling capacitor pads  21  and  22 , and the transmission lines  210  and  220  in order. The bridge capacitor  300  can decrease signal intensity of the high-speed differential signals output by the chip  10 , to increase reliability thereof. In other embodiments, the bridge capacitor  300  can be omitted for conserving costs. 
         [0017]    Referring to  FIG. 4 , when the second connector is installed in the second connector pad  32 , the first, second, and fifth to eighth coupling capacitor pads  21 ,  22 , and  25 - 28  are void. Two coupling capacitors  200  are respectively connected to the third coupling capacitor pad  23  and the first sharing pad  12 , and connected to the fourth coupling capacitor pad  24  and the second sharing pad  14 . A bridge capacitor  300  is connected to the third sharing pad  16  and the fourth sharing pad  18 . Thus, high-speed differential signals output by the chip  10  are transmitted to the second connector through the transmission lines  110  and  120 , the first and second vias  13  and  15 , the first and second sharing pads  12  and  14 , the coupling capacitors  200 , the third and fourth coupling capacitor pads  23  and  24 , and the transmission lines  230  and  240  in order. 
         [0018]    Referring to  FIG. 5 , when the third connector is installed in the third connector pad  33 , the first to fourth, seventh, and eighth coupling capacitor pads  21 - 24 ,  27 , and  28  are void. Two coupling capacitors  200  are respectively connected to the fifth coupling capacitor pad  25  and the third sharing pad  16 , and connected to the sixth coupling capacitor pad  26  and the fourth sharing pad  18 . A bridge capacitor  300  is connected to the first sharing pad  12  and the second sharing pad  14 . Thus, high-speed differential signals output by the chip  10  are transmitted to the third connector through the transmission lines  110  and  120 , the first and second vias  13  and  15 , the third and fourth sharing pads  16  and  18 , the coupling capacitors  200 , the fifth and sixth coupling capacitor pads  25  and  26 , and the transmission lines  250  and  260  in order. 
         [0019]    Referring to  FIG. 6 , when the fourth connector is installed in the fourth connector pad  34 , the first to sixth coupling capacitor pads  21 - 26  are void. Two coupling capacitors  200  are respectively connected to the seventh coupling capacitor pad  27  and the third sharing pad  16 , and connected to the eighth coupling capacitor pad  28  and the fourth sharing pad  18 . A bridge capacitor  300  is connected to the first sharing pad  12  and the second sharing pad  14 . Thus, high-speed differential signals output by the chip  10  are transmitted to the fourth connector through the transmission lines  110  and  120 , the first and second vias  13  and  15 , the third and fourth sharing pads  16  and  18 , the coupling capacitors  200 , the seventh and eighth coupling capacitor pads  27  and  28 , and the transmission lines  270  and  280  in order. 
         [0020]    Thus, the PCB  100  is capable of flexibly supporting different types of connectors according to requirements, to decrease cost. 
         [0021]    It is to be understood, however, that even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.