Printed circuit board

1. Technical Field

The present disclosure relates to a printed circuit board (PCB).

2. Description of Related Art

PCBs can be found in most electronic devices and must be able to support transmission of high-speed differential signals. If high-speed differential signals are transmitted to at least three electronic elements, laying out signal lines of the PCBs becomes overly complicated and may lead to design flaws affecting performance of the PCBs.

Many aspects of the 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, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic diagram of an exemplary embodiment of a printed circuit board connected to a first electronic element.

FIG. 2 is similar to FIG. 1 , but showing a second electronic element connected.

FIG. 3 is similar to FIG. 1 , but showing a third electronic element connected.

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.

Referring to FIG. 1 , an exemplary embodiment of a printed circuit board (PCB) 100 includes a first signal layer 10 , a second signal layer 20 , an insulation layer (omitted to provide clear view of connections between layers 10 and 20 ) located between the first and second signal layers 10 and 20 , a pair of first vias 40 A and 40 B, a pair of second vias 41 A and 41 B, and a control chip 4 . The first vias 40 A and 40 B, and the second vias 41 A and 41 B extend through the first signal layer 10 , the insulation layer, and the second signal layer 20 .

A pair of first bonding pads 11 A and 11 B and a pair of second bonding pads 12 A and 12 B are mounted on the first signal layer 10 , and electrically connected to the pair of first vias 40 A and 40 B, and the pair of second vias 41 A and 41 B. The second bonding pads 12 A and 12 B are connected to a first electronic element 1 . The first bonding pads 11 A and 11 B are connected to a second electronic element 2 .

A pair of third bonding pads 23 A and 23 B, a pair of fourth bonding pads 24 A and 24 B, a pair of fifth bonding pads 25 A and 25 B, a pair of sixth bonding pads 26 A and 26 B, a pair of seventh bonding pad 27 A and 27 B, and a pair of eighth bonding pads 28 A and 28 B are mounted on the second signal layer 20 . The fourth bonding pads 24 A and 24 B are mounted between the third bonding pads 23 A and 23 B and the fifth bonding pads 25 A and 25 B. The third bonding pads 23 A and 23 B are connected to the second bonding pads 12 A and 12 B by the second vias 41 A and 41 B. The seventh bonding pads 27 A and 27 B are mounted between the sixth bonding pads 26 A and 26 B and the eighth bonding pads 28 A and 28 B. The seventh bonding pads 27 A and 27 B are connected to the fifth bonding pads 25 A and 25 B. The sixth bonding pads 26 A and 26 B are connected to the first bonding pads 11 A and 11 B by the first vias 40 A and 40 B. The fourth bonding pads 24 A and 24 B are connected to the control chip 4 for transmission of a pair of high-speed signals therethrough such as a pair of differential signals from the control chip 4 . The eighth bonding pads 28 A and 28 B are connected to a third electronic element 3 .

When the control chip 4 transmits the pair of high speed signals to the first electronic element 1 , a first passive element 21 is used to connect the third bonding pads 23 A to the fourth bonding pad 24 A. A second passive element 22 is used to connect the third bonding pads 23 B to the fourth bonding pad 24 B. The control chip 4 outputs the pair of high-speed signals to the first electronic element 1 through the fourth bonding pads 24 A and 24 B, the first and second passive elements 21 and 22 , the third bonding pads 23 A and 23 B, the second vias 41 A and 41 B, and the second bonding pads 12 A and 12 B.

Referring to FIG. 2 , when the control chip 4 transmits the pair of high-speed signals to the second electronic element 2 , the first passive element 21 is used to connect the fourth bonding pads 24 A to the fifth bonding pad 25 A. The second passive element 22 is used to connect the fourth bonding pad 24 B and to the fifth bonding pad 25 B. A third passive element 31 is used to connect the sixth bonding pads 26 A to the seventh bonding pad 27 A. A fourth passive element 32 is used to connect the sixth bonding pads 26 B to the seventh bonding pad 27 B. The control chip 4 outputs the pair of high-speed signals to the second electronic element 2 through the fourth bonding pads 24 A and 24 B, the first and second passive elements 21 and 22 , the fifth bonding pads 25 A and 25 B, the seventh bonding pads 27 A and 27 B, the third and fourth passive elements 31 and 32 , the sixth bonding pads 26 A and 26 B, the first vias 40 A and 40 B, and the first bonding pads 11 A and 11 B.

Referring to FIG. 3 , when the control chip 4 transmits the pair of high-speed signals to the third electronic element 3 , the first passive element 21 is used to connect the fourth bonding pads 24 A to the fifth bonding pad 25 A. The second passive element 22 is used to connect the fourth bonding pads 24 B to the fifth bonding pad 25 B. The third passive element 31 is used to connect the seventh bonding pads 27 A to the eighth bonding pad 28 A. The fourth passive element 32 is used to connect the seventh bonding pads 27 B to the eighth bonding pad 28 B. The control chip 4 outputs the pair of high-speed signals to the third electronic element 3 through the fourth bonding pads 24 A and 24 B, the first and second passive elements 21 and 22 , the fifth bonding pads 25 A and 25 B, the seventh bonding pads 27 A and 27 B, the third and fourth passive elements 31 and 32 , and the eighth bonding pads 28 A and 28 B. In the embodiment, the first passive element 21 aligns with the second passive element 22 . The third passive element 31 aligns with the fourth passive element 32 . The first to fourth passive elements 21 , 22 , 31 , and 32 may be resistors.

It is to be understood, however, that even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, 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 disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.