Circuit board with higher current

1. Technical Field

The disclosure generally relates to circuit boards, and particularly to a multilayer circuit board with an even current distribution and relatively higher current transmission efficiency.

2. Description of Related Art

A typical circuit board usually includes a plurality of conductive layers made of copper foil and a plurality of vias defined in the conductive layer to electrically connect the conductive layers. A voltage regulator module can provide electrically power to the circuit board by a plurality of power supply elements such as output choke coils. The power supply elements outputs current to an electronic element, such as a processor mounted to the circuit board by the vias and the conductive layers.

However, when the distribution of the vias arranged on the circuit board is irregular, current flowing through each via is different, which causes the current distribution of the circuit board uneven. Thus, the circuit board may be damaged by overheating in the areas with more current and have a shorter lifespan.

In addition, because the upper conductive layers transmits higher current than the lower conductive layers, the total number of the vias arranged on the circuit board needs to be enough to enable each conductive layer to transmit a even current, which may increase impedance of the circuit board and lead to a lower current transmission efficiency.

Therefore, there is room for improvement within the art.

Many aspects of the present disclosure can be better understood with reference to the following drawings. The elements 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 schematic view of a circuit board, according to an exemplary embodiment of the disclosure.

FIG. 2 is a cross-sectional view of the circuit board, taken along line II-II of FIG. 1 .

FIG. 1 is a schematic view of a circuit board 100 , according to an exemplary embodiment of the disclosure. The circuit board 100 includes a plurality of conductive layers 10 , a plurality of groups of first vias 30 , a plurality of second vias 50 , a plurality of power supply elements 70 , and an electronic element 90 . The power supply elements 70 and the electronic element 90 are mounted on the circuit board 100 . Both the first vias 30 and the second vias 50 extend through all the conductive layers 10 . The power supply elements 70 provide electrical power to the electronic element 90 through the conductive layers 10 , the first vias 30 , and the second vias 50 .

The conductive layers 10 are spacedly positioned, and parallel to each other. The conductive layers 10 may be signal layers or power supply layers. Each conductive layer 10 includes a main body 11 and a conductive portion 13 embedded in the main body 11 . In the exemplary embodiment, the main bodies 11 can be made of insulated material, and the conductive portions 13 can be copper foil layers. Due to the different shapes of the conductive portions 13 , each conductive portion 13 may have different resistances. The surface conductive portion 13 electronically connects to both the power supply elements 70 and the electronic element 90 , and all the conductive portions 13 transmit current from the power supply element 70 to the electronic element 90 .

Referring to FIG. 2 , each first via 30 includes a first through hole 31 and a first conductive inner wall 33 . The first conductive inner wall 33 is plated on an inner surface of each first through hole 31 . Thus, parts of each the conductive layers 10 facing the power supply element 70 can be electrically connected by the first conductive inner walls 33 .

In this exemplary embodiment, each group of the first vias 30 is arranged surrounding each power supply element 70 to form a current flowing region 40 on each conductive layer 10 . A shape of the current flowing region 40 corresponds to a profile of the power supply element 70 . In exemplary embodiment, the current flowing region 40 is rectangular. When the power supply elements 70 provide electrically power to the electronic element 90 , current is output into the surface current flowing region 40 on the surface conductive layer 10 . So that a first portion of the output current flows to the inner conductive layers 10 through the first vias 30 , and a second portion of the output current still flows along the surface conductive layer 10 . Thus, the current from the power supply elements 70 can be distributed into each conductive layer 10 , and transmitted by all the conductive layers 10 .

The number of each group of the first vias 30 surrounded each power supply element 40 can be changed according to a value of the current output from each power supply element 40 and a maximum value of the current flowing through each first via 30 . In the illustrated embodiment, for example, when the value of the current output from each power supply element 70 is about 40 A, and the maximum current flowing through each via 30 is about 2.5 A, the number of each group of first vias 30 is about twenty.

The second vias 50 have the same structure as the first vias 30 . Each second via 50 includes a second through hole 51 and a second conductive inner wall 53 . Thus, parts of each conductive layer 10 between the power supply elements 70 and the electronic element 90 can be electrically connected to each other via the second conductive inner walls 53 . In the exemplary embodiment, the second vias 50 are positioned between the power supply elements 70 and the electronic elements 90 , and arranged along the peripheral edge of the conductive portion 13 so each conductive layer 10 has a lower resistance.

In this exemplary embodiment, the current from the power supply elements 70 is distributed to each conductive layer 10 through the first vias 30 . Then the second vias 50 guide the current on each conductive portion 13 to continuously flow to a top/down conductive portion 13 having a lower resistance, until the current is transmitted to the electronic element 90 . Thus, each conductive portion 13 will have a higher transmission speed and a lower transmission lost.

In an exemplary embodiment, the electronic element 90 is a processor. A plurality of component holes 91 is defined in the circuit board 100 corresponding to the electronic element 90 . The component holes 91 have the same structure as the first vias 30 , and each component hole 91 includes a third through hole 911 and a third conductive inner wall 913 plated on an inner surface of the third through hole 911 . Pins (not shown) of the electronic element 90 can be received in the component holes 91 , and electrically connects to the third conductive inner wall 913 . So that he electronic element 90 can electrically connect to the conductive layers 10 via the component holes 91 . Therefore, both the first portion of the current flowing through the inner conductive layers 10 and the second portion of the current flowing through the surface conductive layer 10 are converged at the component holes 91 on the surface conductive layer 10 , and input into the electronic element 90 through the component holes 91 on the surface conductive layer 10 .

The groups of the first vias 30 arranged surrounding each power supply element 40 have a regular distribution, to distribute current from the supply element 70 to each conductive layer 10 , and the second vias 50 are arranged to adjust current transmitting on each conductive layer 10 during transmission. Thus, the circuit board 100 can have even current distribution. In addition, because each first via 30 is effectively used, the second vias 50 are only arranged along the peripheral edge of the conductive portion 13 , the total number of the first vias 30 and the second vias 50 can be reduced to obtain higher current transmission efficiency and lower transmission lost.

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.