CN106255307A - Circuit board - Google Patents

Abstract

A kind of circuit board, including a signals layer and a ground plane, a Difference signal pair has been laid on described signals layer, the corresponding described Difference signal pair of described ground plane is provided with a defect grounding structure, and described defect grounding structure position on described ground plane is corresponding with described Difference signal pair position on described signals layer.

Description

circuit board

technical field

The invention relates to a circuit board on which differential signal pairs are arranged.

Background technique

Differential signal transmission is a signal transmission technology that transmits signals on two lines. The amplitudes of the two signals are equal and the phases are opposite. When a differential signal pair is used to transmit signals on a circuit board, a common mode will be generated on the transmission line. These common-mode noises will affect the timing of signal transmission, reduce the integrity and strength of differential signals, and common-mode noise will also cause electromagnetic interference.

Contents of the invention

In view of the above, it is necessary to provide a circuit board that can effectively suppress common mode noise.

A circuit board, comprising a signal layer and a ground layer, a differential signal pair is arranged on the signal layer, and a defective ground structure is provided on the ground layer corresponding to the differential signal pair, and the defective ground structure is placed on the The location on the ground layer corresponds to the location of the differential signal pair on the signal layer.

Compared with the prior art, the above-mentioned circuit board reduces electromagnetic interference caused by common-mode noise on the differential signal pair by providing a defective ground structure on the ground layer.

Description of drawings

FIG. 1 is a schematic diagram of a preferred embodiment of the circuit board of the present invention.

FIG. 2 is a perspective view of the circuit board in FIG. 1 .

FIG. 3 is a schematic diagram of a first embodiment of a defect grounding structure in the circuit board of FIG. 2 .

FIG. 4 is a schematic diagram of a defect ground structure and differential signal pairs in the circuit board of FIG. 3 .

FIG. 5 is a schematic diagram of a second embodiment of a defect grounding structure in the circuit board of FIG. 2 .

FIG. 6 is a schematic diagram of a third embodiment of a defect grounding structure in the circuit board of FIG. 2 .

FIG. 7 is a schematic diagram of a fourth embodiment of a defect grounding structure in the circuit board of FIG. 2 .

FIG. 8 is a schematic diagram of a fifth embodiment of a defect grounding structure in the circuit board of FIG. 2 .

Description of main component symbols

circuit board 10 Insulation 13 Solder mask 15 signal layer twenty one ground plane twenty three differential signal pair 30 first signal line 31 second signal line 32 defective ground structure 50, 60, 70, 80, 90 Knockout 51, 61, 71, 81, 91 first slot 511, 611, 911 second slot 515, 615, 915 first wavy groove 5111 Second wave groove 5112 connection slot 5113, 6113, 7113, 8113, 9113 first straight slot 6111, 7111 Second straight groove 6112, 7112 groove 711, 811 first inclined slot 8111, 9111 second inclined slot 8112, 9112

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

detailed description

Please refer to FIG. 1 , which is a schematic diagram of a circuit board 10 of the present invention. The circuit board 10 includes a plurality of dielectric layers. These dielectric layers include an insulating layer 13 and a solder resist layer 15. The insulating layer 13 is usually made of poly Made of insulating materials such as propylene, the circuit board 10 is respectively provided with a signal layer 21 and a ground layer 23 on both sides of the insulating layer 13, and a differential signal pair 30 is arranged on the signal layer 21, and the differential signal pair 30 includes mutually parallel a first signal line 31 and a second signal line 32 .

Please refer to FIG. 2 , the ground layer 23 can be a ground conductive plate, such as a copper foil, and a defective ground structure 50 is provided on the ground layer 23 to reduce the electromagnetic interference generated by the differential signal pair 30 .

Please refer to FIG. 3 , the defective grounding structure 50 includes two hollowed out areas 51, which are symmetrical to a central line between the two hollowed out areas 51, and each hollowed out area 51 includes a roughly "C" shaped first Groove 511 and two second grooves 515, the two second grooves 515 communicate with the first groove 511 respectively, the two first grooves 511 of the two hollowed out areas 51 are symmetrically arranged opposite each other, and the two "C" shaped first grooves The openings of the two "C" characters of 511 are opposite, and each "C"-shaped first groove 511 includes a first wave-shaped groove 5111, a second wave-shaped groove 5112 and a connecting groove 5113, and the connecting groove 5113 communicates with the Between the first wave-shaped groove 5111 and the second wave-shaped groove 5112, the first wave-shaped groove 5111 and the second wave-shaped groove 5112 are symmetrically arranged relative to a center line between the two, and the two second grooves 515 A second groove 515 of one is communicated with the joint of the first wave-shaped groove 5111 and the connecting groove 5113, and another second groove 515 is communicated with the joint of the second wave-shaped groove 5112 and the connecting groove 5113; The extension direction of the second groove 515 is opposite to the opening direction of the "C"-shaped first groove 511, and the two second grooves 515 are symmetrical to a center line between the first signal line 31 and the second signal line 32, The entire defective ground structure 50 is also symmetrical with respect to a central line between the first signal line 31 and the second signal line 32 .

Please refer to FIG. 4, the differential signal pair 30 is roughly parallel to the first wave-shaped groove 5111 and the second wave-shaped groove 5112, and the orthographic projection of the differential signal pair 30 on the ground layer 23 covers the first wave-shaped groove 5111 and the second wave-shaped groove 5111. Adjacent areas of the two wavy grooves 5112 .

Please refer to FIG. 5 , which is a schematic diagram of a second embodiment of the defective grounding structure. The defective grounding structure 60 in the second embodiment also includes two hollowed out areas 61, and each hollowed out area 61 includes a roughly " The first groove 611 and two second grooves 615 of C" shape, the two second grooves 615 communicate with the first groove 611 respectively, the two first grooves 611 of the two hollowed out areas 61 are symmetrically arranged, and the two "C The openings of the two "C" characters of the "shaped first groove 611 are opposite, and each "C" shaped first groove 611 includes a first straight groove 6111, a second straight groove 6112 and a connecting groove 6113. The groove 6113 communicates between the first straight groove 6111 and the second straight groove 6112, the first straight groove 6111 and the second straight groove 6112 are parallel to each other, and the connection groove 6113 is approximately Vertically, the first signal line 31 and the second signal line 32 of the differential signal pair 30 are respectively aligned with the first straight groove 6111 and the second straight groove 6112, and a second groove 615 in the two second grooves 615 is connected to the first straight groove 6115. At the junction of the straight groove 6111 and the connecting groove 6113, another second groove 615 communicates with the junction of the second straight groove 6112 and the connecting groove 6113; the extension direction of the two second grooves 615 is consistent with the "C" shape The opening directions of the first slots 611 are opposite.

Please refer to FIG. 6, which is a schematic diagram of a third embodiment of the defective grounding structure. The defective grounding structure 70 in the third embodiment also includes two hollowed out areas 71, and each hollowed out area 71 includes a roughly " C"-shaped groove 711, the groove 711 includes a first straight groove 7111, a second straight groove 7112 and a connecting groove 7113, the connecting groove 7113 communicates between the first straight groove 7111 and the second straight groove 7112 , the first straight groove 7111 and the second straight groove 7112 are parallel to each other, the connection groove 7113 is approximately perpendicular to the first straight groove 7111 and the second straight groove 7112, the first signal line 31 and the second signal line 32 of the differential signal pair 30 Aligned with the first straight slot 7111 and the second straight slot 7112 respectively, the connection slot 7113 is approximately perpendicular to the differential signal pair 30 .

Please refer to FIG. 7 , which is a schematic diagram of a fourth embodiment of the defective grounding structure. The defective grounding structure 80 in the fourth embodiment also includes two hollowed out areas 81, and each hollowed out area 81 includes a roughly " C"-shaped groove 811, the groove 811 includes a first inclined groove 8111, a second inclined groove 8112 and a connecting groove 813, the connecting groove 813 is connected between the first inclined groove 8111 and the second inclined groove 8112, the The differential signal pair 30 is inclined relative to the first inclined slot 8111 and the second inclined slot 8112 , and the connection slot 8113 is substantially perpendicular to the differential signal pair 30 .

Please refer to FIG. 8 , which is a schematic diagram of a fifth embodiment of the defective grounding structure. The defective grounding structure 90 in the fifth embodiment also includes two hollowed out regions 91, and each hollowed out region 91 includes a roughly A "C" shaped first groove 911 and two second grooves 915, the two second grooves 915 communicate with the first groove 911 respectively, each "C" shaped first groove 911 includes a first inclined groove 9111, A second inclined slot 9112 and a connecting slot 9113, the connecting slot 9113 communicates between the first inclined slot 9111 and the second inclined slot 9112, the differential signal pair 30 is opposite to the first inclined slot 9111 and the second inclined slot 9112 is inclined, and the connection groove 9113 is approximately perpendicular to the differential signal pair 30. One of the two second grooves 915 is connected to the connection between the first inclined groove 9111 and the connection groove 9113, and the other second groove 911 The second groove 915 communicates with the junction of the second inclined groove 9112 and the connecting groove 9113; the extending direction of the two second grooves 915 is opposite to the opening direction of the "C" shaped first groove 911.

In the above embodiment, the defective ground structure is formed on the ground layer 23 by etching, thereby reducing electromagnetic interference caused by common-mode noise on the differential signal pair, especially for low-frequency signals below 2.5 GHz, The effect of reducing electromagnetic interference is more obvious.

Claims (9)

1. A circuit board, comprising a signal layer and a ground layer, a differential signal pair is arranged on the signal layer, characterized in that: the ground layer is provided with a defect grounding structure corresponding to the differential signal pair, the The position of the defective ground structure on the ground layer corresponds to the position of the differential signal pair on the signal layer. 2 . The circuit board according to claim 1 , wherein the defective grounding structure comprises two hollowed out areas, and the two hollowed out areas are symmetrical with respect to a central line therebetween. 3 . 3. The circuit board according to claim 2, wherein a part of the ground layer is etched to form the defective ground structure. 4. The circuit board according to claim 2, wherein the hollowed out area comprises a first groove, and the first groove comprises a first wave groove, a second wave groove and a connecting groove, so that The first wave-shaped groove is parallel to the second wave-shaped groove, the connecting groove communicates between the first wave-shaped groove and the second wave-shaped groove, and the first wave-shaped groove and the second wave-shaped groove The wavy grooves are arranged symmetrically relative to a central line between the two. 5. The circuit board according to claim 4, wherein the hollowed out area further comprises two second grooves, one of the two second grooves is connected to the first wave-shaped groove At the junction with the connecting groove, another second groove communicates with the junction of the second wave-shaped groove and the connecting groove. 6. The circuit board according to claim 5, wherein the orthographic projection of the differential signal pair on the ground layer covers the adjacent first wave-shaped groove and the second wave-shaped groove Area. 7. The circuit board according to claim 2, wherein each hollowed-out area comprises a groove, and the groove comprises a first straight groove, a second straight groove and a connecting groove, and the connecting groove communicates with Between the first straight groove and the second straight groove, the first straight groove and the second straight groove are parallel to each other, the connecting groove is substantially perpendicular to the first straight groove and the second straight groove, The differential signal pair is aligned with the first straight slot and the second straight slot, and the connection slot is perpendicular to the differential signal pair. 8. The circuit board according to claim 2, wherein each hollowed-out area includes a groove, and the groove includes a first inclined groove, a second inclined groove and a connecting groove, and the connecting groove connects Between the first inclined slot and the second inclined slot, the differential signal pair is arranged obliquely relative to the first inclined slot and the second inclined slot, and the connecting slot is perpendicular to the differential signal pair. 9. The circuit board according to claim 2, wherein each hollowed-out area comprises a first groove and two second grooves, and the first groove comprises a first inclined groove, a second inclined groove and a connecting slot, the connecting slot communicates between the first inclined slot and the second inclined slot, the differential signal pair is arranged obliquely relative to the first inclined slot and the second inclined slot, and the connecting slot is perpendicular to For the differential signal pair, one second slot of the two second slots is connected to the connection between the first inclined slot and the connection slot, and the other second slot is connected to the second inclined slot and the connecting slot. The joint of the above-mentioned connecting groove.