CN110113863B

CN110113863B - PCB board with electrostatic protection function

Info

Publication number: CN110113863B
Application number: CN201910385636.5A
Authority: CN
Inventors: 于静
Original assignee: Wuhan Jingce Electronic Group Co Ltd; Wuhan Jingli Electronic Technology Co Ltd
Current assignee: Wuhan Jingce Electronic Group Co Ltd; Wuhan Jingli Electronic Technology Co Ltd
Priority date: 2019-05-09
Filing date: 2019-05-09
Publication date: 2024-04-19
Anticipated expiration: 2039-05-09
Also published as: CN110113863A

Abstract

The invention discloses a PCB with an electrostatic protection function, and relates to the technical field of electrostatic protection; the PCB comprises a substrate, an external connector, a first ESD device and an internal circuit, wherein the external connector, the first ESD device and the internal circuit are arranged on the substrate; the external connector is connected with the internal circuit through a first ESD device, and a first conductive layer is paved below the external connector; a second conductive layer is laid below the internal circuit; the first conductive layer and the second conductive layer are arranged in a split mode and connected through the first ESD device; according to the invention, the conductive layers paved on the external connector and the internal circuit are subjected to segmentation treatment, so that the external connector and the internal circuit release charges outwards through different ways, thereby effectively avoiding damage to the PCB caused by external discharge and improving the electrostatic protection performance of the PCB.

Description

PCB board with electrostatic protection function

Technical Field

The invention belongs to the technical field of static electricity protection, and particularly relates to a PCB with a static electricity protection function.

Background

PCB (Printed Circuit Board), the Chinese name is printed circuit board, which is the support of electronic components and is the carrier for the electrical connection of electronic components. It is called a "printed" circuit board because it is made using electronic printing. After the electronic equipment adopts the printed board, due to the consistency of the similar printed boards, the error of manual wiring is avoided, the automatic insertion or mounting, automatic soldering and automatic detection of electronic components can be realized, the quality of the electronic equipment is ensured, the labor productivity is improved, the cost is reduced, and the maintenance is convenient.

The technical problems existing in the research and development process of the PCB are eliminated, and once the PCB has faults in the use process, the PCB is mostly related to static electricity; static electricity is ubiquitous and for some tiny electronic components, the entire production line will face breakdown as long as it breaks down. The static electricity has the following adverse effects on electronic components: 1. dust is adsorbed by static electricity, so that the insulation resistance of components is reduced, and the service life of the components is shortened; 2. the static discharge or the current generates heat, which is the potential damage to the components; 3. the electromagnetic field generated by the electrostatic discharge has large amplitude and extremely wide frequency spectrum, and causes interference and even damage to electronic devices; 4. the electrostatic discharge damage causes the damage of the components and the failure of normal operation; it follows that the damage caused by static electricity is not estimated.

At present, signals sent out from an external interface (connector) of a PCB product are connected with an electrostatic discharge (Electro-STATIC DISCHARGE, ESD) protection device, and the ESD protection device is used for carrying out electrostatic protection on the PCB; however, even if the ESD device is adopted, a good electrostatic protection effect cannot be achieved, the above PCB board with the ESD device is tested by using the electrostatic tester, and experimental results show that when 15KV static is applied to the PCB board, the internal circuit of the PCB board is broken down, which indicates that the existing PCB board with the ESD device has poor electrostatic protection effect, and the electrostatic protection performance of the PCB board needs to be further improved, so that the use safety of the PCB board is improved.

Disclosure of Invention

Aiming at least one defect or improvement requirement of the prior art, the invention provides the PCB with the electrostatic protection function, and the external connector and the internal circuit release charges outwards through different ways by dividing the conductive layers paved on the external connector and the internal circuit, so that the damage to the PCB caused by external discharge is effectively avoided, the electrostatic protection performance of the PCB is improved, and the invention aims to solve the problem of poor electrostatic protection effect of the traditional PCB.

In order to achieve the above object, according to one aspect of the present invention, there is provided a PCB board having an electrostatic protection function, comprising a substrate, and an external connector, a first ESD device and an internal circuit provided on the substrate;

the external connector is connected with the internal circuit through a first ESD device, and a first conductive layer is paved below the external connector; a second conductive layer is laid below the internal circuit; the first conductive layer and the second conductive layer are arranged in a split mode and connected through the first ESD device.

Preferably, the above PCB board with electrostatic protection function further includes an RC circuit and a ground hole; the first grounding pin of the RC circuit is electrically connected with the first conductive layer, and the second grounding pin is electrically connected with the grounding hole.

Preferably, the above PCB board with electrostatic protection function further includes a second ESD device; the second ESD device is arranged on the first conductive layer, one end of the second ESD device is connected with the external connector, and the other end of the second ESD device is connected with the first ESD device.

Preferably, the substrate of the PCB board with the electrostatic protection function includes a top layer, a ground layer, a power layer and a bottom layer; an external connector, a first ESD device, a second ESD device, an internal circuit and an RC circuit are arranged above the top layer; and a first conductive layer and a second conductive layer are paved above the grounding layer.

Preferably, in the above PCB board with electrostatic protection function, the power layer and the ground layer are correspondingly laid with a first conductive layer and a second conductive layer at opposite positions.

Preferably, in the above PCB board with electrostatic protection function, the second ESD device is layered at a position opposite to the top layer and the bottom layer.

Preferably, in the above PCB board with electrostatic protection function, a laying width of a junction between the first conductive layer and the RC circuit is greater than 2mm, and a plurality of metal through holes are formed thereon.

Preferably, the wiring width between the RC circuit and the grounding hole of the PCB with the electrostatic protection function is larger than 2mm.

Preferably, the first ESD device of the PCB board with electrostatic protection function is CDDFN-0524P; the second ESD device is P40-G.

Preferably, the first conductive layer and the second conductive layer of the PCB board with the electrostatic protection function are copper foils.

In general, the above technical solutions conceived by the present invention, compared with the prior art, enable the following beneficial effects to be obtained:

(1) According to the PCB with the electrostatic protection function, the conductive layers laid on the external connector and the internal circuit are subjected to segmentation treatment, so that the external connector and the internal circuit release charges outwards through different ways, damage to the PCB caused by external discharge is effectively avoided, and the electrostatic protection performance of the PCB is improved.

(2) According to the PCB with the electrostatic protection function, the first conductive copper foil is independently paved below the second ESD device and the external connector, the first conductive copper foil is directly led to the RC circuit, and the second conductive copper foil is independently paved below the internal circuit; the external connector discharges charges to the ground of the external shell through the second ESD device, the first conductive copper foil and the RC circuit; and the internal circuit is grounded through the first ESD device and the second conductive copper foil, so that damage to the PCB caused by external discharge is effectively avoided.

(3) According to the PCB with the electrostatic protection function, the second ESD devices are arranged at the opposite positions of the top layer and the bottom layer in a layered mode, the occupied area of the components can be reduced on the premise that the wiring sequence and the design requirement are met, and therefore the size of the PCB is reduced, and the trend of miniaturization of the PCB is met.

Drawings

Fig. 1 is a schematic plan view of a PCB board with electrostatic protection function according to an embodiment of the present invention;

FIG. 2 is a schematic view of a partially enlarged structure of a junction between a first conductive layer and a second conductive layer according to an embodiment of the present invention;

Like reference numerals denote like technical features throughout the drawings, in particular: 1-a substrate; 2-an external connector; 3-a first ESD device; 4-a second ESD device; 5-an internal circuit; 6-a first conductive layer; 7-a second conductive layer; 8-ground dividing line; 9-grounding feet; a 10-RC circuit; 11-a grounding screw hole; 12-metal vias.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

Example 1

The PCB board with the electrostatic protection function provided by the embodiment comprises a substrate 1, an external connector 2, a first ESD device 3, a second ESD device 4 and an internal circuit 5, wherein the external connector 2, the first ESD device 3, the second ESD device 4 and the internal circuit 5 are arranged on the substrate 1; the external connector 2 is connected with the internal circuit 5 through the second ESD device 4 and the first ESD device 3 in sequence;

The first ESD device 3 preferably employs CDDFN a 10-0524p,0524p primarily for providing ESD for high levels, EFT and surge protection speed data ports are satisfactory; the second ESD device 4 preferably employs P40-G, the P40 device being a high-speed bi-directional protection element intended to prevent a fault short, ac power cross induction and lightning surge caused thereby. In the embodiment, the two ESD devices are matched for use, so that the PCB is effectively protected against static electricity. The PCB with the electrostatic protection function provided by the embodiment is tested by adopting the electrostatic tester, 12KV static electricity is applied to the PCB, and an internal circuit of the PCB is not broken down, so that the PCB provided by the embodiment has a good electrostatic protection effect.

Example two

Fig. 1 is a schematic plan view of a PCB board with electrostatic protection function according to a second embodiment of the present invention; as shown in fig. 1, the PCB includes a substrate 1, an external connector 2 provided on the substrate 1, a first ESD device 3, and an internal circuit 5; the external connector 2 is connected to the internal circuit 5 via the first ESD device 3,

A first conductive layer 6 is laid under the external connector 2; a second conductive layer 7 is laid below the internal circuit 5; the first conductive layer 6 and the second conductive layer 7 are arranged in a split way, so that a ground split line 8 is generated; the first ESD device 3 is provided on the ground dividing line 8, and the first conductive layer 6 and the second conductive layer 7 are connected to each other through the first ESD device 3.

In order to further improve the electrostatic protection effect, the PCB board with the electrostatic protection function further includes a second ESD device 4 disposed on the first conductive layer 6 near the external connector 2, one end of the second ESD device is connected to the external connector 2, and the other end is connected to the first ESD device 3.

Fig. 2 is a schematic view of a partially enlarged structure of a junction between a first conductive layer and a second conductive layer according to the present embodiment; as shown in fig. 2, two ground legs 9 of the first ESD device 3 are located on the first conductive layer 6 and the second conductive layer 7, respectively; the first ESD device 3 may adopt an ESD protection device with a grounding pin to realize connection and electrostatic protection functions, and in this embodiment, the first conductive layer and the 6 second conductive layer 7 are common copper foils; the first ESD device 3 preferably employs CDDFN a 10-0524P; the second ESD device 4 preferably employs P40-G; in the embodiment, the two ESD devices are matched for use on the premise of carrying out segmentation treatment on the conductive layer, so that the PCB is more effectively protected.

The current of the power supply is conducted out through the ground, if the ground is a whole, the internal circuit and the external connector release charges outwards through the same ground, so that when the external air discharges or the human body discharges to a certain height, the external air enters the PCB through the ground, and the internal circuit of the PCB is damaged; according to the embodiment, the conductive layers paved on the external connector and the internal circuit are subjected to segmentation treatment, so that the external connector and the internal circuit release charges outwards through different ways, the damage to the PCB caused by external discharge is effectively avoided, and the electrostatic protection performance of the PCB is improved.

When the PCB is designed and laid out, the external connectors are placed towards the same direction as much as possible so as to be subjected to subsequent segmentation treatment through the conductive layer; if the external connectors are distributed in different areas, then copper foil needs to be laid separately under the external connectors in each area; in addition, the closer the first ESD device 3 and the second ESD device 4 are to the external connector, the more orderly the first ESD devices CDDFN-0524P are placed as possible, and the distance between the first ESD device and the surrounding components is up to more than 2 mm, so that the later stage of the segmentation processing can be performed.

As one preferable example of this embodiment, the PCB with electrostatic protection function further includes an RC circuit 10 and a grounding screw hole 11; the first grounding pin of the RC circuit 10 is electrically connected with the first conductive layer 6, and the second grounding pin is electrically connected with the grounding screw hole 11; the laying width of the joint of the first conductive layer 5 and the RC circuit 10 is more than 2mm, so that the current can be sufficiently large, and a plurality of metal through holes 12 are formed on the joint; the grounding screw hole 11 is a copper-clad hole, and the wiring width between the RC circuit 10 and the grounding screw hole 11 is greater than 2mm, so that the passing current is large enough, and the current discharging capability is improved.

After the conducting layer is divided, the external connector 2 discharges the charges to the external shell ground through the second ESD device 4, the first conducting layer 6 and the RC circuit 10; and the internal circuit 5 is grounded through the second conductive layer 7 and the first ESD device 3, so that damage to the PCB caused by external discharge is effectively avoided.

As one preferable example of the present embodiment, the substrate 1 of the PCB board with electrostatic protection function adopts four layers, including a top layer, a ground layer, a power layer and a bottom layer; the external connector 2, the first ESD device 3, the second ESD device 4, the internal circuit 5 and the RC circuit 10 are all disposed above the top layer; the first conductive layer 6 and the second conductive layer 7 which are arranged in a split manner are laid above the ground layer. Preferably, the first conductive layer 6 and the second conductive layer 7 are correspondingly laid at the relative positions of the power supply layer and the ground layer, and the first conductive layer 6 and the second conductive layer 7 which are arranged on the power supply layer in a splitting mode are mainly used for splitting a power supply and are matched and fused with the conductive layers laid on the ground layer. In addition, the invention is also applicable to other layers of PCB boards, such as two-layer boards, six-layer boards, etc., and is not limited to the four-layer boards provided in the present embodiment.

As one preferable example of the present embodiment, in the PCB board with the electrostatic protection function, the second ESD device 4 is layered at the opposite position of the top layer and the bottom layer, that is, the second ESD device 4 is layered on the front and back sides of the substrate; the structure can reduce the occupied area of components on the premise of meeting the wiring sequence and design requirements, thereby reducing the volume of the PCB and meeting the miniaturization trend of the PCB.

The electrostatic tester is adopted to test the PCB with the electrostatic protection function provided by the embodiment, 15KV static electricity is applied to the PCB, and the internal circuit of the PCB is not broken down, so that the electrostatic protection effect of the PCB provided by the embodiment is good, and the PCB has better use safety compared with the existing PCB only adopting an ESD device.

Compared with the existing PCB product, the PCB with the electrostatic protection function provided by the invention has the advantages that the first conductive copper foil is independently paved below the external connector, the first conductive copper foil is directly led to the RC circuit, and the second conductive copper foil is independently paved below the internal circuit; the external connector discharges charges to the ground of the external shell through the first conductive copper foil and the RC circuit; and the internal circuit is grounded through the second conductive copper foil and the first ESD device, so that damage to the PCB caused by external discharge is effectively avoided.

It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. The PCB board with the electrostatic protection function is characterized by comprising a substrate, an external connector, a first ESD device and an internal circuit, wherein the external connector, the first ESD device and the internal circuit are arranged on the substrate;

The external connector is connected with the internal circuit through a first ESD device, and a first conductive layer is paved below the external connector; a second conductive layer is laid below the internal circuit; the first conductive layer and the second conductive layer are arranged in a dividing way to generate a ground dividing line; the first ESD device is arranged on the ground dividing line, so that the first conductive layer and the second conductive layer are connected through the first ESD device.

2. The PCB with electrostatic protection of claim 1, further comprising an RC circuit and a ground hole; the first grounding pin of the RC circuit is electrically connected with the first conductive layer, and the second grounding pin is electrically connected with the grounding hole.

3. The PCB with electrostatic protection function of claim 2, further comprising a second ESD device; the second ESD device is arranged on the first conductive layer, one end of the second ESD device is connected with the external connector, and the other end of the second ESD device is connected with the first ESD device.

4. The PCB with electrostatic protection according to claim 3, wherein the substrate includes a top layer, a ground layer, a power layer, and a bottom layer; an external connector, a first ESD device, a second ESD device, an internal circuit and an RC circuit are arranged above the top layer; and a first conductive layer and a second conductive layer are paved above the grounding layer.

5. The PCB with electrostatic protection of claim 4, wherein the second ESD device layer is disposed in a relative position of the top layer and the bottom layer.

6. The PCB with electrostatic protection according to claim 1 or 5, wherein a laying width of a junction between the first conductive layer and the RC circuit is greater than 2mm, and a plurality of metal through holes are formed thereon.

7. The PCB with electrostatic protection of claim 6, wherein a routing width between the RC circuit and the ground hole is greater than 2mm.

8. The PCB with electrostatic protection function of claim 3, wherein the first ESD device is CDDFN-0524P; the second ESD device is P40-G.

9. The PCB with electrostatic protection of claim 8, wherein the first conductive layer and the second conductive layer are copper foil.