CN210183629U

CN210183629U - Static electricity eliminating device

Info

Publication number: CN210183629U
Application number: CN201920773933.2U
Authority: CN
Inventors: Hui Duan; 段辉; Guoyong Ye; 叶国勇; Ruigang Hu; 胡瑞刚
Original assignee: Huizhou Weite Technology Co Ltd
Current assignee: Huizhou Weite Technology Co Ltd
Priority date: 2019-05-27
Filing date: 2019-05-27
Publication date: 2020-03-24
Anticipated expiration: 2029-05-27

Abstract

The utility model discloses a static elimination device, which comprises a shell, a PCB and an anti-static component, wherein the shell is internally provided with an installation cavity, and the PCB and the anti-static component are respectively accommodated in the installation cavity; the anti-static component comprises a protective circuit board, a grounding wire, a patch diode and a plurality of magnetic beads, wherein the protective circuit board is arranged in the installation cavity, the first end of the grounding wire is connected with the protective circuit board, the second end of the grounding wire is connected with the shell, the patch diode is arranged on the protective circuit board and electrically connected with the grounding end of the shell, the first end of each magnetic bead after being connected in series is connected with the PCB, and the second end of each magnetic bead after being connected in series is connected with the grounding end of the shell. Therefore, the static electricity on the product can be inhibited and eliminated, so that the product can be prevented from being broken down and damaged by the static electricity, the first pass rate and the finished product rate of the product can be improved, and the waste of economy and materials caused by static electricity interference is avoided.

Description

Static electricity eliminating device

Technical Field

The utility model relates to an electrostatic elimination field of electronic product especially relates to an electrostatic elimination device.

Background

Static electricity is a static or non-flowing charge (a flowing charge forms a current). Static electricity is formed when charges are accumulated on an object or a surface, and the charges are classified into two kinds of positive charges and negative charges, that is, the static electricity phenomenon is also classified into two kinds, i.e., positive static electricity and negative static electricity. Positive static electricity is formed when positive charges are accumulated on an object, and negative static electricity is formed when negative charges are accumulated on an object. Although it is not seen very often by us, its shadow is everywhere. Not only does this seriously affect our lives and work, but also the harm it brings is very huge. In the following, we mainly describe the influence of static electricity on electronic products and the design scheme of static electricity discharge.

Electrostatic hazard to electronic products: dust is adsorbed to cause pollution of an integrated circuit and a semiconductor element, and the yield is greatly reduced; breakdown of integrated circuits and precision electronic components, or aging of components, lowering production yield; causing malfunction or malfunction of the electronic device, directly affecting the use of the consumer, and the like. Then, in order to eliminate the damage caused by static electricity, engineers may perform some treatment when designing the circuit, such as: the metal shell is connected with the ground; a pressure sensitive resistor; adding a TVS device; adding inductance, capacitance, etc. The treatments usually have certain effect on eliminating static electricity, but are far from enough for products with stricter requirements and higher antistatic grade. This results in unnecessary waste and failure to maximize the efficiency of the components used. It is particularly important to consider the design of the housing structure and the ground connection, as well as the selection of the anti-static components and the matching of the components.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming the weak point among the prior art, provide an electrostatic elimination device, can restrain and eliminate the static on the product, so both can make the product avoid the trouble and the damage that static brought, can improve the direct rate and the yield of product again to the waste on economy and the material brought by electrostatic interference has been avoided.

The purpose of the utility model is realized through the following technical scheme:

an electrostatic eliminating apparatus comprising: the anti-static PCB comprises a shell, a PCB and an anti-static component, wherein a mounting cavity is formed in the shell, and the PCB and the anti-static component are respectively accommodated in the mounting cavity;

the shell comprises a shell body and a fixing screw, a through hole is formed in the shell body, and the fixing screw penetrates through the through hole;

the anti-static component comprises a protection circuit board, a grounding wire, a patch diode and a plurality of magnetic beads, wherein the protection circuit board is arranged in the installation cavity, the first end of the grounding wire is connected with the protection circuit board, the second end of the grounding wire is connected with the shell, the patch diode is arranged on the protection circuit board, one end of the patch diode is used for electrically connecting external input voltage, the other end of the patch diode is electrically connected with the grounding end of the shell, the first end of the magnetic bead after series connection is connected with the PCB, and the second end of the magnetic bead after series connection is connected with the grounding end of the shell.

In one embodiment, the PCB board includes a circuit substrate disposed in the mounting cavity and an anti-static circuit disposed on the circuit substrate.

In one embodiment, the anti-static circuit includes a low-pass filtering unit, a surge absorbing unit and a load, a first end of the low-pass filtering unit is used as an output end of the anti-static circuit, a second end of the low-pass filtering unit is electrically connected with an input end of the load, an input end of the surge absorbing unit is electrically connected with the first end of the low-pass filtering unit, and an output end of the surge absorbing unit is grounded.

In one embodiment, the low-pass filtering unit includes a resistor R1, an inductor L1, and a capacitor C1, a first end of the resistor R1 is used as an output end of the anti-static circuit, a second end of the resistor R1 is electrically connected to one end of the inductor L1 and one end of the capacitor C1, respectively, the other end of the inductor L1 is electrically connected to the load, and the other end of the capacitor C1 is grounded.

In one embodiment, the surge absorption unit is an ESD discharge diode, one end of the ESD discharge diode is electrically connected to the first end of the low-pass filter unit, and the other end of the ESD discharge diode is grounded.

In one embodiment, the anti-static circuit further comprises a static suppressor, one end of the static suppressor is used for electrically connecting an I/O port in the anti-static circuit, and the other end of the static suppressor is grounded.

In one embodiment, the PCB further includes a connection terminal and a plurality of ESD absorbers, the connection terminal is provided with a plurality of connection pins, each of the connection pins is electrically connected to the first end of each of the ESD absorbers in a one-to-one correspondence manner, and the second end of each of the ESD absorbers is grounded.

In one embodiment, two magnetic beads are provided, and the two magnetic beads are connected in series.

In one embodiment, the patch diode is an ESD protection diode.

In one embodiment, the input voltage is an input voltage of + 5V.

The utility model discloses compare in prior art's advantage and beneficial effect as follows:

the utility model relates to an electrostatic elimination device, through setting up protective circuit board and earth connection, can plug up static like this and discharge to the sensitive device on the PCB board, through setting up paster diode and a plurality of magnetic bead, for coupling to the static of +5V input voltage provides a low loop of impedance, has reduced the loop area of static, avoids static to flow through main chip to the suppression decay ESD electric current that the magnetic bead can be fine. Therefore, the static electricity on the product can be inhibited and eliminated, so that the product can be prevented from being broken down and damaged by the static electricity, the first pass rate and the finished product rate of the product can be improved, and the waste of economy and materials caused by static electricity interference is avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural view of an electrostatic elimination device according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of an electrostatic eliminating apparatus according to another embodiment of the present invention;

fig. 3 is a schematic structural view of a static elimination apparatus according to another embodiment of the present invention;

FIG. 4 is a circuit diagram of an anti-static circuit of the static electricity eliminating apparatus shown in FIG. 1;

FIG. 5 is a circuit diagram of a static eliminator of the static eliminating device shown in FIG. 1;

fig. 6 is a circuit diagram of a connection terminal and a plurality of ESD absorbers of the static elimination apparatus shown in fig. 1.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. The preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1 and 2, an electrostatic discharge apparatus includes: the anti-static PCB comprises a shell 100, a PCB 200 and an anti-static component 300, wherein a mounting cavity 110 is formed in the shell, and the PCB and the anti-static component are respectively accommodated in the mounting cavity. It should be noted that the housing 100 is used for protecting the accommodated product and plays a role in protection; the PCB 200 is used to implement functions of a product; the static electricity prevention assembly 300 is used to eliminate and suppress static electricity.

The basic idea of the rectification of electrostatic discharge (ESD) can be summarized as three-character blocking, preventing and dredging. "blocking" as the name implies, is to block electrostatic discharge (ESD) from the outside of the product to the PCB of the product, for example: the ground of the metal shell is completely separated from the ground of the PCB, but is limited by the board sometimes, and the ground of the metal shell is not far separated from the ground of the PCB, and the ESD coupling capability is strong; in this case, if the ground of the metal case is directly separated from the ground of the PCB, secondary discharge is easily caused. So that the magnetic beads with large resistance can be used for serial isolation. In summary, we must pay attention to the distance between the housing and the PCB when designing the housing and structure, and if the housing is a metal housing, grounding process is performed (if the conditions allow).

In one embodiment, referring to fig. 1, the housing 100 includes a casing 120 and a fixing screw 130, the casing is provided with a through hole, and the fixing screw penetrates through the through hole. It should be noted that, the fixing screw 130 is cut off, or replaced by a small screw, or replaced by a plastic screw, so that the screw can be prevented from extending into the housing to form an antenna, so that static electricity is introduced into the PCB.

Referring to fig. 2, 3 and 4, the anti-static assembly 300 includes a protection circuit board 310, a ground line 320, a patch diode 330 and a plurality of magnetic beads 340, the protection circuit board is disposed in the installation cavity, a first end of the ground line is connected to the protection circuit board, a second end of the ground line is connected to the housing, the patch diode is disposed on the protection circuit board, one end of the patch diode is used to electrically connect to an external input voltage, another end of the patch diode is electrically connected to a ground terminal of the housing, a first end of each of the magnetic beads connected in series is connected to the PCB, and a second end of each of the magnetic beads connected in series is connected to the ground terminal of the housing. It should be noted that the protection circuit board 310 is used to prevent static electricity from being introduced into the PCB; the grounding wire 320 is used for introducing static electricity on the protection circuit board into the shell, thereby playing a role of eliminating the static electricity; the surface mount diode 330 is an ESD protection diode and is used for connecting +5V input voltage, so that the function of static electricity prevention is achieved; the magnetic beads 340 are used for being connected with a grounding end of the PCB, and can play a role in blocking static electricity. In this embodiment, the magnetic beads are provided in two, and the two magnetic beads are connected in series. The input voltage is + 5V.

It should be further noted that the anti-static assembly 300 further includes a first fixing plate 350 and a second fixing plate 360, the first fixing plate 350 and the second fixing plate 360 are respectively disposed on the housing, and a first end of the protection circuit board 310 is disposed on the first fixing plate 350, and a second end of the protection circuit board 310 is disposed on the second fixing plate 360. Therefore, the protective circuit board can be installed and fixed, and the stability of stabilizing the product structure and improving the static elimination is achieved.

So, through setting up protection circuit board and earth connection, can block up static like this and discharge to the sensitive device on the PCB board, through setting up paster diode and a plurality of magnetic bead, for coupling to the static circuit that provides a low impedance on the +5V input voltage, reduced the return circuit area of static, avoid static to flow through main chip to the magnetic bead can be fine restrain and attenuate the ESD electric current. Therefore, the static electricity on the product can be inhibited and eliminated, so that the product can be prevented from being broken down and damaged by the static electricity, the first pass rate and the finished product rate of the product can be improved, and the waste of economy and materials caused by static electricity interference is avoided.

Further, the ground of the port is connected with the metal shell so as to enlarge the ESD discharge space. ESD enters the inner part from the gap to cause discharge to sensitive devices on the PCB; an auxiliary grounding protection circuit board is added in the shell, so that static electricity can be blocked to discharge to sensitive devices on the PCB.

Further, "a" in fig. 3 is an ESD protection diode, and "B" is a magnetic bead. The anti-static method is characterized in that a USB metal shell ground is connected with +5V input voltage through an ESD protection diode to play a role in prevention, and then the USB metal shell ground is connected to a PCB ground in series through two magnetic beads to play a role in blocking. Therefore, the ESD device can provide a low-impedance loop for the static coupled to +5V, the loop area of the static is reduced, the static is prevented from flowing through the main chip, and the ferrite magnetic bead can well inhibit and attenuate the ESD current.

It should be noted that the "preventing" is to use ESD protection diode, TVS tube, inductor, capacitor, etc. to form low pass ESD filter and surge ESD absorber to dredge ESD energy for protection, which first we need to understand the approach of ESD interference, if ESD comes from the port, the electrostatic tube is added to the sensitive signal near the port (e.g. D +, D-) of USB port; if the chip is interfered, the electrostatic tube is added on the pin close to the chip, so that ESD is prevented from being coupled into the chip from the back end to cause the failure of the electrostatic tube. It is also worth mentioning that the electrostatic tube provides a discharge path, which cannot absorb and dissipate ESD, so we need to ensure that there is no other sensitive signal line on the discharge path.

It should be noted that the PCB includes a circuit board and an anti-static circuit, the circuit board is disposed in the installation cavity, and the anti-static circuit is disposed on the circuit board.

Referring to fig. 4, the anti-static circuit includes a low-pass filtering unit, a surge absorbing unit and a load, a first end of the low-pass filtering unit is used as an output end of the anti-static circuit, a second end of the low-pass filtering unit is electrically connected to an input end of the load, an input end of the surge absorbing unit is electrically connected to the first end of the low-pass filtering unit, and an output end of the surge absorbing unit is grounded.

Specifically, the low-pass filtering unit includes a resistor R1, an inductor L1, and a capacitor C1, a first end of the resistor R1 is used as an output end of the anti-static circuit, a second end of the resistor R1 is electrically connected to one end of the inductor L1 and one end of the capacitor C1, the other end of the inductor L1 is electrically connected to the load, and the other end of the capacitor C1 is grounded. In this way, by providing the resistor R1, the inductor L1, and the capacitor C1, static electricity can be dissipated, and static electricity can be eliminated.

Specifically, the surge absorption unit is an ESD discharge diode, one end of the ESD discharge diode is electrically connected to the first end of the low-pass filter unit, and the other end of the ESD discharge diode is grounded. Therefore, by arranging the ESD discharge diode, the static electricity of the surge can be absorbed, and the interference of the static electricity is effectively avoided. Thus, ESD energy is conducted in a manner of low-pass ESD filtering and surge ESD absorber

It should be further noted that, referring to fig. 5, the static electricity prevention circuit further includes a static electricity suppressor, one end of the static electricity suppressor is used for electrically connecting to an I/O port in the static electricity prevention circuit, and the other end of the static electricity suppressor is grounded. In this manner, by providing the static electricity suppressor, the I/O port can be made to suppress static electricity by the ESD suppressor.

Referring to fig. 6, the PCB further includes a connection terminal and a plurality of ESD absorbers, the connection terminal is provided with a plurality of connection pins, each of the connection pins is electrically connected to a first end of each of the ESD absorbers in a one-to-one correspondence manner, and a second end of each of the ESD absorbers is grounded. Therefore, the ESD protection diode is added on the connecting terminal or the USB pin for protection, and the interference to the chip and other circuits caused by the introduction of static electricity into the circuit is avoided.

In addition, the final purpose of the 'sparse' is to change the current loop path of the ESD and reduce the loop area. This generally requires the ground on the PCB to be completed, with more vias, and the uniformity of ground impedance.

This is mainly reflected in the Layout of the PCB, and the reasonable Layout of Layout and ground has a close relationship with ESD, which is mainly reflected in the following points:

1. there is a good ground plane. The good ground plane is equipotential, common mode resistance coupling cannot be generated, and circulating current cannot be formed through the ground line to generate an antenna effect; a good ground plane enables the electrostatic discharge to disappear by entering the ground line in the shortest path. The best method for establishing a good ground plane is to use a multilayer board, one layer being used exclusively as a ground plane; if only two-sided boards are available, one should try to run from the front side, which is used as a ground plane.

2. A sufficient distance is maintained. Enough distance is kept for two wires or two groups of wires which can generate ESD coupling or radiation, such as the input and the output of a filter, the input and the output of an optical coupler, an alternating current power wire and a weak signal wire.

3. The long lines require low pass filters. The wiring is as short as possible, and an ESD electrostatic tube, a TVS tube, an RC or LC low-pass filter should be inserted into a reasonable position of a long wire which must be wired.

4. Instead of ground lines, thin lines can be used instead of thick lines. Because each trace on the PCB is not only a carrier of a useful signal, but also a main line for receiving radiation interference, the longer and thicker the trace, the stronger the antenna effect.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An electrostatic eliminating apparatus, comprising: the anti-static PCB comprises a shell, a PCB and an anti-static component, wherein a mounting cavity is formed in the shell, and the PCB and the anti-static component are respectively accommodated in the mounting cavity;

2. The static elimination device of claim 1, wherein the PCB board comprises a circuit substrate and an anti-static circuit, the circuit substrate is disposed in the installation cavity, and the anti-static circuit is disposed on the circuit substrate.

3. The static elimination device according to claim 2, wherein the static electricity prevention circuit comprises a low pass filter unit, a surge absorption unit and a load, a first end of the low pass filter unit is used as an output end of the static electricity prevention circuit, a second end of the low pass filter unit is electrically connected with an input end of the load, an input end of the surge absorption unit is electrically connected with the first end of the low pass filter unit, and an output end of the surge absorption unit is grounded.

4. The static elimination apparatus according to claim 3, wherein the low pass filter unit comprises a resistor R1, an inductor L1 and a capacitor C1, a first end of the resistor R1 is used as an output end of the static electricity prevention circuit, a second end of the resistor R1 is electrically connected to one end of the inductor L1 and one end of the capacitor C1, respectively, the other end of the inductor L1 is electrically connected to the load, and the other end of the capacitor C1 is grounded.

5. The static elimination apparatus according to claim 3, wherein said surge absorption unit is an ESD discharge diode, one end of said ESD discharge diode is electrically connected to said first end of said low pass filter unit, and the other end of said ESD discharge diode is grounded.

6. The static elimination device according to claim 2, wherein said static electricity prevention circuit further comprises a static electricity suppressor, one end of said static electricity suppressor is used for electrically connecting to an I/O port in said static electricity prevention circuit, and the other end of said static electricity suppressor is grounded.

7. The static elimination apparatus according to claim 1, wherein the PCB board further comprises a connection terminal and a plurality of ESD absorbers, the connection terminal is provided with a plurality of connection pins, each of the connection pins is electrically connected to a first end of each of the ESD absorbers in a one-to-one correspondence, and a second end of each of the ESD absorbers is grounded.

8. The static elimination device according to claim 1, wherein there are two of said magnetic beads, and two of said magnetic beads are connected in series.

9. The static elimination device of claim 1, wherein the patch diode is an ESD protection diode.

10. The static elimination apparatus of claim 1, wherein the input voltage is an input voltage of + 5V.