CN214101916U

CN214101916U - Pad structure and PCB

Info

Publication number: CN214101916U
Application number: CN202120181499.6U
Authority: CN
Inventors: 张琳; 张善睿; 邓波; 景慎庆
Original assignee: Beigu Electronics Co ltd Shanghai Branch; North Valley Electronics Co ltd
Current assignee: Beigu Electronics Co ltd; Beigu Electronics Co ltd Shanghai Branch
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2021-08-31
Anticipated expiration: 2031-01-22

Abstract

The utility model provides a pad structure and PCB board, the pad structure includes: the circuit comprises a first bonding pad, a second bonding pad, a third bonding pad, a fourth bonding pad, a first sampling bonding pad, a second sampling bonding pad, a first sampling point and a second sampling point, wherein the first bonding pad and the second bonding pad are arranged oppositely; the first bonding pad and the third bonding pad are used for connecting one end of a chip resistor, and the second bonding pad and the fourth bonding pad are used for connecting the other end of the chip resistor; the first sampling pad is connected with the first sampling point through a first sampling wire, and the second sampling pad is connected with the second sampling point through a second sampling wire. The utility model provides a technical scheme has reduced the resistance in the pad to sampling circuit's influence, and then has improved the sampling precision.

Description

Pad structure and PCB

Technical Field

The utility model relates to a PCB board technical field, in particular to pad structure and PCB board.

Background

With the popularization of power electronic products, more stringent requirements are put forward on the design precision of the products. In order to realize the design of a product with higher precision, a sampling circuit is produced. The sampling circuit is divided into a current sampling circuit and a voltage sampling circuit. The current sampling is connected in series with a resistor with a smaller resistance value, and the voltage sampling is connected in parallel with a resistor with a larger resistance value. Taking a constant current source as an example, in order to keep the output current in a constant state, the current is collected at the output current as a reference, if the output current is large, the input end is automatically adjusted, and the output current is reduced; if the output is too low, the input end is automatically raised, so that the output current is raised, and the power supply is commonly used in power supply products, electronic products and electromechanical products.

The sampling resistor is generally classified into a chip resistor and a plug resistor. At present, a plurality of products adopt plug-in resistors for sampling, the pins of the plug-in resistors are long, and in addition, through hole welding pads of the welding pins on a circuit board cause that the sampling precision is not high. And the patch resistor with the precision of 0.1% is selected to replace the plug-in sampling resistor, a layer of solder paste is needed when the pad and the patch resistor are welded, the solder paste can cover the pad, and the sampling precision can still be influenced by the scheme because the solder paste has the resistor.

Therefore, it is desirable to provide a pad structure and a PCB to improve the sampling precision of the sampling circuit.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a pad structure and PCB board can improve sampling circuit's sampling precision.

In order to solve the technical problem, the utility model provides a pad structure, include:

the circuit comprises a first bonding pad, a second bonding pad, a third bonding pad, a fourth bonding pad, a first sampling bonding pad, a second sampling bonding pad, a first sampling point and a second sampling point, wherein the first bonding pad and the second bonding pad are arranged oppositely;

the first bonding pad and the third bonding pad are used for connecting one end of a chip resistor, and the second bonding pad and the fourth bonding pad are used for connecting the other end of the chip resistor;

the first sampling pad is connected with the first sampling point through a first sampling wire, and the second sampling pad is connected with the second sampling point through a second sampling wire.

Optionally, the first sampling pad is located between the first pad and the third pad, and the second sampling pad is located between the third pad and the fourth pad.

Optionally, the first sampling trace and the second sampling trace are in a differential trace form.

Optionally, the first pad, the second pad, the third pad, and the fourth pad are all rectangular.

Optionally, the lengths of the first bonding pad, the second bonding pad, the third bonding pad and the fourth bonding pad are all 3.3-3.7 mm, and the widths are all 1.7-1.9 mm.

Optionally, the first sampling pad and the second sampling pad are both rectangular.

Optionally, the lengths of the first sampling pad and the second sampling pad are both 3.3-3.7 mm, and the widths thereof are both 1.2-1.4 mm.

Optionally, the distance between the first pad and the first sampling pad and the distance between the third pad and the first sampling pad are 2.15-2.35 mm; the second pad and the fourth pad with the interval between the second sampling pad is 2.15 ~ 2.35 mm.

Optionally, the length error of the first sampling trace and the second sampling trace is 5 mil.

The utility model also provides a PCB board, include: a board main body, and the pad structure provided by the present invention; the PCB board still includes the tin cream, the tin cream set up in on first pad, second pad, third pad, fourth pad and first sampling pad and the second sampling pad, the thickness of tin cream is 0.13 ~ 0.15 mm.

Compared with the prior art, the technical scheme of the utility model following beneficial effect has:

1. the utility model provides a pad structure, through setting up relative first pad and the second pad that sets up, relative third pad and the fourth pad that sets up, relative first sampling pad and the second sampling pad that sets up reduce the influence of resistance to the sampling circuit precision in the pad, and then improve sampling circuit.

2. The utility model provides a PCB board is owing to have the utility model provides a pad structure for sampling circuit's precision obtains improving.

Drawings

Fig. 1 is a schematic structural diagram of a pad structure according to an embodiment of the present invention.

Wherein the reference numerals of figure 1 are as follows:

11-a first pad; 12-a second pad; 13-a third pad; 14-a fourth pad; 15-a first sampling pad; 16-a second sampling pad; 21-a first sampling trace; 22-a second sampling trace; and (6) performing screen printing.

Detailed Description

To make the objects, advantages and features of the present invention clearer, the pad structure and the PCB board provided by the present invention are further described in detail with reference to fig. 1. It should be noted that the drawings are simplified and have non-precise ratios, and are only used for convenience and clarity to assist in describing the embodiments of the present invention, and are not used for limiting the implementation of the present invention, so that the present invention has no technical essential significance, and any structural modification, ratio relationship change or size adjustment should still fall within the scope that the technical content disclosed by the present invention can cover without affecting the function and the achievable purpose of the present invention.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

An embodiment of the present invention provides a pad structure, refer to fig. 1, and can be seen from fig. 1, the pad structure includes: first and

second pads

11 and 12 disposed oppositely, third and

fourth pads

13 and 14 disposed oppositely, first and

second sampling pads

15 and 16 disposed oppositely, and first and second sampling points; the first pad 11 and the third pad 13 are used for connecting one end of a chip resistor, and the second pad 12 and the fourth pad 14 are used for connecting the other end of the chip resistor; the first sampling pad 15 is connected to the first sampling point via a first sampling trace 21, and the second sampling pad 16 is connected to the second sampling point via a second sampling trace 22.

The pad structure is described in detail below with reference to fig. 1:

the first pad 11, the second pad 12, the third pad 13 and the fourth pad 14 are pads of the same specification, the first sampling pad 15 and the second sampling pad 16 transmit sampling signals to the first sampling point and the second sampling point through the first sampling wire 21 and the second sampling wire 22 respectively and transmit the sampling signals to an amplifier, the pad is divided into three blocks in the embodiment, the influence of resistance of the pad on the sampling signals in the sampling circuit is reduced, and the sampling precision is improved.

Further, the first pad 11 and the third pad 13 are preferably disposed in parallel, and the second pad 12 and the fourth pad 14 are also disposed in parallel.

The first sampling pad 15 and the first pad 11 and the third pad 13 are mutually independent and mutually noninterference, the second sampling pad 16 and the second pad 12 and the fourth pad 14 are mutually independent and mutually noninterference, and the area of the first sampling pad 15 is smaller than the area of the first pad 11 and the third pad 13 in the pad structure, and the area of the second sampling pad 16 is smaller than the area of the second pad 12 and the fourth pad 14, so as to ensure the current capacity of the pad structure.

The first sampling trace 21 and the second sampling trace 22 are in the form of differential traces, because the two differential traces are well coupled, when there is noise interference outside, the two differential traces are almost simultaneously coupled to the two lines, and the receiving end only concerns the difference between the two signals, so the external common mode noise can be completely cancelled, and further the influence of the trace form on the sampling precision is reduced.

Preferably, first sampling pad 15 set up in first pad 11 with between second pad 12, second sampling pad 16 set up in third pad 13 with between fourth pad 14, can acquire the resistance size of sampling resistance more accurately, and then improve the sampling precision, in the utility model discloses a further embodiment, first sampling pad 15 can set up the top of first pad 11, also can set up the below of third pad 13, second sampling resistance can set up the top of third pad 13, also can set up the below of fourth pad 14.

First pad 11 the second pad 12 the third pad 13 and fourth pad 14 are the rectangle, because the pad structure is applied to in the sampling circuit, uses with the cooperation of a high accuracy paster sampling resistance, consequently adopts the pad of rectangle can make sampling paster resistance with the pad contact is more good, and then reduces because of the influence that welding problem caused the sampling precision.

In this embodiment, specifically, first pad 11 the second pad 12 the third pad 13 and the length of fourth pad 14 is 3.3 ~ 3.7mm, and the width is 1.7 ~ 1.9mm, first sampling pad 15 with second sampling pad 16 also is the rectangle, first sampling pad 15 with the length of second sampling pad 16 is 3.3 ~ 3.7mm, and the width is 1.2 ~ 1.4 mm. The distance between the first bonding pad 11 and the first sampling bonding pad 15 and the distance between the third bonding pad 13 and the first sampling bonding pad 15 are 2.15-2.35 mm; the second bonding pad 12 and the fourth bonding pad 14 with the interval between the second sampling bonding pad 16 is 2.15 ~ 2.35mm, prevents in welding process the tin cream on the first sampling bonding pad 15 with the tin cream on first bonding pad 11 or the third bonding pad 13 takes place to bond, and then leads to the resistance change in the sampling circuit, finally influences the sampling precision.

The pad structure further comprises a silk screen 30 of a device, wherein the silk screen 30 is used for ensuring that the chip resistor welded on the pad cannot interfere with other devices, and the size of the silk screen is slightly larger than that of the chip resistor.

The tolerance of the first sampling trace 21 and the second sampling trace 22 is 5 mil.

The pad structure provided by this embodiment takes the voltage sampling resistor as an example, and the precision can be improved by 0.3 to 0.4 mV.

To sum up, the utility model provides a pad structure, pad structure includes: the circuit comprises a first bonding pad, a second bonding pad, a third bonding pad, a fourth bonding pad, a first sampling bonding pad, a second sampling bonding pad, a first sampling point and a second sampling point, wherein the first bonding pad and the second bonding pad are arranged oppositely; the first sampling pad is positioned between the first pad and the third pad, and the second sampling pad is positioned between the third pad and the fourth pad; the first sampling pad is connected with the first sampling point through a first sampling wire, and the second sampling pad is connected with the second sampling point through a second sampling wire. The utility model provides a pad structure has reduced the resistance in the pad to sampling circuit's influence, and then has improved the sampling precision.

An embodiment of the utility model provides a PCB board, the PCB board includes: the board main part, and the utility model provides a pad structure.

The PCB board still includes the tin cream, the tin cream set up in on first pad, second pad, third pad, fourth pad and first sampling pad and the second sampling pad, the thickness of tin cream is 0.13 ~ 0.15 mm. The too thick resistance that can increase among the sampling circuit of thickness of tin cream increases the degree of difficulty among the welding process simultaneously, influences the precision of sampling, the too thin false welding that can lead to of thickness of tin cream leads to, causes contact failure.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and any modification and modification made by those skilled in the art according to the above disclosure are all within the scope of the claims.

Claims

1. A pad structure encapsulated in a board body of a PCB board, the pad structure comprising:

2. The pad structure of claim 1, wherein the first sampling pad is located between the first pad and the third pad, and the second sampling pad is located between the third pad and the fourth pad.

3. The pad structure of claim 1, wherein the first sampling trace and the second sampling trace are in a differential trace form.

4. The pad structure of claim 2, wherein the first pad, the second pad, the third pad, and the fourth pad are all rectangular.

5. The pad structure of claim 4, wherein the first pad, the second pad, the third pad, and the fourth pad are each 3.3-3.7 mm long and 1.7-1.9 mm wide.

6. The pad structure of claim 5, wherein the first sampling pad and the second sampling pad are each rectangular.

7. The pad structure of claim 6, wherein the first sampling pad and the second sampling pad each have a length of 3.3 to 3.7mm and a width of 1.2 to 1.4 mm.

8. The pad structure of claim 7, wherein a pitch between the first pad and the third pad and the first sampling pad is 2.15 to 2.35 mm; the second pad and the fourth pad with the interval between the second sampling pad is 2.15 ~ 2.35 mm.

9. The pad structure of claim 3, wherein the first sampling trace and the second sampling trace have a length error of 5 mils.

10. A PCB board, comprising: a board body, and a pad structure according to any one of claims 1 to 9; the PCB board still includes the tin cream, the tin cream set up in on first pad, second pad, third pad, fourth pad and first sampling pad and the second sampling pad, the thickness of tin cream is 0.13 ~ 0.15 mm.