A compensation design method for PCB discharge teeth of a planar transformer

Abstract

The present application relates to a kind of compensation design methods of planar transformer PCB discharge tooth, the method is as follows: after obtaining the original material of discharge tooth, first, the two sides of the discharge tooth are compensated, form two first compensation zones with the two sides of the discharge tooth respectively parallel;Then the tip of the intersection of the outer edge of the two first compensation zones is modified into arc part, and form the second compensation zone close to the tip of the discharge tooth;Finally, the bevel angle formed between the outer edge of the first compensation zone and the outer edge of the second compensation zone is designed into flat angle, forming third compensation zone.The present application is designed by three compensation zones, so that the compensation area is more uniform and smooth.So in the erosion processing, it can effectively avoid the situation of excessive etching or etching shortage, greatly improve the processing precision, ensure that the spacing between the tip of the discharge tooth meets the design tolerance, so as to improve product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of PCB discharge teeth, in particular, is especially related to a compensation design method of planar transformer PCB discharge teeth. BACKGROUND

[0002] The discharge teeth mainly act on the planar transformer PCB, also called discharge gap or spark gap. The discharge teeth are a pair of sharp angle triangles pointing to each other, which are made by using copper foil layer in the PCB wiring process. These triangles need to be placed on another layer of PCB components and cannot be covered by green oil and the like. During surge test or ESD test, high voltage will be generated at both ends of the common mode inductor, and arc will occur. If the distance between the surrounding devices is relatively close, the surrounding devices may be damaged.

[0003] Therefore, a discharge tube can be connected in parallel thereon to suppress its voltage. For example, a gas discharge tube is connected in parallel at both ends of the common mode inductor, which can thereby play an arc extinguishing effect. Although the suppression effect of the gas discharge tube is good, the cost is relatively high, so in most cases, a discharge tooth is placed at both ends of the common mode inductor during PCB design, so that the common mode inductor can discharge through the tip of the discharge tooth, which can reduce or even avoid discharging through other paths to protect the surrounding and subsequent devices.

[0004] Overall, the function of the discharge tooth on the PCB is to prevent damage to the circuit board and electronic components caused by static electricity, improve product quality and reliability, and meet relevant electronic industry standards. At present, the production line feedback of the discharge tooth made according to the existing design criteria will have the problems of discharge tooth spacing out of tolerance, difficult to control, and too large and irregular etching on the top of the discharge tooth, which will affect the tip discharge function of the discharge tooth and cause damage to the surrounding components, and cannot meet the quality and performance requirements. SUMMARY

[0005] Therefore, the present application provides a compensation design method of planar transformer PCB discharge teeth, which can improve the processing spacing tolerance accuracy of the discharge tooth and improve product quality.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] A compensation design method of planar transformer PCB discharge teeth, the method is as follows: after obtaining the original data of the discharge tooth, first, parallel compensation is performed on both sides of the discharge tooth to form two first compensation zones in which the edges of the two first compensation zones are parallel to the two sides of the discharge tooth; then the sharp part at the intersection of the outer edges of the two first compensation zones is modified into a circular arc part, and a second compensation zone close to the tip of the discharge tooth is formed; finally, the oblique angle formed between the outer edges of the first compensation zone and the outer edges of the second compensation zone is designed as a flat angle to form a third compensation zone.

[0008] In the above technical solution, the original document of the discharge tooth is taken as the design standard. In order to reduce the influence of the loss of the discharge tooth in the mechanical grinding and etching process on the precision of the discharge tooth, the original document needs to be compensated. The discharge tooth has a tip. First, the two sides connected to the tip of the discharge tooth are compensated in parallel by a certain value. Then, the tip part on one side of the tip of the discharge tooth generated in the first compensation is converted into a circular arc part. In this way, the existence of the sharp corner can be avoided. The circular arc part can effectively avoid the over-etching or under-etching of the side etching, so as to prevent the discharge tooth from being damaged. Finally, the oblique angle formed between the outer edge of the first compensation area and the outer edge of the second compensation area is designed into a flat angle. In this way, the entire design compensation area will not have a sharp corner or an angle. The compensation area is more uniform and smooth. In the etching process, the over-etching or under-etching can be effectively avoided. The processing precision is greatly improved. The distance between the tips of the discharge tooth meets the design tolerance, so as to improve the product quality.

[0009] Optionally, in a possible implementation, the modification method of the circular arc part is as follows:

[0010] S1: Set a compensation A value to determine the vertex of the circular arc part. The compensation A value is the distance between the tip of the discharge tooth and the vertex of the circular arc part.

[0011] S2: Set a compensation B value to determine two end points of the circular arc part. The compensation B value is the distance between the two end points of the circular arc part.

[0012] S3: Draw the circular arc part based on the vertex and the two end points of the circular arc part. The two end points of the circular arc part are symmetrically distributed on the opposite sides of the tip of the discharge tooth.

[0013] In the above technical solution, by setting the compensation A value, the distance between the tip of the discharge tooth and the vertex of the circular arc part can be accurately controlled. This serves as a reference. The discharge tooth can be prevented from being damaged due to the too small gap during etching. The distance between the tips of the two discharge teeth can also be prevented from being too small, which affects the use.

[0014] By setting the compensation B value and determining the two end points of the circular arc part, the symmetry of the circular arc part is ensured. The symmetric design not only improves the stability of the structure, but also ensures that the etching of the discharge tooth is more uniform. The vertex of the etched circular arc is closer to the tip of the discharge tooth, which reduces the influence of side etching on the discharge tooth.

[0015] In addition, the above-mentioned modification method is simple and clear, and only two compensation values, i.e., compensation A value and compensation B value, are required to determine the shape and position of the circular arc part. This makes it easy to adjust and optimize in actual production even if different processing requirements or equipment conditions are encountered.

[0016] Optionally, in a possible implementation, after the circular arc part is designed, the two end points of the circular arc part are extended horizontally until connected with the outer edges of the two first compensation areas.

[0017] In the above technical solution, the two end points of the circular arc part are connected with the outer edges of the first compensation area through horizontal line segments, which serves to complete the second compensation area so as to form a closed whole, avoiding the occurrence of breakpoints and missing areas, so as to ensure the integrity of the second compensation area.

[0018] Optionally, in a possible implementation, after the circular arc part is designed, the two end points of the circular arc part are extended horizontally until connected with the outer edges of the two first compensation areas, and then the part of the first compensation area that coincides with the second compensation area is removed.

[0019] In the above technical solution, the two end points of the circular arc part are further extended until connected with the outer edges of the discharge teeth after being extended to the outer edges of the first compensation area, which mainly serves to better distinguish the boundary between the first compensation area and the second compensation area, facilitating the design and understanding of the designer and reducing the design difficulty.

[0020] Optionally, in a possible implementation, the distance between the outer edge of the first compensation area and the edge of the discharge teeth is set as a compensation C value, and the compensation C value is half of the criterion-defined PAD compensation value in the original data.

[0021] In the above technical solution, the criterion-defined PAD compensation value is used as a standard value to define the sizes of the compensation A value, the compensation B value and the compensation C value, and the compensation C value is a standard value used in the discharge teeth processing process, which can achieve an ideal effect of the discharge teeth processing and use.

[0022] Optionally, in a possible implementation, the size of the compensation A value is 1.5 mil-7.5 mil.

[0023] In the above technical solution, the specifications of the discharge teeth required by different copper thicknesses of PCBs are also different, and flexible design needs to be performed according to the corresponding types of PCBs. For example, the compensation A values of the discharge teeth corresponding to the copper thicknesses of Hoz, 1oz, 1.5oz, 2oz, 2.5oz and 3oz are 1.5 mil, 3.0 mil, 4.0 mil, 5.0 mil, 6.5 mil and 7.5 mil, respectively.

[0024] Optionally, in a possible implementation, the compensation B value is 3.0 mil-9.0 mil.

[0025] In the above technical solution, the specifications of the discharge teeth required by PCBs with different copper thicknesses are also different, and flexible design needs to be made for the corresponding types of PCBs, such as the discharge tooth compensation B values corresponding to the copper thicknesses of Hoz, 1oz, 1.5oz, 2oz, 2.5oz and 3oz are 3.0 mil, 4.0 mil, 6.5 mil, 7.0 mil, 8.0 mil and 9.0 mil respectively.

[0026] Optionally, in a possible implementation, the design method of the flat angle is as follows: a line segment is drawn, and the two ends of the line segment are tangent to the outer edge of the first compensation area and the outer edge of the circular arc part respectively.

[0027] In the above technical solution, the design of the flat angle can be realized by simple line drawing operation, without complex calculation or measurement, greatly simplifying the design process, improving the design efficiency, and quickly and effectively repairing the bevel formed between the outer edge of the first compensation area and the outer edge of the circular arc part, to improve the effect of subsequent etching processing.

[0028] Optionally, in a possible implementation, the discharge teeth are a plurality of adjacent and continuous ones.

[0029] In the above technical solution, the plurality of adjacent and continuous discharge teeth can form a continuous discharge path, thereby increasing the effective area of discharge, making the discharge more uniform, improving the discharge efficiency, and helping to improve the performance of the equipment in applications requiring discharge processing. In addition, since the discharge teeth are continuously arranged, they can jointly share the heat and pressure in the discharge process, avoiding local overheating or damage caused by single-point discharge.

[0030] Compared with the prior art, the beneficial effects of the present application are:

[0031] The compensation design method of the planar transformer PCB discharge teeth of the present application first compensates the two sides connected by the tip of the discharge tooth by a certain value, then converts the sharp part generated on the side of the tip of the discharge tooth in the first compensation into a circular arc part, and finally modifies the graphic corner into a flat angle, so that the compensation area is more uniform and smooth. In this way, excessive etching or insufficient etching can be effectively avoided during etching processing, greatly improving the processing precision and ensuring that the spacing between the tips of the discharge teeth meets the design tolerance, thereby improving the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and other related drawings can also be obtained by those of ordinary skill in the art without creative labor on the basis of these drawings.

[0033] Figure 1 The flowchart of the compensation design of the discharge teeth of an embodiment.

[0034] Figure 2 The etching effect diagram of the discharge teeth of an embodiment. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0036] Therefore, the detailed description of the embodiments of the present application provided in the drawings below is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art on the basis of the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0037] Reference Figure 1 The present embodiment provides a compensation design method of the PCB discharge teeth of a planar transformer. The original data of the discharge teeth is used as the design standard. In order to reduce the influence of the loss of the discharge teeth in the mechanical grinding, etching and processing on the precision of the discharge teeth, the original data needs to be compensated and designed. The specific design method is as follows:

[0038] After obtaining the original data of the discharge teeth, first, the two sides of the discharge teeth are compensated in parallel to form two first compensation zones in which the two edges are parallel to the two sides of the discharge teeth. The discharge teeth have a sharp end, and the two sides of the discharge teeth extend outward at a certain angle from the sharp end as the starting point. The two first compensation zones intersect at the sharp end of the discharge teeth to form a region with a sharp corner, hereinafter referred to as the sharp part.

[0039] Then the tip at the intersection of the outer edges of the two first compensation zones is modified into a circular arc portion, and a second compensation zone is formed near the tip of the discharge tooth. The presence of the tip on the one hand will lead to an excessively large compensation area, affecting the machining tolerance; on the other hand, due to the fact that the discharge tooth is usually located in the vacant area of the base material, it is affected by the etching of the etching solution and the pool effect, which will cause the top of the discharge tooth to be excessively eroded or excessively small, resulting in an excessively large or small spacing, and the tip of the discharge tooth will be deformed irregularly. The modification into a circular arc portion can effectively solve the above problems.

[0040] Finally, the bevel angle between the outer edges of the first compensation zone and the outer edges of the second compensation zone is designed into a flat angle to form a third compensation zone. The bevel angle is the corner area formed when the outer edges intersect during the design of the first compensation zone and the second compensation zone. By further compensating the bevel angle into a flat angle, the entire design compensation area will not have any sharp corners or corner areas, and the compensation area will be more uniform and smooth. This can effectively avoid over-etching or under-etching during the etching process, greatly improving the processing precision and ensuring that the spacing between the tips of the discharge teeth meets the design tolerance, thereby improving product quality.

[0041] In this embodiment, a PCB board with 1.5oz of base copper is taken as an example, and the modification method of the circular arc portion is as follows:

[0042] S1: Set the compensation A value to determine the vertex of the circular arc portion. The compensation A value is the distance between the tip of the discharge tooth and the vertex of the circular arc portion. For a PCB board with 1.5oz of base copper, the compensation A value is set to 4.0mil.

[0043] By setting the compensation A value, the distance between the tip of the discharge tooth and the vertex of the circular arc portion can be accurately controlled, which serves as a reference. This can prevent the discharge tooth from being damaged due to a too small gap during etching, and can also prevent the spacing between the tips of the two relative discharge teeth from being too small, which affects the use.

[0044] S2: Set the compensation B value to determine the two endpoints of the circular arc portion. The compensation B value is the distance between the two endpoints of the circular arc portion. For a PCB board with 1.5oz of base copper, the compensation B value is set to 6.5mil. In addition, the line connecting the two endpoints of the circular arc portion is perpendicular to the angle bisector of the discharge tooth, i.e. the circular arc portion is symmetrically distributed about the angle bisector of the discharge tooth.

[0045] By setting the compensation B value and determining the two endpoints of the circular arc portion, the symmetry of the circular arc portion is ensured. Symmetrical design not only improves the stability of the structure, but also ensures that the etching of the discharge tooth is more uniform, so that the vertex of the etched circular arc is closer to the tip of the discharge tooth, reducing the influence of side etching on the discharge tooth.

[0046] S3: Draw the arcuate portion with the two end points of the arcuate portion symmetrically distributed on the opposite sides of the discharge tooth tip end as the reference.

[0047] The modification method of the arcuate portion in this embodiment is simple and clear, and only two compensation values, i.e., compensation A value and compensation B value, are needed to determine the shape and position of the arcuate portion. This makes it easy to adjust and optimize even in the face of different processing requirements or equipment conditions in actual production.

[0048] In this embodiment, after the arcuate portion is designed, the two end points of the arcuate portion are extended horizontally until they are connected with the outer edges of the two first compensation areas. The two end points of the arcuate portion are connected with the outer edges of the first compensation area by horizontal line segments, which serves to complete the second compensation area to form a closed whole, avoiding the occurrence of breakpoints and missing areas, so as to ensure the integrity of the second compensation area.

[0049] In addition, as another embodiment, after the arcuate portion is designed, the two end points of the arcuate portion are extended horizontally until they are connected with the two outer edges of the discharge tooth, and then the part of the first compensation area that overlaps with the second compensation area is removed. After the two end points of the arcuate portion are extended to the outer edges of the first compensation area, they are further extended to the two outer edges of the discharge tooth, which mainly serves to better distinguish the boundary between the first compensation area and the second compensation area, facilitating the design and understanding of the designer and reducing the design difficulty.

[0050] In this embodiment, the distance between the outer edge of the first compensation area and the edge of the discharge tooth is set as compensation C value, and the compensation C value is half of the criterion defined PAD compensation value in the original data. In this embodiment, the compensation C value of the PCB with 1.5oz of copper is 2.0mil, that is, the criterion defined PAD compensation value is 4.0mil.

[0051] Specifically, the criterion defined PAD compensation value is used as a standard value to determine the sizes of the compensation A value, the compensation B value and the compensation C value, and the compensation C value is a standard value used in the processing of the discharge tooth, which can achieve an ideal effect in the processing and use of the discharge tooth.

[0052] In this embodiment, the size of the compensation A value is 1.5mil-7.5mil. The specifications of the discharge tooth required by PCBs with different thicknesses of copper are also different, and flexible design needs to be made for corresponding types of PCBs. For example, the compensation A values of the discharge tooth corresponding to the thicknesses of 1.5oz, 1oz, 1.5oz, 2oz, 2.5oz and 3oz of copper are 1.5mil, 3.0mil, 4.0mil, 5.0mil, 6.5mil and 7.5mil, respectively.

[0053] In this embodiment, the size of the compensation B value is 3.0 mil-9.0 mil. Corresponding to the compensation A value, the required discharge tooth gauge of PCBs with different copper thicknesses will also be different, and flexible design needs to be made for the corresponding type of PCB, such as the discharge tooth compensation B values corresponding to the copper thicknesses of Hoz, 1oz, 1.5oz, 2oz, 2.5oz and 3oz are 3.0 mil, 4.0 mil, 6.5 mil, 7.0 mil, 8.0 mil and 9.0 mil respectively.

[0054] To set the tolerance of the distance between the two discharge tooth top parts within 0.05-0.15mm, the specific set compensation A value and compensation B value are shown in the following table.

[0055]

[0056] In this embodiment, the design method of the flat angle is as follows: draw a line segment, and the two ends of the line segment are tangent to the outer edge of the first compensation area and the outer edge of the arc part respectively.

[0057] The design of the flat angle can be realized by simple line drawing operation, without complex calculation or measurement, greatly simplifying the design process, improving the design efficiency, and quickly and effectively repairing the bevel formed between the outer edge of the first compensation area and the outer edge of the arc part, to improve the effect of subsequent etching processing.

[0058] Please refer to Figure 2 Taking a PCB board with copper thickness of 1.5oz as an example, the compensation A value is designed as 4.0mil, the compensation B value is 6.5mil, and the compensation C value is 2.0mil. After production and processing, the etching burr (i.e. the structure formed after etching of the compensation area, which is part of the final discharge tooth) is 0.063mm, which can be controlled within 0.1mm, and the discharge tooth distance can be effectively controlled within the required range, meeting the quality and performance requirements of the discharge tooth.

[0059] In this embodiment, the discharge tooth is a plurality of adjacent and continuous discharge teeth. The plurality of adjacent and continuous discharge teeth can form a continuous discharge path, thereby increasing the effective area of discharge, making the discharge more uniform, improving the discharge efficiency, and helping to improve the performance of the equipment in applications requiring discharge processing. In addition, since the discharge teeth are continuously arranged, they can jointly share the heat and pressure in the discharge process, avoiding local overheating or damage caused by single-point discharge.

[0060] It should be noted that when the discharge tooth is processed, the outer layer etching discharge tooth distance control requirement can be set as follows.

[0061] As the discharge tooth spacing is required to be 5.2±0.1mm (5.1-5.3mm), the etching is controlled according to the lower limit 5.1-5.15 of the median, so as to ensure that the spacing is controlled near the median 5.15-5.25mm after the mechanical brushing and chemical etching loss in the pretreatment process, and the ideal control value is reached.

[0062] The discharge of the discharge tooth is mainly the indirect contact discharge of the burr top end, and the copper surface on the upper amplitude of the discharge tooth cannot be controlled according to the normal requirement, and the spacing between the top ends of the lower amplitudes (burr) on both sides of the discharge tooth is controlled.

[0063] In addition, different thicknesses of the bottom copper can be appropriately optimized on the basis of the present compensation standard if there are special requirements, so as to finally meet the requirements and performance requirements.

[0064] In the description of the present application, it should be understood that the terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0065] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0066] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A compensation design method of a planar transformer PCB discharge tooth, characterized in that, The method is as follows: After obtaining the original data of the discharge teeth, first, parallel compensation is performed on the two sides of the discharge teeth to form two first compensation zones whose two edges are parallel to the two sides of the discharge teeth; then the sharp part at the intersection of the outer edges of the two first compensation zones is modified into a circular arc part, and a second compensation zone close to the tip of the discharge teeth is formed; finally, the oblique angle formed between the outer edge of the first compensation zone and the outer edge of the second compensation zone is designed as a flat angle to form a third compensation zone; The modification method of the circular arc part is as follows: S1: Set compensation A value to determine the vertex of the circular arc part, and the compensation A value is the distance between the tip of the discharge teeth and the vertex of the circular arc part; S2: Set compensation B value to determine the two endpoints of the circular arc part, and the compensation B value is the distance between the two endpoints of the circular arc part; S3: Draw the circular arc part with the vertex and two endpoints of the circular arc part as the reference, and the two endpoints of the circular arc part are symmetrically distributed on the opposite sides of the tip of the discharge teeth.

2. The planar transformer PCB discharge tooth compensation design method of claim 1, wherein, After designing the circular arc part, the two endpoints of the circular arc part are extended horizontally until they are connected with the outer edges of the two first compensation zones.

3. The planar transformer PCB discharge tooth compensation design method of claim 1, wherein, After designing the circular arc part, the two endpoints of the circular arc part are extended horizontally until they are connected with the two outer edges of the discharge teeth, and then the part of the first compensation zone that coincides with the second compensation zone is removed.

4. The planar transformer PCB discharge tooth compensation design method of claim 1, wherein, The distance between the outer edge of the first compensation zone and the edge of the discharge teeth is set as compensation C value, and the compensation C value is half of the PAD compensation value defined in the original data.

5. The planar transformer PCB discharge tooth compensation design method of claim 4, wherein, The size of the compensation A value is 1.5 mil-7.5 mil.

6. The planar transformer PCB discharge tooth compensation design method of claim 4, wherein, The size of the compensation B value is 3.0 mil-9.0 mil.

7. The planar transformer PCB discharge tooth compensation design method of claim 1, wherein, The design method of the flat angle is as follows: Draw a line segment, and the two ends of the line segment are tangent to the outer edge of the first compensation zone and the outer edge of the circular arc part, respectively.

8. The planar transformer PCB discharge tooth compensation design method according to any one of claims 1-7, wherein, The discharge teeth are a plurality of adjacent and continuous ones.

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