Convergence metal sheet and circuit board thereof

Abstract

The embodiment of the utility model provides a bus metal sheet and a circuit board thereof. The bus metal sheet includes: a first portion having a first dimension in a length direction and a second dimension in a width direction; the N second parts are arranged at intervals; each second part extends outwards along the width direction from one edge of the first part to form a tail end deviating from the first part; the end of the second portion is configured to: establish a physical connection with the circuit board allowing current to pass through; the distance between the tail end of the second part and one edge of the first part in the width direction is a third size; the third size is determined by the thickness of the circuit board. The confluence metal sheet has a better current sharing effect, and the confluence metal sheet vertically fixed on the surface of the circuit board can increase the air contact area, thereby being beneficial to the heat dissipation of the power device, and effectively avoiding the excessive occupation of the area of the PCB.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit boards, in particular to a busbar metal sheet and a circuit board thereof. Background Art

[0002] As electronic products are widely used, more and more high-power devices (such as diodes, MOS tubes and IGBTs) are used more and more frequently. Generally, multiple high-power devices connected in parallel on a printed circuit board (PCB) will have different degrees of current inconsistency.

[0003] In particular, when the high-power devices in parallel are also connected in series with small pads of other devices (current sensing resistors, locking terminals and wire pads, etc.), the loop impedance difference of the high-power devices in parallel will increase accordingly, exacerbating the degree of current inconsistency.

[0004] The current inconsistency between parallel high-power devices will have a significant negative impact on the life, performance and reliability of electronic products. Therefore, it is always expected to reduce the degree of current inconsistency between parallel high-power devices as much as possible to ensure equal distribution of current.

[0005] There are some solutions to reduce the degree of current inconsistency. Figure 1 As shown, among the high-power devices arranged on one side of the PCB board, the current sharing effect can be achieved by increasing the spacing D1 of the series connection between multiple parallel power devices Q and the confluence point P, and using a large area of ​​copper to match the impedance. If it is necessary to apply it to a double-sided PCB board, a via array can be added in the spacing of the above series connection. However, this method significantly increases the PCB material cost and unnecessary impedance loss.

[0006] like Figure 2 As shown, one or more rectangular metal sheets M can also be surface mounted on the surface of the PCB board to connect the conduction path between the three power devices Q and the confluence point P, thereby reducing the PCB copper foil impedance and achieving the effect of current sharing.

[0007] However, when there are a large number of power devices connected in parallel and the length of the metal sheet is not enough to cover them, it is necessary to use multiple metal sheets in series (for example, Figure 2 As shown in the figure, the large current between the two pieces needs to flow from one of the metal pieces back to the PCB copper foil before flowing to the other metal piece, which significantly reduces the current sharing effect of the metal pieces.

[0008] Moreover, the length of the metal sheet is also limited by the processing technology. When the length of the metal sheet exceeds a certain value, it is easy to deform (warp) during the processing, making it impossible to achieve surface mounting.

[0009] In addition, when applied to the double-sided arrangement of power devices, the surface mounted metal sheet will also occupy the area of ​​the PCB board, significantly reducing the area on the PCB board where vias can be set (the area covered by the black metal sheet cannot be used), and the ideal current sharing effect cannot be achieved. Utility Model Content

[0010] The utility model provides a busbar metal sheet and a circuit board thereof, aiming to solve at least one defect of an existing current balancing solution for reducing the degree of current inconsistency between a plurality of parallel-connected power devices.

[0011] In the first aspect, the utility model provides a busbar metal sheet. The busbar metal sheet comprises: a first part; the first part has a first dimension in the length direction, and the first part has a second dimension in the width direction; N second parts arranged at intervals; N is a positive integer; each second part extends outward from one edge of the first part along the width direction to form an end away from the first part; the end of the second part is configured to: establish a physical connection with a circuit board to allow current to pass; wherein the distance between the end of the second part and one edge of the first part in the width direction is a third dimension; the third dimension is determined by the thickness of the circuit board.

[0012] In some embodiments, the thickness of the circuit board and the third dimension satisfy the following formula: T+2mm≥H1; wherein T is the thickness of the circuit board; H1 is the third dimension

[0013] In some embodiments, the second dimension is greater than or equal to 3.5 mm.

[0014] In some embodiments, the end of the second part has a fourth dimension in the width direction; in the width direction, the interval between two adjacent second parts also has the fourth dimension; wherein the first dimension and the fourth dimension satisfy the following formula: L1=L2*2N; wherein L1 is the first dimension; L2 is the fourth dimension.

[0015] In some embodiments, the N second portions and the first portion form complementary edges of the busbar metal sheet, so that two busbar metal sheets can be spliced ​​to form a regular shape.

[0016] In some embodiments, the regular shape is a rectangle.

[0017] In some embodiments, the first portion is rectangular; the N second portions are rectangular; wherein one length edge of one of the N second portions is flush with one width edge of the first portion to form a continuous edge of the busbar metal sheet.

[0018] In some embodiments, the bus metal sheet has a thickness greater than or equal to 2 mm.

[0019] In a second aspect, the utility model provides a circuit board. The circuit board comprises: a substrate; a busbar is provided on the substrate; N power devices; the N power devices are arranged on one surface of the substrate; the busbar metal sheet as described above; wherein the busbar metal sheet is fixed upright on the substrate to form a physical connection between each power device and the busbar; the physical connection allows current to pass through.

[0020] In a third aspect, the utility model provides a circuit board. The circuit board comprises: a substrate; the substrate has a first surface and a second surface facing away from each other; a busbar is arranged on the first surface or the second surface; N first power devices; the first power devices are arranged on the first surface of the substrate; N second power devices; the second power devices are arranged on the second surface of the substrate; the busbar metal sheet as described above; wherein the second part of the busbar metal sheet passes through the substrate to form a physical connection between the first power device and the second power device; at least a part of the busbar metal sheet also establishes a physical connection with the busbar; the physical connection allows current to pass.

[0021] At least one beneficial effect of the busbar metal sheet and circuit board provided by the embodiment of the utility model is that compared with the traditional PCB copper foil (usually 2oz=35um) or surface mounted metal sheet, a busbar metal sheet with a higher thickness (for example, greater than 2mm) can be easily manufactured during manufacturing so that the impedance of the current path between each high-power device and the busbar is nearly equal. Even when the busbar is offset from the center position, the busbar metal sheet can still play a very important role.

[0022] Moreover, the busbar metal sheet fixed vertically on the surface of the circuit board can increase the air contact area, which is beneficial to the heat dissipation of the power device and can effectively avoid excessive occupation of the PCB board area (relative to the current equalization solution of the surface mounted metal sheet). BRIEF DESCRIPTION OF THE DRAWINGS

[0023] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent the same elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0024] Figure 1 It is a schematic diagram of the structure of an existing circuit board, showing a situation where three power devices are arranged on the circuit board;

[0025] Figure 2 It is a schematic diagram of the structure of an existing circuit board, showing a situation where two metal sheets are mounted on the surface of the circuit board;

[0026] Figure 3 A schematic diagram of the structure of a busbar metal sheet provided in an embodiment of the utility model;

[0027] Figure 4 A schematic diagram of a busbar metal sheet provided in an embodiment of the utility model being mounted on a circuit board, showing a side view of the busbar metal sheet;

[0028] Figure 5 A schematic diagram of a busbar metal sheet provided in an embodiment of the utility model being assembled on a circuit board, showing a top view of the busbar metal sheet;

[0029] Figure 6 A schematic diagram of the segmentation of the busbar metal sheet provided in the embodiment of the utility model shows the situation where two busbar metal sheets are complementary and combined to form a rectangle;

[0030] Figure 7 A schematic diagram of a circuit board provided in an embodiment of the utility model.

[0031] Reference numerals:

[0032] Q: power device; P: busbar; M: surface mount metal sheet; 20: substrate;

[0033] 10: busbar metal sheet; 11: first part; 12: second part; 13: end;

[0034] x: length direction; y: width direction; L1: first dimension; L2: fourth dimension;

[0035] H1: second dimension; H2: third dimension; W: thickness of busbar metal sheet. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with specific embodiments. It should be emphasized that the following description is merely illustrative and is not intended to limit the scope and application of the present invention.

[0037] It should be noted that, unless otherwise clearly specified and limited, the terms "thickness direction", "plug-in" and the like used in this specification to indicate orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The terms such as "installation", "fitting", "connection" and "fixation" should be understood in a broad sense. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; "fixation" can be bolted, snap-fitted or glued; the terms "first", "second", "third", "fourth", "fifth" and "sixth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated; thus, the features defined as "first", "second", "third", "fourth", "fifth" and "sixth" may explicitly or implicitly include one or more of the features; "multiple" or "several" means two or more; in addition, "and / or" includes any and all combinations of one or more related listed items; for ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to specific circumstances.

[0038] In order to make the purpose, technical solutions and advantages of the utility model clearer, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] The term "power device" refers to electronic devices used to process and control high voltage and high current. They can withstand high load voltage and current and provide high efficiency and stability. For example, diodes, MOS tubes and IGBTs.

[0040] The term "pierce welding" refers to a form of metal sheet fastening in which a high current and pressure are applied to cause the upper metal material to penetrate the lower material and form a physical connection between the metals at the penetration point, allowing the flow of electric current.

[0041] The term "current sharing" refers to the situation where each power device carries the same or similar current when multiple power devices are used in parallel. This can be achieved through circuit and / or structural design to ensure balanced operation of the system and improve overall reliability.

[0042] The term "physical connection" refers to a structure in which two or more components are physically and physically connected to each other.

[0043] Figure 3Schematic diagram of a busbar metal sheet provided in an embodiment of the utility model. Figure 3 As shown, the busbar metal sheet 10 includes a first portion 11 and N second portions 12 arranged at intervals.

[0044] The "first portion 11" refers to a portion of the busbar structure. It has a first dimension L1 in the length direction x and a second dimension H1 in the width direction y. The "second portion 12" is another portion of the busbar structure. It extends outward from one edge of the first portion 11 along the width direction y to form an end 13 away from the first portion 11.

[0045] In this article, for the convenience of description, the complete busbar metal sheet is divided into a "first part 11" and a "second part 12". However, such division is not used to limit the actual form of the busbar metal sheet. Specifically, the busbar metal sheet can be a continuous metal sheet formed in one piece, or it can be assembled by one or more metal parts separated from each other through a suitable fixed connection method (for example, welding or bonding), which is not specifically limited here.

[0046] Please continue reading Figure 3 The N second portions 12 can be arranged at intervals according to a set pitch, so as to form a plurality of continuous depressions and protrusions on a portion of the edge of the busbar metal sheet.

[0047] Wherein, N is a positive integer, which can be determined by the number of power devices that need to be connected to the busbar metal sheet. For example, when there are three power devices that need to be connected to the busbar, the value of N is 3.

[0048] In actual application, Figure 4 As shown, the busbar metal sheet 10 is vertically arranged substantially relative to the surface of the substrate 20. The second portion 12 can be fixed by welding such as through-hole welding, so that a physical connection is established between the end 13 of the second portion 12 and / or at least a portion of the second portion 12 and the circuit board to allow current to pass.

[0049] Please continue reading Figure 3 In this document, the distance between the end 13 of the second portion 12 and one of the edges E1 of the first portion 11 in the width direction y is referred to as a “third dimension H2”. In other words, the third dimension H2 represents the length of the second portion 12.

[0050] As described in the above practical application, since the second portion 12 is the portion of the busbar metal sheet inserted into the circuit board, the third dimension H2 can be determined by the thickness of the circuit board, and a certain difference is appropriately maintained between the third dimension H2 and the thickness of the circuit board, so as to ensure that when the busbar metal sheet is vertically welded and fixed on the circuit board, sufficient depth can be provided to avoid unexpected cold solder joints and solder wrapping.

[0051] Preferably, the difference between the third dimension H2 and the thickness of the circuit board may be at least greater than or equal to 2 mm, which can provide sufficient solder penetration depth to ensure that cold solder joints or solder joints are not prone to occur even when the soldering area of ​​the component is large.

[0052] In some embodiments, please refer to Figure 4 The above-mentioned bus metal sheet can be a plate-shaped component with a uniform thickness W. The thickness W is set to be greater than or equal to 2 mm, so that the impedance between each power device and the bus point is nearly equal, which can play a good effect even when there is a large offset between the bus point and the center position.

[0053] The first part of the busbar metal sheet can actually be considered as the main structure of the entire metal sheet. Preferably, in order to ensure that the busbar metal sheet has sufficient strength, the second dimension H2 can be appropriately set to be greater than or equal to 3.5 mm, thereby effectively avoiding serious deformation of the busbar metal sheet and thus affecting the performance of the electronic product.

[0054] In some embodiments, please refer to Figure 3 , the width of the end 13 of the second portion 12 in the length direction x can be referred to as the "fourth dimension L2". At the same time, the N second portions 12 are arranged in an evenly spaced manner, and the interval between any two adjacent second portions is also the fourth dimension L2 (i.e., equal to the width of the end 13 of the second portion). Therefore, the first dimension L1 and the fourth dimension L2 satisfy the following formula: L1 = L2*2N.

[0055] Preferably, the plurality of second portions 12 and the first portion 11 form complementary edges of the busbar metal sheet, so that the two busbar metal sheets can be spliced ​​to form a regular shape.

[0056] Here, “complementary edges” means that at least a portion of the edges of the busbar metal sheets have a specific shape design, so that the two busbar metal sheets can fit closely with each other when combined.

[0057] In other words, based on the design of the complementary edges, two identical busbar metal sheets always have at least one combination mode, so that after the two identical busbar metal sheets are combined with each other, a larger regular shape can be formed.

[0058] "Regular shape" means a shape with certain symmetry, following specific mathematical rules and patterns. For example, a regular polygon or a rectangle. Preferably, the regular shape can be a rectangle with a specific length and width.

[0059] The design of the complementary edges can arrange the busbar metal sheets in a very compact manner with almost no gaps in the cutting layout of the raw material, thereby reducing unused materials.

[0060] For example, Figure 6 As shown, in a rectangular plate-shaped raw material, multiple busbar metal sheets can be cut out as much as possible, while reducing the proportion of waste generated after cutting to the raw material, thereby improving the utilization rate of the raw materials and effectively saving processing costs.

[0061] In some embodiments, please refer to Figure 6 The first part 11 and the second part 12 are both configured as rectangles. A length edge of the second part 12 is flush with a width edge of the first part 11 to form a continuous edge E2 of the busbar metal sheet.

[0062] Such a design can ensure that when N takes any value, the busbar metal sheet has the complementary edges mentioned above and can be combined with another identical busbar metal sheet to form a larger rectangle (the length of the rectangle is the first dimension L1 mentioned above, and its width is the sum of the second dimension h1 and the two third dimensions h2).

[0063] Based on the busbar metal sheet provided in the embodiment of the utility model, the embodiment of the utility model further provides a circuit board.

[0064] Figure 7 A schematic diagram of a circuit board provided in an embodiment of the present application. For example, Figure 7 The circuit board shown in the figure shows the situation of setting up three power devices Q. Figure 3 To match the three power devices Q shown, the number of the second parts of the bus metal sheet 10 is also set to 3. Of course, more or fewer power devices can be selectively set according to actual needs.

[0065] like Figure 7 As shown, the circuit board includes: a substrate 20 , a plurality of power devices Q and a busbar metal sheet 10 .

[0066] The substrate 20 is provided with a confluence point P. A plurality of power devices Q are arranged on one surface of the substrate and connected in parallel.

[0067] The bus metal sheet 10 can be fixed on the substrate 20 by a welding method called "through-hole welding". Each second portion 12 of the bus metal sheet 10 can establish a physical connection with a power device Q to allow current to pass, thereby achieving parallel connection of three power devices.

[0068] Furthermore, the bus metal sheet 10 can also establish a physical connection with the bus point P to allow current to pass through, thereby achieving an electrical connection between the power device Q and the bus point P.

[0069] In other embodiments, based on the above-mentioned fixing form of “perforated welding”, the busbar metal sheet 10 can also be applied to the scenario where power devices are arranged on both sides of the circuit board.

[0070] For ease of description, two surfaces of the circuit board facing away from each other may be referred to as a “first surface” and a “second surface”, and the power devices respectively arranged on the first surface and the second surface are respectively referred to as a “first power device” and a “second power device”.

[0071] A busbar may be provided on one of the first surface or the second surface of the substrate, and the busbar metal sheet is arranged on the substrate surface where the busbar is located.

[0072] Therefore, based on the penetration welding process of the bus metal sheet, the bus metal sheet passes through the second portion of the substrate to form a physical connection between the first power device and the second power device, allowing current to pass.

[0073] Furthermore, an electrical connection among the first power device, the second power device and the bus point is achieved through a physical connection established between the bus metal sheet and the bus point that allows current to pass.

[0074] In summary, the busbar metal sheet provided in the embodiment of the utility model can provide a metal sheet welding point connected to the parallel pins of the power device. Compared with the thickness of the PCB copper foil (usually 2oz=35um), the busbar metal sheet can easily achieve a thickness of 2mm or more in terms of technology. Such a sufficient metal sheet thickness can ensure that the impedance of the power path from each power device to the busbar point is nearly equal, and even when there is a significant offset between the busbar point and the center position of the busbar metal sheet, there will be no significant impedance difference.

[0075] Furthermore, the busbar metal sheets are designed to be complementary, and can be complementary combined to form a regular shape when n takes any value, thereby avoiding the generation of waste as much as possible and saving costs.

[0076] In addition, the bus metal sheet is fixed on the substrate by perforation welding in an upright state relative to the substrate surface along the width direction. The PCB board area occupied by it (slightly larger than the product of the thickness of the bus metal sheet and the first dimension) can be significantly reduced compared to the surface mounting metal sheet method.

[0077] The metal sheet in an upright state relative to the substrate surface can also increase the contact area with the air, which is beneficial to improving the heat dissipation effect of the power device.

[0078] Moreover, the through-hole welding provides a structural method of penetrating the substrate, so that the second part of the busbar metal sheet can further establish a physical connection with the power device on the other surface of the substrate, thereby being applied to the power devices on both surfaces for current sharing, effectively saving the PCB board area.

[0079] The above contents are further detailed descriptions of the present invention in combination with specific / preferred implementations, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A busbar metal sheet, characterized in that: include: Part I; The first portion has a first dimension in a length direction, and the first portion has a second dimension in a width direction; The second part of N interval settings; N is a positive integer; Each of the second parts extends outwardly from one edge of the first part along the width direction to form an end facing away from the first part; The end of the second portion is configured to: establish a physical connection with the circuit board to allow current to flow; Wherein, the distance between the end of the second part and one edge of the first part in the width direction is a third dimension; The third dimension is determined by the thickness of the circuit board.

2. The bus metal sheet according to claim 1, characterized in that: The thickness of the circuit board and the third dimension satisfy the following formula: T+2mm≥H2; Wherein, T is the thickness of the circuit board; H2 is the third dimension.

3. The bus metal sheet according to claim 1, characterized in that: The second size is greater than or equal to 3.5 mm.

4. The bus metal sheet according to claim 1, characterized in that: The end of the second portion has a fourth dimension in the length direction; In the length direction, the interval between two adjacent second parts also has the fourth size; The first size and the fourth size satisfy the following formula: L1=L2*2N; Among them, L1 is the first size; L2 is the fourth size.

5. The bus metal sheet according to claim 1, characterized in that: The N second portions and the first portion form complementary edges of the busbar metal sheet, so that two busbar metal sheets can be spliced ​​to form a regular shape.

6. The bus metal sheet according to claim 5, characterized in that: The regular shape is a rectangle.

7. The bus metal sheet according to claim 5, characterized in that: The first part is a rectangle; the N second parts are rectangles; One length edge of one of the N second portions is flush with one width edge of the first portion to form a continuous edge of the bus metal sheet.

8. The bus metal sheet according to any one of claims 1 to 7, characterized in that: The thickness of the bus metal sheet is greater than or equal to 2 mm.

9. A circuit board, characterized in that: include: A substrate; a confluence point is arranged on the substrate; N power devices; the N power devices are arranged on one surface of the substrate; The busbar metal sheet according to any one of claims 1 to 8; Wherein, N is a positive integer; the bus metal sheet is vertically fixed on the substrate to form a physical connection between each of the power devices and the bus point; the physical connection allows current to pass through.

10. A circuit board, characterized in that: include: substrate; The substrate has a first surface and a second surface which are opposite to each other; a confluence point is arranged on the first surface or the second surface; N first power devices; The first power device is arranged on the first surface of the substrate; N second power devices; the second power devices are arranged on the second surface of the substrate; The busbar metal sheet according to any one of claims 1 to 8; Wherein, N is a positive integer; the second portion of the bus metal sheet passes through the substrate to form a physical connection between the first power device and the second power device; at least a portion of the bus metal sheet also establishes a physical connection with the bus point; and the physical connection allows current to pass through.

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