Switching power supply module structure

Abstract

The invention discloses a switching power supply module structure which comprises a main circuit board, a planar transformer arranged on the main circuit board, a sub-circuit board and a plastic inner frame arranged between the main circuit board and the sub-circuit board, a module structure in which the outer contours of the inner frame, the sub-circuit board and the main circuit board main body are basically overlapped is formed; the sub-circuit board is provided with pins of a golden finger structure, and the pins and the golden finger pins of the main circuit board are combined to form a double-layer golden finger pin structure. Compared with the prior art, the planar transformer is formed by stacking and combining at least two PCBs at intervals in an insulating mode, and compared with a framework transformer, the planar transformer is thin in size, and the product thickness is reduced; and the inner frame is fixedly connected with the main power circuit board and the control circuit board, so that the whole power supply module forms a whole, and the structural strength and the reliability of the whole switching power supply module are improved.

Description

Technical Field

[0001] The present invention relates to the field of AC / DC switching power supplies, and in particular to a high-power, high-power-density, small-volume AC / DC switching power supply module structure. Background Art

[0002] Switching power supply modules can be divided into two categories: AC / DC and DC / DC. DC / DC converters have been modularized, and their design technology and production processes have become mature and standardized both at home and abroad. However, the modularization of AC / DC, due to its own characteristics, encounters more complex technical and process manufacturing problems in the modularization process.

[0003] A specific analysis of the power module (Power Module) as a highly integrated power conversion device has the following core features:

[0004] 1. Basic Definition and Core Characteristics

[0005] Structural features: Using SMT surface mount technology, typical thickness range 3-8mm, support PCB direct welding

[0006] Electrical parameters:

[0007] Input range: AC / DC modules with a wide voltage input range of 85-300V

[0008] Conversion efficiency: Modern products can reach 80-90%

[0009] Thermal management design: thermal balance design enables stable operation in an 85°C environment

[0010] 2. Technology Classification and Evolution Differences

[0011] AC / DC module maturity:

[0012] Topology: Buck / Boost / Buck-Boost / Flyback circuit standardization

[0013] Power density: conventional solution 1.02W / cm 3

[0014] AC / DC technology bottlenecks:

[0015] Volume requirements: Safety distances such as high and low voltage spacing must be met. Conventional single-board structures increase volume by 30%, requiring the integration of high-voltage power devices. In this case, the double-layer structure offers significant advantages over device layout, significantly reducing product volume.

[0016] Safety certification: UL / IEC / EN standard requirements lead to redundant primary and secondary side electrical isolation design

[0017] Process limitations: High-voltage MOSFET placement accuracy requires ±25μm, hindering automation advancement

[0018] 3. Industry Pain Points and Innovation Directions

[0019] Quantitative analysis of existing problems:

[0020] Volume contradiction: The volume of a 30W AC / DC module is 2.5 times that of a DC / DC module of the same level

[0021] As analyzed above, the AC / DC power modules currently on the market are difficult to strike a balance between size, performance, and price. Conventional stacking structures are often connected and fixed with pin header connectors, resulting in low production efficiency. It is difficult to achieve fully automated production in terms of process, and they have poor stability, insufficient strength, and are prone to deformation. Summary of the Invention

[0022] In view of the above problems, the present invention aims to overcome the bottleneck problem of product miniaturization design in the above-mentioned prior art and provide a new switching power supply module structure that can not only achieve all existing electrical performance, but also further improve the power density of the packaging structure and make the product more miniaturized.

[0023] In order to achieve the above object, the present invention provides the following technical solutions:

[0024] A switching power supply module structure includes a main circuit board and a planar transformer arranged thereon. The pins of the main circuit board are gold finger structures. The module also includes a sub-circuit board and a plastic inner frame.

[0025] The inner frame is arranged between the main circuit board and the sub-circuit board, and forms a modular structure in which the outer contours of the inner frame, the sub-circuit board and the main circuit board body substantially coincide with each other;

[0026] The sub-circuit board is provided with pins of a gold finger structure, which are combined with the pins of the gold finger structure of the main circuit board to form a double-layer gold finger pin structure.

[0027] Preferably, the primary and secondary sides of the main circuit board and the sub-circuit board are distributed in the same manner; the double-layer gold finger pins are respectively arranged on both sides to form two groups of gold finger pins with a double-layer structure, which are used as external pins of the primary and secondary sides of the switching power supply respectively, and the two groups of gold finger pins are separated by the safety distance of the primary and secondary sides.

[0028] Preferably, the pins of the gold finger structure of the main circuit board are arranged on both sides, the widths of the pins on both sides are set to be unequal, and the width of the pins on one side is greater than that of the pins on the other side, so as to adapt to different power current transmission occasions.

[0029] Preferably, the pins of the gold finger structure of the main circuit board are arranged on both sides, and the outer contours of the pins on one side of the sub-circuit board and the pins on one side of the main circuit board are substantially coincident.

[0030] Preferably, the double-layer gold finger pin structure is arranged on two sides, with the number of gold finger pins on one side being 3 or 4, and the number of gold finger pins on the other side being 1, 2, 3 or 4.

[0031] Preferably, a large area of ​​copper cladding is provided on the inner layer of the component layout position of the sub-circuit board and / or the main circuit board.

[0032] Preferably, the main body of the inner frame is a rectangular plate-like structure with a hole between the two sides to form a physical isolation that separates the planar transformer core and the secondary side at a safety distance; support plates and / or support bones are erected on both sides of the inner frame, and the support plates extend at both ends in a vertical direction of the board surface; support plates are erected on the outside of the hole of the inner frame to form a retaining wall of the planar transformer; PIN pins are erected on both sides of the inner frame to achieve electrical connection between the main circuit board and the sub-circuit board through the PIN pins.

[0033] Preferably, the supporting bone is a columnar structure and is protruded on the inner side of the support plate along the inner side wall thereof.

[0034] Preferably, the winding layer PCB board of the planar transformer is composed of more than three PCB boards, one of which is formed by the main circuit board, and the remaining winding layer PCB boards are symmetrically distributed on both sides of the main circuit board; the side walls of the winding layer PCB board are formed with side pads by side wall copper plating.

[0035] Preferably, a large through hole is provided on the main circuit board, and a stepped first groove and a second groove are provided on both sides of the large through hole of the main circuit board. The first groove is provided on the inner side of the second groove. The middle column of the magnetic core of the planar transformer is assembled into the large through hole, the side columns of the magnetic core of the planar transformer are assembled into the first groove, and the bracket plate of the inner frame is assembled into the second groove.

[0036] Preferably, an optocoupler is further included, which is arranged on the sub-circuit board and is suitable for the secondary side feedback circuit.

[0037] Preferably, the switching power supply module structure is an open-panel packaging structure, and / or the switching power supply module structure is further sprayed with a conformal coating.

[0038] Compared with the prior art, the switching power supply module structure of the present invention has the following advantages:

[0039] 1. A modular structure that can form a basically gapless combination in which the outer contours of the inner frame, the sub-circuit board, and the main circuit board body substantially overlap can increase the power density of the switching power supply product of the present invention by more than 120% compared with the power density of existing products.

[0040] 2. By adopting new packaging technology and optimizing circuit and structural design, the primary-side feedback circuit is improved to a secondary-side feedback circuit, thereby improving circuit performance and making the miniaturized structure of the switching power supply module structure of the present invention applicable to a power range of 30W to several hundred watts.

[0041] 3. By utilizing the inherent insulation properties of the winding layer PCB board, the primary and secondary sides of this planar transformer with an insulation layer can be electrically isolated up to 5000VAC through the PCB board's own insulation layer. This significantly improves the overall performance of the power supply product, reduces safety distances, reduces volume, and complies with the national standard GB3836.4 for coal mine power supply certification requirements. Compared with traditional transformers, it can better meet market demand.

[0042] 4. By covering the surface of the winding with an insulating film, the insulation safety performance between the winding and the magnetic core can be improved, and various safety certification standards can still be met when the input voltage is high and the output power is large. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A three-dimensional diagram of the switching power supply module structure of the present invention;

[0044] Figure 2 A three-dimensional diagram of the switching power supply module structure of the present invention from another perspective;

[0045] Figure 3 This is a three-dimensional exploded view of the switching power supply module structure of the present invention;

[0046] Figure 4 This is a three-dimensional diagram of the inner frame of the switching power supply module structure of the present invention.

[0047] The descriptions of the accompanying drawings are as follows:

[0048] 100 optocoupler

[0049] 200 main circuit board, 210 pins, 211 primary pins, 212 secondary pins, 214 large through hole, 215 groove, 216 groove

[0050] 300 daughter board, 310 pin, 311 primary pin

[0051] 400 planar transformer, 411.412 magnetic core, 413.414 winding layer PCB board, 415 magnetic core center column, 416 magnetic core side column, 417 side pad

[0052] 500 inner frame, 510 pin, 521 support bone, 522 support plate, 530 hole

[0053] 710 gold finger pin group (primary side pin area), 720 gold finger pin group (secondary side pin area)

[0054] W1.W2. Width of the pins on the main circuit board DETAILED DESCRIPTION

[0055] To meet the increasing market demand for high-power switching power supplies (e.g., above 30W), the performance of the primary-side feedback circuit must be improved, including voltage accuracy, load regulation, and voltage regulation. However, improving the electrical performance of existing primary-side feedback circuits at higher power levels requires high-performance components and a larger product size, significantly limiting the potential for miniaturization of switching power supply packaging. Therefore, further miniaturization requires improvements in circuit principles. Systematic optimization analysis of circuit topologies has identified a preferred secondary-side feedback approach. However, this secondary-side feedback circuit requires an optocoupler for isolation, which, if implemented using a traditional single-circuit board approach, would inevitably increase the product's footprint. Therefore, the inventive concept explores a two-layer structure, placing the optocoupler on a separate circuit board. This minimizes the footprint of the entire power supply assembly on the application circuit board, thereby improving the switching power supply's electrical performance while ensuring increased power density. Of course, with China's mandatory 3C certification for some electronic products, whether an electronic device meets electromagnetic compatibility standards will have a significant impact on its marketability. Therefore, it is crucial to simultaneously consider electromagnetic compatibility improvements while miniaturizing the switching power supply.

[0056] The present invention and its beneficial effects will be further described in detail below with reference to specific implementation methods and the accompanying drawings. However, the specific implementation methods of the present invention are not limited thereto.

[0057] See also Figures 1 to 4 , which is a related figure of the switching power supply of the present invention, a switching power supply module structure, including a main circuit board 200 and a planar transformer 400 arranged thereon, the pins of the main circuit board are gold finger structures,

[0058] It also includes a sub-circuit board 300 and a plastic inner frame 500.

[0059] The inner frame 500 is disposed between the main circuit board 200 and the sub-circuit board 300, and forms a modular structure in which the outer contours of the inner frame, the sub-circuit board, and the main circuit board body substantially coincide with each other;

[0060] The sub-circuit board is provided with pins 310 of a gold finger structure, which are combined with the pins 210 of the gold finger structure of the main circuit board to form a double-layer gold finger pin structure.

[0061] Preferably, Figure 2As shown, the primary and secondary sides of the main circuit board 200 and the sub-circuit board 300 are distributed in the same manner, that is, the primary side of the main circuit board 200 is distributed on the right side and the secondary side is distributed on the left side. The primary and secondary side distribution of the sub-circuit board 300 is also distributed in the same manner, that is, the primary side is distributed on the right side and the secondary side is distributed on the left side. The primary side pins 211 of the main circuit board 200 are led out from the right side, and the secondary side pins 212 are led out from the left side. The sub-circuit board also leads the primary side pins 311 from the right side. If a dual-output product requires additional secondary side pins, they will also be led out from the left side (not shown in the figure). Double-layer gold finger pins are set on both sides, forming two sets of gold finger pins with a double-layer structure. That is, one set of gold finger pins 710 is led out from the primary side, and one set of gold finger pins 720 is led out from the secondary side. They are used as external pins for the primary and secondary sides of the switching power supply, respectively. The two sets of gold finger pins are separated by the safety distance of the primary and secondary sides. Whether the safety distance of the primary and secondary sides is separated can be determined by whether the power supply product meets the relevant requirements of safety certification or whether it has obtained relevant safety certification. Because safety distances vary according to relevant standards and product performance, the use of measurement methods to determine them is limited by the lack of unified measurement standards, and the determination of measured safety distances may lead to different opinions. However, power supply products generally need to meet relevant safety certification requirements, and power supply products that meet safety certifications generally have the separation distance between the primary and secondary sides meet the safety distance requirements, or in other words, the safety distance between the primary and secondary sides is separated. Because the external pins of the primary and secondary sides are located in the same position on the main circuit board and the sub-circuit board and are led out from the primary and secondary sides respectively, only the safety distance on the separate circuit boards needs to be considered, which helps simplify the structural design.

[0062] The widths W1 and W2 of the pins on each side of the main circuit board are set to be unequal on both sides, and the width W2 of the pins on one side is greater than the width W1 of the pins on the other side to adapt to different power current transmission occasions. The unequal width structural design can have a certain anti-mistake assembly effect. The widths of the pins on the same side of the main circuit and the sub-circuit are the same. The outer contours of the pins on one side of the sub-circuit board basically coincide with the outer contours of the pins on one side of the main circuit board, so that the structure of the same group of gold finger pins is consistent, which is convenient for the structural design of the subsequent application circuit board. The basic coincidence of the outer contours of the two, from the measurement perspective, refers to the original values ​​of the same relevant dimensional parameters, and the fluctuation values ​​within the structural tolerance range of the original values ​​of the relevant dimensional parameters; from the projection perspective, it refers to the completely overlapping projection situation, and the overlapping projection situation with local offset within the structural tolerance range.

[0063] The double-layer gold finger pin structure is divided into two sides. In this embodiment, the switching power supply product is a single-output product. The number of gold finger pins on one side is 4 (i.e., the primary side or input side), and the number of gold finger pins on the other side is 2 (i.e., the secondary side or output side). In other implementation scenarios, when designing dual-channel, multi-channel, or single-channel output switching power supply products, the number of gold finger pins on the output side can be increased by coordinating PCB routing, or the number of gold finger pins on both sides can be increased or decreased and adjusted. For example, the number of gold finger pins on one side can be 3 or 4, and the number of gold finger pins on the other side can be 1, 2, 3, or 4. This allows the number of gold finger pins on both sides of the double-layer gold finger pin structure to be flexibly designed to realize the application of the double-layer gold finger pin structure of the switching power supply in different occasions.

[0064] Large areas of copper clad are provided on the inner layers of the main PCB 200 and sub-PCB 300 where components are located. This large area of ​​copper clad can be a single-piece structure, a wound-up winding structure with intermittent winding layers, or a combination of single-piece and intermittent winding structures. This allows for a correspondingly large area of ​​copper clad to overlap on the inner layers of the PCB where multiple components are mounted, fully utilizing the exposed surfaces of the main and sub-PCBs for device heat dissipation.

[0065] like Figure 3 and Figure 4 As shown, the main body of the inner frame 500 is a rectangular plate-like structure with a hole 530 between its two sides, which physically separates the planar transformer core from the secondary side at a safety distance. This allows the planar transformer core on the main circuit board to be inserted during product assembly. Support plates 522 and support ribs 521 are positioned on either side of the inner frame, with the support plates 522 extending perpendicularly from the board surface. The support ribs support the main circuit board and the sub-circuit board, while the support plates are used to limit and clamp the main and sub-circuit boards into pre-positioned positions, eliminating the need for straightening and fixtures during furnace operation. Support plates 522 are positioned outside the hole 530 in the inner frame, forming a retaining wall for the planar transformer. PIN pins are positioned on either side of the inner frame to electrically connect the main circuit board and the sub-circuit board. The support bone 521 is a columnar structure, which is protruded on the inner side of the bracket plate along the inner wall thereof. By stacking the support bone and the bracket plate, the narrow space between the components on the circuit board can be utilized as reasonably as possible. While saving the space within the board, it can also form effective support for the two circuit boards, providing more possibilities for the design of the main components in the miniaturized design of the product.

[0066] The planar transformer's winding layer PCB board is composed of three or more PCB boards 413 and 414, one of which is formed by the main circuit board 200 (414). The remaining winding layer PCB boards 413 are symmetrically distributed on both sides of the main circuit board. Each winding layer PCB board 413 and 414 is provided with an insulating film on its surface to utilize the PCB board's inherent insulation properties to ensure that the switching power supply with an open-panel package structure meets electromagnetic compatibility safety requirements. The side walls of the remaining winding layer PCB boards 413 are formed with side solder pads 417 using copper plating. After the main circuit board 200 and the winding layer PCB boards 413 are welded and fixed via the copper plating side solder pads, a magnetic core is inserted to form a complete high-power density planar transformer. The electrical connection between each winding layer PCB board 413 and the main circuit board 200 is achieved through the soldering connection of the side solder pads. The main circuit board 200 has a large through-hole 214, with stepped grooves 215 and 216 on either side of the large through-hole. Groove 215 is located inside groove 216. The center column 415 of the planar transformer's magnetic core is inserted into the large through-hole 214, and the side columns 416 of the planar transformer's magnetic core are inserted into groove 215. The bracket plate 522 of the inner frame is inserted into groove 216. A planar transformer is composed of at least three or more PCBs stacked in layers with insulation. Compared to a skeleton transformer, a planar transformer is thinner, further reducing product thickness. Multiple outputs can be achieved by flexibly adding windings, coordinating PCB routing, and adding output terminals, meeting the requirements of multiple outputs at high power density.

[0067] Preferably, the switching power supply module structure of the present invention further includes an optocoupler 100, which is arranged on the sub-circuit board 300 and is suitable for use in the secondary side feedback circuit, so that the product's board area does not increase, and can provide an opportunity to improve electrical performance and product power density. The switching power supply module structure of the present invention is an open-plate packaging structure, and a three-proof paint layer is also sprayed on the switching power supply. That is, a coating device is used to coat the PCB board and related protective electronic components in the switching power supply with three-proof paint to protect the PCB circuit board and its related switching power supply products from environmental erosion. Because the three-proof paint has good high and low temperature resistance, it forms a transparent protective film after curing, and has excellent insulation, moisture-proof, anti-leakage, shockproof, dustproof, anti-corrosion, anti-aging, corona resistance and other properties. Therefore, in this embodiment, it is preferred to spray the three-proof paint on the open-plate switching power supply product.

[0068] The switching power supply module structure of the present invention adopts a double-layer structure as a whole, which is divided into a main circuit board and a sub-circuit board. The two boards are connected and supported by an internal frame, which solves the problems of electrical connection and structural strength at the same time. In addition, the layout area of ​​the double-layer PCB is increased, allowing the addition of devices such as optocouplers for secondary-side feedback, solving the problem of poor primary-side feedback performance.

[0069] The switching power supply module structure of the present invention creates a modular structure in which the outer contours of the inner frame, sub-circuit board, and main circuit board body substantially overlap, creating a nearly gapless assembly. An inner frame with pins supports the main and sub-circuit boards and provides electrical connection. The inner frame, main and sub-circuit boards are stacked and fixedly connected, forming a single unit for the entire power supply module, enhancing its structural strength and reliability. This stacked design enables the power supply to achieve high power and compact size. Measurements of existing power supplies with identical electrical performance compared to the switching power supply product of the present invention showed that the power density of the existing product was 1.02W / cm³, while that of the switching power supply product of the present invention was 2.26W / cm³. This indicates that the power density of the switching power supply product of the present invention is over 120% higher than that of existing products.

[0070] In addition, by adopting new packaging technology and system optimization design of optimized circuits, that is, the optimized circuit is improved from a primary-side feedback circuit to a secondary-side feedback circuit, and a new double-layer packaging structure is adopted, the miniaturized structure of the switching power supply module structure of the present invention can be expanded to apply to a power range of 30W to several hundred watts.

[0071] The embodiments of the present invention are not limited thereto. According to the above contents of the present invention, by utilizing common technical knowledge and customary means in the art, without departing from the above basic inventive concept of the present invention, the specific implementation circuits of the present invention may also be modified, replaced or changed in various other forms, all of which fall within the scope of protection of the present invention.

Claims

1. A switching power supply module structure, comprising a main circuit board and a planar transformer mounted thereon, wherein the pins of the main circuit board are gold finger structures, and characterized in that: It also includes a sub-circuit board and a plastic inner frame. The inner frame is arranged between the main circuit board and the sub-circuit board, and forms a modular structure in which the outer contours of the inner frame, the sub-circuit board and the main circuit board body substantially coincide with each other; The sub-circuit board is provided with pins of a gold finger structure, which are combined with the pins of the gold finger structure of the main circuit board to form a double-layer gold finger pin structure.

2. The switching power supply module structure according to claim 1, wherein: The primary and secondary sides of the main circuit board and the sub-circuit board are distributed in the same manner; the double-layer gold finger pins are respectively arranged on both sides to form two groups of gold finger pins with a double-layer structure, which are used as external pins of the primary and secondary sides of the switching power supply respectively, and the two groups of gold finger pins are separated by the safety distance of the primary and secondary sides.

3. The switching power supply module structure according to claim 1, wherein: The pins of the gold finger structure of the main circuit board are arranged on both sides. The widths of the pins on both sides are set to be unequal, and the width of the pins on one side is greater than that of the pins on the other side to adapt to different power current transmission occasions.

4. The switching power supply module structure according to claim 1, wherein: The pins of the gold finger structure of the main circuit board are arranged on both sides, and the outer contours of the pins on one side of the sub-circuit board and the pins on one side of the main circuit board are basically coincident.

5. The switching power supply module structure according to claim 1, wherein: The double-layer gold finger pin structure is arranged on both sides, with the number of gold finger pins on one side being 3 or 4, and the number of gold finger pins on the other side being 1, 2, 3 or 4.

6. The switching power supply module structure according to claim 1, characterized in that: The inner layer of the component layout position of the sub-circuit board and / or the main circuit board is provided with a large area of ​​copper cladding.

7. The switching power supply module structure according to claim 1, characterized in that: The main body of the inner frame is a rectangular plate-like structure with a hole between the two sides to form a safety distance separating the planar transformer core and the secondary side; support plates and / or support bones are erected on both sides of the inner frame, and the support plates extend at both ends in the vertical direction of the board surface; support plates are erected on the outside of the hole of the inner frame to form a retaining wall for the planar transformer; PIN pins are erected on both sides of the inner frame to achieve electrical connection between the main circuit board and the sub-circuit board through the PIN pins.

8. The switching power supply module structure according to claim 7, characterized in that: The support bone is a columnar structure and is convexly arranged on the inner side of the support plate along the inner side wall thereof.

9. The switching power supply module structure according to claim 1, wherein: The winding layer PCB board of the planar transformer is composed of more than three PCB boards, one of which is formed by a main circuit board, and the remaining winding layer PCB boards are symmetrically distributed on both sides of the main circuit board; the side walls of the winding layer PCB board are formed with side solder pads by side wall copper deposition.

10. The switching power supply module structure according to claim 1, wherein: A large through hole is provided on the main circuit board, and a stepped first groove and a second groove are provided on both sides of the large through hole of the main circuit board. The first groove is provided on the inner side of the second groove. The middle column of the magnetic core of the planar transformer is assembled into the large through hole, the side columns of the magnetic core of the planar transformer are assembled into the first groove, and the bracket plate of the inner frame is assembled into the second groove.

11. The switching power supply module structure according to claim 1, wherein: It also includes an optocoupler, which is arranged on the sub-circuit board and is suitable for the secondary side feedback circuit.

12. The switching power supply module structure according to claim 1, wherein: The switching power supply module structure is an open-panel packaging structure, and / or the switching power supply module structure is also sprayed with a conformal coating.

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