A planar transformer

Abstract

This application discloses a planar transformer, comprising: a first circuit board having a first through hole, a first winding portion, and a plurality of first connecting portions, each first connecting portion being electrically connected to the first winding portion; a second circuit board having a second through hole, a second winding portion, and two second connecting portions, each second connecting portion being electrically connected to the second winding portion, the first circuit board and the second circuit board being stacked, and each first connecting portion being electrically connected to the second connecting portion; a magnetic core extending into the first and second through holes to form an electromagnetic induction path, the magnetic core including a first magnetic portion and a second magnetic portion facing each other to clamp the first circuit board and the second circuit board; and a plurality of terminals electrically connected to corresponding first and second connecting portions. This application can reduce the height and board area of ​​the product, which is beneficial for the wiring design of high-current windings, and the product can be modified and functional components can be added by disassembling and replacing one of the circuit boards.

Description

Technical Field

[0001] This application relates to the field of transformer technology, specifically to a planar transformer. Background Technology

[0002] As electronic circuits evolve towards higher frequencies, higher power transmission efficiency, higher power density, higher reliability, higher stability, and higher integration, higher demands are placed on transformer design in power supply circuits. In recent years, planar transformers have begun to replace traditional wire-wound transformers in power supply circuits. Planar transformers are significantly smaller than traditional wire-wound transformers and theoretically offer advantages such as better consistency, easier heat dissipation, lower losses, higher frequencies, lower leakage inductance, and greater stability and reliability, making them ideal for use in flat power supply circuits. However, current planar transformers still face the challenge of simultaneously balancing height and board area, and existing planar transformers are typically pre-assembled products; once the product and circuit design are finalized, it is difficult to modify them according to changes in requirements and usage scenarios. Summary of the Invention

[0003] In view of this, this application provides a planar transformer that can improve the problems of existing planar transformers that are difficult to simultaneously achieve small height and small board area, as well as the problem of difficulty in making product changes.

[0004] This application provides a planar transformer, comprising:

[0005] At least one first circuit board, the first circuit board having a first through hole, a first winding portion and a plurality of first connecting portions, each of the first connecting portions being electrically connected to the first winding portion;

[0006] A second circuit board is provided with a second through hole, a second winding portion and two second connecting portions. Each of the second connecting portions is electrically connected to the second winding portion. The first circuit board and the second circuit board are stacked, and the first connecting portion and the second connecting portion are electrically connected in a one-to-one correspondence, so as to electrically connect the first winding portion and the second winding portion to form a winding of the planar voltage transformer.

[0007] A magnetic core extends into the corresponding first and second through holes and forms an electromagnetic induction path with the first winding portion and the second winding portion. The magnetic core includes a first magnetic portion and a second magnetic portion that are attached to each other. The first magnetic portion and the second magnetic portion clamp the first circuit board and the second circuit board.

[0008] Several terminals, each terminal being electrically connected to a corresponding first connection part and a second connection part.

[0009] Optionally, the first winding section and the second winding section are electrically connected as the primary winding or secondary winding of the planar transformer.

[0010] Optionally, the first through-hole is a single cutout area formed on the first circuit board;

[0011] The second through hole includes three hollow areas arranged at intervals in sequence;

[0012] The magnetic core includes a magnetic center column and two magnetic walls spaced apart on both sides of the magnetic center column. The magnetic center column extends to a hollow area in the middle of the first through hole and the second through hole. The first winding portion is arranged around the first through hole, and the second winding portion is arranged around a hollow area in the middle of the second through hole. The two magnetic walls extend to the other two hollow areas of the second through hole.

[0013] The first circuit board and the first winding section are both located between the two magnetic walls.

[0014] Optionally, the first through hole includes three hollow areas arranged at intervals in sequence;

[0015] The second through hole includes three hollow areas arranged at intervals in sequence;

[0016] The magnetic core includes a magnetic center column and two magnetic walls spaced apart on both sides of the magnetic center column. The magnetic center column extends to a central hollow area of ​​the first through hole and a central hollow area of ​​the second through hole. The first winding portion is arranged around the central hollow area of ​​the first through hole, and the second winding portion is arranged around the central hollow area of ​​the second through hole. The two magnetic walls extend to the other two hollow areas of the first through hole and the other two hollow areas of the second through hole.

[0017] Optionally, the three cutout areas of the first through hole are aligned vertically with the three cutout areas of the second through hole.

[0018] Optionally, the first connecting portion and the second connecting portion are aligned one by one along the stacking direction of the first circuit board and the second circuit board.

[0019] Optionally, the first connecting portion includes a first via penetrating the first circuit board and a conductive layer at least disposed on the inner wall of the first via; the second connecting portion includes a second via penetrating the second circuit board and a conductive layer at least disposed on the inner wall of the second via; the terminal is inserted into the aligned first and second vias and contacts the conductive layer in the corresponding via.

[0020] Optionally, the conductive layer includes solder paste.

[0021] Optionally, the first connecting part and the second connecting part are electrically connected by wiring, and the terminal is in direct contact with one of the first connecting part and the second connecting part to achieve electrical connection.

[0022] Optionally, the first circuit board may also be provided with copper sheets or current transformers.

[0023] As described above, this application sets one winding of the planar voltage transformer on two circuit boards respectively. The two circuit boards are electrically connected through the first connection part and the second connection part. Finally, the magnetic core is assembled to realize the integration of the product. This can not only effectively reduce the height of the product and the board area, but also facilitate better wiring design of the high current winding. Moreover, the product can be changed by disassembling and replacing one of the circuit boards.

[0024] In addition, this application can also enable other functions for the planar transformer by adding functional devices on one of the circuit boards, such as assembling copper sheets to improve the current carrying capacity and heat dissipation of the entire circuit, or adding current transformers to enable related testing and protection of the circuit. Attached Figure Description

[0025] Figure 1 This is an exploded view of the structure of a planar transformer according to an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the structure of the magnetic component according to an embodiment of this application;

[0027] Figure 3 This is a partial exploded view of a planar transformer according to another embodiment of this application.

[0028] First direction x, second direction y, third direction z;

[0029] Planar transformer 100, first circuit board 1, second circuit board 2, magnetic core 3, terminal 4;

[0030] First through hole 10, first connecting part 12;

[0031] Second through hole 20, second connecting part 22;

[0032] First through hole 120, second through hole 220, hollow area 201, hollow area 202, hollow area 203, first magnetic section 31, second magnetic section 32, magnetic central column 33, magnetic wall 34. Detailed Implementation

[0033] To address the aforementioned problems in the prior art, this application provides a solution. These protected subjects are based on the same concept, and the principles for solving the problems are basically the same or similar. The implementation methods of each protected subject can be referred to mutually, and repeated details will not be elaborated.

[0034] In the various examples provided in this application, a winding of a planar voltage transformer is respectively disposed on two circuit boards. The two circuit boards are electrically connected through a first connection part and a second connection part. Finally, the magnetic core is assembled to achieve product integration, thereby reducing the product height and board area, and enabling product changes by disassembling and replacing one of the circuit boards.

[0035] The specific form of the shape, quantity, size, and other parameters of any of the components such as the planar voltage transformer, each winding section, terminal, magnetic core, first connection section, and second connection section can be determined according to the adaptability required by the actual scenario, and this application does not limit it.

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly described below in conjunction with specific embodiments and corresponding drawings. Obviously, the embodiments described below are only a part of the embodiments of this application, and not all of them. Unless otherwise specified, the following embodiments and their technical features can be combined with each other, and also belong to the technical solutions of this application.

[0037] Please refer to the following: Figure 1 and Figure 2 As shown, the planar transformer 100 of this example includes: at least one first circuit board 1, a second circuit board 2, a magnetic core 3, and a plurality of terminals 4. The number of the first circuit board 1 and the number of terminals 4 can be adapted to the type of the planar transformer 100. For example, the planar transformer 100 shown in the figure may be provided with one first circuit board 1 and four terminals 4.

[0038] For ease of description and understanding, and considering the placement shown in the figure, the width direction of the planar voltage transformer 100 is referred to as the first direction x, the height direction as the second direction y, and the thickness direction as the third direction z. The first direction x, the second direction y, and the third direction z are all perpendicular to each other and can be considered as the three coordinate axes of a three-dimensional rectangular coordinate system. It should be understood that the term "perpendicular" throughout this application does not require the angle between the two directions to be exactly 90°, but rather allows for deviations such as ±10°. That is, "perpendicular" can be understood as the angle between any two directions being between 80° and 100°. Similarly, the term "parallel" throughout this application does not require the angle between the two directions to be exactly 0° or 180°, but rather allows for deviations such as ±10°. That is, "parallel" can be understood as the angle between any two directions being between 0° and 10° or between 170° and 190°.

[0039] The first circuit board 1 is provided with a first through hole 10, a first winding portion (not shown in the figure) and a plurality of first connecting portions 12. Each first connecting portion 12 is electrically connected to the first winding portion, that is, each first connecting portion 12 can be regarded as an external terminal or external portion of the first winding portion.

[0040] exist Figures 1 to 2 In the example, the first through-hole 10 is a single cutout area formed on the first circuit board 1, and can be circular. The first winding portion is disposed around the circular first through-hole 10. In practical scenarios, the first winding portion can be formed on the first circuit board 1 using a printing process. For example, the first circuit board 1 includes, but is not limited to, a PCB (Printed Circuit Board) type circuit board, which has multiple layers of traces (i.e., copper plating) inside. Adjacent layers of traces are insulated by insulating material, and different layers of traces are coupled through vias and conductive posts disposed in the vias, that is, so-called interlayer coupling is achieved. Based on this, the first winding portion can include traces or conductive patterns disposed on multiple layers, and are formed by sequential electrical connections through corresponding vias. Its specific form can be determined according to the adaptability of the planar transformer 100 and the trace design of the first circuit board 1.

[0041] The second circuit board 2 is provided with a second through hole 20, a second winding section (not shown in the figure) and two second connecting sections 22. Each second connecting section 22 is electrically connected to the second winding section, that is, each second connecting section 22 can be regarded as an external terminal or external section of the second winding section.

[0042] The first circuit board 1 and the second circuit board 2 are stacked along the second direction y. Figure 1 In the example, the area of ​​the first circuit board 1 is smaller than the area of ​​the second circuit board 2. Here, the first circuit board 1 can be called the secondary circuit board 1, the second circuit board 2 can be called the main circuit board 2, and the first circuit board 1 can be stacked on the second circuit board 2.

[0043] exist Figure 1 In the example, the second through hole 20 includes three cutout areas 201, 202, and 203 formed on the second circuit board 2. These three cutout areas 201, 202, and 203 are arranged alternately along the first direction x. Throughout this application, "alternate arrangement" refers to a minimum distance of non-zero between two entities, meaning they do not contact each other. The middle cutout area 202 can be circular. The second winding portion is arranged around the circular middle cutout area 202. In practical scenarios, similar to the aforementioned first winding portion, the second winding portion can be formed on the first circuit board 1 using a printing process. For example, the second circuit board 2 includes, but is not limited to, a PCB or similar type of circuit board, which has multiple layers of traces. Adjacent layers of traces are insulated by insulating material, and different layers of traces are coupled through vias and conductive posts disposed in the vias, i.e., achieving so-called interlayer coupling. Based on this, the second winding portion may include traces or conductive patterns disposed on multiple layers, and be formed by sequential electrical connections through corresponding vias. Its specific form can be determined according to the adaptability of the trace design of the planar transformer 100 and the second circuit board 2.

[0044] With the first circuit board 1 and the second circuit board 2 stacked, the first connecting portion 12 and the second connecting portion 22 are electrically connected in a one-to-one correspondence to electrically connect the first winding portion and the second winding portion, thereby forming a winding of the planar transformer 100. In one example, the first winding portion and the second winding portion are electrically connected as the primary winding or secondary winding of the planar transformer 100.

[0045] The magnetic core 3 extends into the corresponding first through hole 10 and second through hole 20, forming an electromagnetic induction path with the first winding portion and the second winding portion. Figure 1 In the example, the magnetic core 3 includes a first magnetic portion 31 and a second magnetic portion 32. These two magnetic portions can be arranged symmetrically along the xz plane, and the first magnetic portion 31 and the second magnetic portion 32 are bonded together in opposite directions along the second direction y to form the magnetic core 3, for example, by adhesive bonding, thereby forming a magnetic core 3 with a complete closed magnetic path. The magnetic core 3 includes a magnetic center post 33 and two magnetic walls 34 spaced apart on both sides of the magnetic center post 33 along the first direction x. The magnetic center post 33 extends into a single hollow area of ​​the first through hole 10 and into a middle hollow area 202 of the second through hole 20. The two magnetic walls 34 extend into the other two hollow areas 201 and 203 of the second through hole 20. Along the first direction x, the first circuit board 1 and the first winding portion are both located between the two magnetic walls 34. The first magnetic portion 31 and the second magnetic portion 32 clamp the first circuit board 1 and the second circuit board 2 along the second direction y, thereby forming an electromagnetic induction path between the magnetic core 3 and the first winding portion and the second winding portion.

[0046] Each terminal 4 is electrically connected to the corresponding first connecting part 12 and second connecting part 12. For example, in Figure 1 In the example shown, the planar transformer 100 has four terminals 4, two of which are located on one side of the planar transformer 100, and the other two are located on the other side. These two sides are positioned opposite each other along a third direction z, and the two terminals 4 on each side are spaced apart along a first direction x. The four terminals 4 can have the same shape or different shapes. For ease of description, this application and all accompanying drawings use the example of four terminals 4 having the same shape for description and illustration.

[0047] As described above, this application sets one winding of the planar voltage transformer 100 on two circuit boards, a first circuit board 1 and a second circuit board 2. The two circuit boards are electrically connected through a first connecting part 12 and a second connecting part 22. Finally, the magnetic core 3 is assembled to achieve product integration. This not only effectively reduces the product height and board area, which is beneficial for better wiring design of high-current windings, but also allows for product changes by disassembling and replacing one of the circuit boards. For example, in the scenario where the first circuit board 1 is a secondary circuit board 1 and the second circuit board 2 is a primary circuit board 2, the first circuit board 1 can be disassembled and replaced without any changes to the second circuit board 2 and its second winding portion. This allows the first winding portion on the replaced first circuit board 1 to form a winding with other properties with the second winding portion on the second circuit board 2, thereby changing the product performance of the entire planar voltage transformer 100 after replacement compared to before replacement.

[0048] In addition, the magnetic core 3 is assembled and bonded, so even if one of the first magnetic part 31 and the second magnetic part 32 cracks or breaks, it can be replaced relatively easily.

[0049] In the planar voltage transformer 100 of this application, the electrical connection method between the first connecting part 12 and the second connecting part 22 can be determined according to actual needs and is not limited in this application.

[0050] For example, in Figure 1 In the example described, along the stacking direction of the first circuit board 1 and the second circuit board 2, the first connecting portion 12 and the second connecting portion 22 can be vertically aligned and electrically connected using a plug-in or soldering method. Specifically, the first connecting portion 12 includes a first via 120 penetrating the first circuit board 1 and a conductive layer (not shown) at least disposed on the inner wall of the first via 120. The second connecting portion 22 includes a second via 220 penetrating the second circuit board 2 and a conductive layer (not shown) at least disposed on the inner wall of the second via 220. When the first connecting portion 12 and the second connecting portion 22 are vertically aligned, electrical connection can be achieved through the conductive layer. Optionally, the conductive layer includes solder paste.

[0051] In one example, the terminal 4 is inserted into aligned first vias 120 and second vias 220, and contacts the conductive layer within the corresponding vias. Here, the terminal 4 is electrically connected to the corresponding first connecting portion 12 and second connecting portion 22. This method also reduces the risk of terminal 4 breakage due to vibration or other reasons, ensuring the stability of the terminal 4 assembly.

[0052] In another example, the first connecting portion 12 and the second connecting portion 22 can be electrically connected by wiring. For example, the first connecting portion 12 and the second connecting portion 22 can be respectively represented as pads, and the two pads are electrically connected by wiring; the terminal 4 directly contacts one of the first connecting portion 12 and the second connecting portion 22 to achieve electrical connection.

[0053] exist Figure 1 In the example shown, the first through-hole 10 is a single cutout area formed on the first circuit board 1, and the size of the first circuit board 1 is relatively small. In other examples, the first circuit board 1 can be implemented as a larger circuit board. For example, the first through-hole 10 also includes three cutout areas (not shown) arranged sequentially at intervals along the first direction x, and the second through-hole 20 also includes three cutout areas arranged sequentially at intervals along the first direction x. Figure 1 The three cutout areas 201, 202, and 203 shown are shown. Optionally, the three cutout areas of the first through hole 10 have the same shape as the three cutout areas 201, 202, and 203 of the second through hole 20, and are aligned vertically.

[0054] The magnetic core 3 includes a magnetic center post 33 and two magnetic walls 34 spaced apart on both sides of the magnetic center post 33 along a first direction x. The magnetic center post 33 extends into a central hollow area of ​​the first through hole 10 and a central hollow area 202 of the second through hole 20. The first winding portion is arranged around the central hollow area of ​​the first through hole 10, and the second winding portion is arranged around the central hollow area 202 of the second through hole 20. The two magnetic walls 34 extend into two other hollow areas of the first through hole 10 and two other hollow areas 201 and 203 of the second through hole 20. Along the first direction x, the first circuit board 1 and the first winding portion are both located between the two magnetic walls 34. The first magnetic portion 31 and the second magnetic portion 32 clamp the first circuit board 1 and the second circuit board 2 along a second direction y. Here, the magnetic core 3 and the first winding portion and the second winding portion form an electromagnetic induction path. At this time, the first circuit board 1 also extends beyond the two magnetic walls 34 along the first direction x, so the size of the first circuit board 1 is larger, and a larger board area can be achieved.

[0055] For example, in addition to the first winding section, other functional devices, including but not limited to copper sheets or current transformers, can also be provided on the first circuit board 1. Similarly, other functional devices can also be provided on the second circuit board 2. That is to say, this application can achieve other corresponding functions for the planar transformer 100 by adding functional devices to one of the circuit boards. For example, copper sheets can be assembled to improve the current carrying capacity and heat dissipation of the entire circuit, or a current transformer can be added to achieve relevant testing and protection of the planar transformer 100 circuit.

[0056] The planar voltage transformer 100 of this application embodiment can also inherit multiple windings. Please refer to [link to relevant documentation]. Figure 3 As shown, the planar voltage converter 100 may include multiple such... Figure 1 The first circuit board 1 shown in the figure is only illustrated with three first circuit boards 1 for illustrative purposes. The assembly method of each first circuit board 1 and the second circuit board 2 can be referred to the foregoing and will not be repeated here. The magnetic core 3 of the planar voltage transformer 100 may contain only two magnetic parts, which is equivalent to the aforementioned Figure 1 The multiple first magnetic parts 31 shown are implemented as a single magnetic part, and the multiple second magnetic parts 32 are implemented as another single magnetic part. After the assembly of each first circuit board 1 and second circuit board 2 is completed, the two magnetic parts can be directly aligned and attached.

[0057] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. For those skilled in the art, any equivalent structural transformations made using the content of this specification and drawings are similarly included within the patent protection scope of this application.

[0058] In the description of the embodiments of this application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solutions of the corresponding embodiments, and are not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limitations on this application.

[0059] Although this document uses terms such as "first," "second," etc., to describe various types of information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. Furthermore, the singular forms "a," "an," and "the" are intended to also include the plural forms. The terms "or" and "and / or" are interpreted as inclusive, or meaning either one or any combination thereof. Exceptions to this definition only arise when combinations of elements, functions, steps, or operations are inherently mutually exclusive in some way.

Claims

1. A planar transformer, characterized by The planar transformer comprises: at least one first circuit board provided with a first through hole, a first winding part and a plurality of first connecting parts, each of the first connecting parts being electrically connected with the first winding part; a second circuit board provided with a second through hole, a second winding part and two second connecting parts, each of the second connecting parts being electrically connected with the second winding part, the first circuit board and the second circuit board being stacked, and the first connecting parts and the second connecting parts being aligned and electrically connected one by one to electrically connect the first winding part and the second winding part as a winding of the planar transformer; the first connecting part comprises a first via hole penetrating the first circuit board and a conductive layer provided at least on the inner wall of the first via hole, and the second connecting part comprises a second via hole penetrating the second circuit board and a conductive layer provided at least on the inner wall of the second via hole; a magnetic core extending into the corresponding first through hole and second through hole and forming an electromagnetic induction path with the first winding part and the second winding part, the magnetic core comprising a first magnetic part and a second magnetic part facing each other, the first magnetic part and the second magnetic part clamping the first circuit board and the second circuit board; a plurality of terminals, each of the terminals being electrically connected with the corresponding first connecting part and second connecting part, each of the terminals being inserted into the aligned first via hole and second via hole and being in contact with the conductive layer in the corresponding via hole.

2. The planar transformer according to claim 1, characterized in that The first winding part and the second winding part are electrically connected as a primary winding or a secondary winding of the planar transformer.

3. The planar transformer according to claim 1 or 2, wherein the first through hole is a single hollow area formed in the first circuit board; the second through hole comprises three hollow areas arranged in sequence; the magnetic core comprises a magnetic column and two magnetic walls arranged on both sides of the magnetic column, the magnetic column extending to the middle hollow area of the first through hole and the middle hollow area of the second through hole, the first winding part being arranged around the first through hole, the second winding part being arranged around the middle hollow area of the second through hole, and the two magnetic walls extending to the other two hollow areas of the second through hole; the first circuit board and the first winding part are located between the two magnetic walls.

4. The planar transformer according to claim 1 or 2, wherein the first through hole comprises three hollow areas arranged in sequence; the second through hole comprises three hollow areas arranged in sequence; the magnetic core comprises a magnetic column and two magnetic walls arranged on both sides of the magnetic column, the magnetic column extending to the middle hollow area of the first through hole and the middle hollow area of the second through hole, the first winding part being arranged around the middle hollow area of the first through hole, the second winding part being arranged around the middle hollow area of the second through hole, and the two magnetic walls extending to the other two hollow areas of the first through hole and the other two hollow areas of the second through hole.

5. The planar transformer according to claim 4, characterized in that The three hollow areas of the first through hole and the three hollow areas of the second through hole are aligned vertically.

6. The planar transformer of claim 1, wherein, The conductive layer comprises tin paste.

7. The planar transformer of claim 1, wherein, The first connecting part and the second connecting part are electrically connected through a wire, and the terminal is directly in contact with one of the first connecting part and the second connecting part to realize electrical connection.

8. The planar transformer of claim 1, wherein, The first circuit board is further provided with a copper sheet or a current transformer.

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