Planar transformer

Abstract

The planar transformer comprises a first circuit board which is provided with a first through hole, a first winding part and a plurality of first connecting parts, and each first connecting part is electrically connected with the first winding part; the second circuit board is provided with a second through hole, a second winding part and two second connecting parts, each second connecting part is electrically connected with the second winding part, the first circuit board and the second circuit board are stacked, and the first connecting parts and the second connecting parts are electrically connected one by one; the magnetic core extends into the first through hole and the second through hole to form an electromagnetic induction path, and the magnetic core comprises a first magnetic branch part and a second magnetic branch part which are oppositely attached to each other so as to clamp the first circuit board and the second circuit board; and the plurality of terminals are electrically connected with the corresponding first connecting parts and the second connecting parts. According to the invention, the height and the layout area of the product can be reduced, the wiring design of the large-current winding is facilitated, and the product can be changed and functional devices can be additionally arranged by detaching and replacing one circuit board.

Description

Technical Field

[0001] The present application relates to the technical field of transformers, and in particular to a planar transformer. Background Art

[0002] As electronic circuits develop towards high frequency, high power transmission efficiency, high power density, high reliability, high stability, and high integration, higher requirements are placed on the design of transformers in power circuits. In recent years, planar transformers have begun to be used to replace traditional wire-wound transformers in power circuits. The volume of planar transformers is much smaller than that of traditional wire-wound transformers. In theory, they also have the characteristics of good consistency, easy heat dissipation, low loss, high frequency, small leakage inductance, stability and reliability. Therefore, they are very suitable for use in flat power circuits. However, the current planar transformers still have the problem of difficulty in taking into account both height and board area at the same time, and the existing planar transformers are usually pre-installed products. Once the product and circuit solution are formed, it is difficult to change according to changes in demand and usage scenarios. Summary of the invention

[0003] In view of this, the present application provides a planar transformer, which can improve the problem that the existing planar transformer is difficult to achieve both a small height and a small board area, and the problem that it is difficult to make product changes.

[0004] The present application provides a planar transformer, comprising:

[0005] At least one first circuit board, wherein the first circuit board is provided with 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, provided with a second through hole, a second winding portion and two second connecting portions, each of the second connecting portions being electrically connected to the second winding portion, the first circuit board and the second circuit board being stacked, and the first connecting portion being electrically connected to the second connecting portion 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 transformer;

[0007] a magnetic core extending into the corresponding first through hole and the second through hole and forming an electromagnetic induction path with the first winding portion and the second winding portion, the magnetic core comprising a first magnetic portion and a second magnetic portion facing each other, the first magnetic portion and the second magnetic portion clamping the first circuit board and the second circuit board;

[0008] A plurality of terminals, each terminal being electrically connected to the corresponding first connecting portion and the second connecting portion.

[0009] Optionally, the first winding portion and the second winding portion are electrically connected to form a primary winding or a secondary winding of the planar transformer.

[0010] Optionally, the first through hole is a single hollow area formed in the first circuit board;

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

[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 between the first through hole and the second through hole, the first winding portion is arranged around the first through hole, the second winding portion is arranged around a hollow area in the middle of the second through hole, and 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 portion are both located between the two magnetic walls.

[0014] Optionally, the first through hole includes three hollow areas that are sequentially spaced apart;

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

[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 middle hollow area of ​​the first through hole and a middle hollow area of ​​the second through hole, the first winding portion is arranged around a middle hollow area of ​​the first through hole, the second winding portion is arranged around a middle hollow area of ​​the second through hole, and 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 hollow areas of the first through hole are aligned vertically with the three hollow areas of the second through hole.

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

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

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

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

[0022] Optionally, a copper sheet or a current transformer is also provided on the first circuit board.

[0023] As described above, the present application arranges a winding of a planar voltage transformer on two circuit boards respectively. The two circuit boards are electrically connected through a first connecting part and a second connecting part, and finally the magnetic core is assembled to realize product integration. This can not only effectively reduce the height and board area of ​​the product, which is conducive to better wiring design of large current windings, but also the product can be changed by disassembling and replacing one of the circuit boards.

[0024] In addition, the present application can also realize 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 flow and heat dissipation of the entire circuit, or adding current transformers to realize relevant testing and protection of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of an exploded structure of a planar transformer according to an embodiment of the present application;

[0026] Figure 2 is a schematic structural diagram of a magnetic sub-unit according to an embodiment of the present application;

[0027] Figure 3 It is a schematic diagram of a partial structure explosion of a planar transformer according to another embodiment of the present application.

[0028] A first direction x, a second direction y, and a third direction z;

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

[0030] A first through hole 10 and a first connecting portion 12;

[0031] A second through hole 20 and a second connecting portion 22;

[0032] The first via hole 120 , the second via hole 220 , the hollow area 201 , the hollow area 202 , the hollow area 203 , the first magnetic division 31 , the second magnetic division 32 , the magnetic center column 33 , and the magnetic wall 34 . DETAILED DESCRIPTION

[0033] In order to solve the above problems existing in the prior art, the present application provides a method. These several protection themes are based on the same concept, and the principles of solving the problems are basically the same or similar. The implementation methods of each protection theme can refer to each other, and the repeated parts will not be repeated.

[0034] In each example provided in the present application, a winding of a planar voltage transformer is respectively arranged on two circuit boards, and the two circuit boards are electrically connected through a first connecting part and a second connecting part. Finally, the magnetic core is assembled to realize product integration, thereby reducing the height and layout area of ​​the product, and realizing product changes by disassembling and replacing one of the circuit boards.

[0035] The specific expression of parameters such as shape, quantity, size, etc. of any of the planar transformer, each winding part, terminal, magnetic core, first connecting part, second connecting part, etc. can be determined according to the adaptability required by the actual scenario, and this application is not limited.

[0036] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly described below in conjunction with specific embodiments and corresponding drawings. Obviously, the embodiments described below are only part of the embodiments of the present application, not all of the embodiments. In the absence of conflict, the following embodiments and their technical features can be combined with each other and also belong to the technical solutions of the present application.

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

[0038] For ease of description and understanding, in combination with the placement orientation shown in the figure, the width direction of the planar voltage device 100 is called the first direction x, the height direction is called the second direction y, and the thickness direction is called the third direction z. The first direction x, the second direction y and the third direction z are perpendicular to each other and can be regarded as the three coordinate axes of the three-dimensional rectangular coordinate system. It should be understood that the so-called verticality in the whole application does not require that the angle between the two must be 90°, but allows a deviation of, for example, ±10°, that is, the so-called verticality can be understood as the angle between any two directions is 80° to 100°. Similarly, the so-called parallelism in the whole application does not require that the angle between the two must be 0° or 180°, but allows a deviation of, for example, ±10°, that is, the so-called parallelism can be understood as the angle between any two directions is 0° to 10° or 170° to 190°.

[0039] The first circuit board 1 is provided with a first through hole 10, a first winding portion (not shown) 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 Figure 1 to Figure 2 In the example, the first through hole 10 is a single hollow area formed on the first circuit board 1, which can be circular. The first winding portion is arranged around the first circular through hole 10. In actual scenarios, the first winding portion can be formed on the first circuit board 1 by a printing process. For example, the first circuit board 1 includes but is not limited to a circuit board of the type of PCB (Printed Circuit Board), which has multiple layers of wiring (i.e., copper cladding) inside, and the adjacent two layers of wiring are insulated by insulating materials. The wiring of different layers is coupled through vias and conductive columns arranged in the vias, that is, the so-called interlayer coupling is realized. Based on this, the first winding portion may include wiring or conductive patterns arranged in multiple layers, and is formed by sequential electrical connection through corresponding vias. Its specific form of expression can be determined according to the adaptability of the wiring design of the planar transformer 100 and the first circuit board 1.

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

[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 a secondary circuit board 1, the second circuit board 2 can be called a 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 hollow areas 201, 202, 203 formed on the second circuit board 2, and the three hollow areas 201, 202, 203 are arranged in sequence along the first direction x. The so-called interval arrangement in the whole application refers to the minimum distance between the two main bodies that is not equal to zero, that is, the two are not in contact. The hollow area 202 located in the middle can be circular. The second winding part is arranged around the circular middle hollow area 202. In the actual scene, similar to the aforementioned first winding part, the second winding part can be formed on the first circuit board 1 by a printing process. For example, the second circuit board 2 includes but is not limited to a circuit board of the type of PCB, which has multiple layers of wiring inside, and the adjacent two layers of wiring are insulated by insulating materials. The wiring of different layers is coupled through vias and conductive columns arranged in the vias, that is, the so-called interlayer coupling is realized. Based on this, the second winding portion may include routing or conductive patterns arranged in multiple layers and electrically connected in sequence through corresponding vias. Its specific form may be determined according to the routing design adaptability of the planar transformer 100 and the second circuit board 2.

[0044] When the first circuit board 1 and the second circuit board 2 are stacked, the first connection portion 12 and the second connection portion 22 are electrically connected one by one to electrically connect the first winding portion and the second winding portion, so that the first winding portion and the second winding portion form a winding of the planar transformer 100. In an example, the first winding portion and the second winding portion are electrically connected to form a primary winding or a 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, and forms an electromagnetic induction path with the first winding part and the second winding part. Figure 1 In the example, the magnetic core 3 includes a first magnetic section 31 and a second magnetic section 32, and the two magnetic sections can be arranged completely symmetrically along the xz plane, and the first magnetic section 31 and the second magnetic section 32 are attached to each other along the second direction y to form the magnetic core 3, for example, by gluing, so as to form a magnetic core 3 with a complete closed magnetic path. The magnetic core 3 includes a magnetic center column 33 and two magnetic walls 34 arranged at intervals on both sides of the magnetic center column 33 along the first direction x, the magnetic center column 33 extends to a single hollow area of ​​the first through hole 10 and a hollow area 202 in the middle of the second through hole 20, and the two magnetic walls 34 extend to 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 part are both located between the two magnetic walls 34; the first magnetic section 31 and the second magnetic section 32 clamp the first circuit board 1 and the second circuit board 2 along the second direction y, whereby the magnetic core 3 and the first winding part and the second winding part form an electromagnetic induction path.

[0046] Each terminal 4 is electrically connected to the corresponding first connection portion 12 and the second connection portion 12. Figure 1 In the example shown, the planar transformer 100 is provided with four terminals 4, two of which are provided on one side of the planar transformer 100, and the other two terminals 4 are provided on the other side of the planar transformer 100, the two sides are arranged relative to each other along the third direction z, and the two terminals 4 on each side are arranged at intervals along the first direction x. The shapes of the four terminals 4 can be the same or different. For ease of description, the entire text of this application and all drawings are described and shown as an example in which the shapes of the four terminals 4 are the same.

[0047] As described above, the present application arranges a winding of the planar voltage generator 100 on the first circuit board 1 and the second circuit board 2 respectively. The two circuit boards are electrically connected through the first connecting portion 12 and the second connecting portion 22, and finally the magnetic core 3 is assembled to realize product integration. This can not only effectively reduce the height and board area of ​​the product, but also facilitate better wiring design of large current windings, and the product can be changed by disassembling and replacing one of the circuit boards. For example, in a scenario where the first circuit board 1 is the auxiliary circuit board 1 and the second circuit board 2 is the main circuit board 2, the first circuit board 1 can be disassembled and replaced without making any changes to the second circuit board 2 and the second winding portion thereon, that is, the first winding portion on the replaced first circuit board 1 can be formed into a winding with other performance with the second winding portion on the second circuit board 2, so that the product performance of the entire planar voltage generator 100 after replacement is changed compared to before replacement.

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

[0049] In the planar transformer 100 of the present application, the electrical connection method between the first connection part 12 and the second connection part 22 can be determined according to actual needs and is not limited in the present 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 connection part 12 and the second connection part 22 can be aligned one by one up and down, and the electrical connection is achieved by plugging or welding. Specifically, the first connection part 12 includes a first via hole 120 penetrating the first circuit board 1 and a conductive layer (not shown) at least arranged on the inner wall of the first via hole 120, and the second connection part 22 includes a second via hole 220 penetrating the second circuit board 2 and a conductive layer (not shown) at least arranged on the inner wall of the second via hole 220. When the first connection part 12 and the second connection part 22 are aligned one by one up and down, the 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 the aligned first via hole 120 and the second via hole 220, and contacts the conductive layer in the corresponding via hole, whereby the terminal 4 is electrically connected to the corresponding first connection portion 12 and the second connection portion 22. This method can also reduce the risk of terminal 4 breaking and failing due to vibration and other reasons, and ensure the stability of terminal 4 assembly.

[0052] In another example, the first connection portion 12 and the second connection portion 22 can be electrically connected via routing. For example, the first connection portion 12 and the second connection portion 22 can be respectively expressed as pads, and the two pads are electrically connected via routing; the terminal 4 is in direct contact with one of the first connection portion 12 and the second connection portion 22 to achieve electrical connection.

[0053] exist Figure 1 In the example shown, the first through hole 10 is a single hollow area formed in 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 hollow areas (not shown) sequentially arranged along the first direction x, and the second through hole 20 also includes three hollow areas sequentially arranged along the first direction x, that is, Figure 1 The three hollow areas 201, 202, 203 are shown in FIG. Optionally, the three hollow areas of the first through hole 10 and the three hollow areas 201, 202, 203 of the second through hole 20 have the same shape and are aligned one by one.

[0054] The magnetic core 3 includes a magnetic center column 33 and two magnetic walls 34 arranged at intervals on both sides of the magnetic center column 33 along the first direction x, the magnetic center column 33 extends to the middle hollow area of ​​the first through hole 10 and the middle hollow area 202 of the second through hole 20, the first winding part is arranged around the middle hollow area of ​​the first through hole 10, and the second winding part is arranged around the middle hollow area 202 of the second through hole 20, and the two magnetic walls 34 extend to the other two hollow areas of the first through hole 10 and the other two hollow areas 201, 203 of the second through hole 20; along the first direction x, the first circuit board 1 and the first winding part are both located between the two magnetic walls 34; the first magnetic division 31 and the second magnetic division 32 clamp the first circuit board 1 and the second circuit board 2 along the second direction y, whereby the magnetic core 3 and the first winding part and the second winding part 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 large, and a large layout area can be achieved.

[0055] For example, in addition to the first winding portion, other functional devices may be provided on the first circuit board 1, including but not limited to copper sheets or current transformers. Similarly, other functional devices may also be provided on the second circuit board 2. In other words, the present application may realize other corresponding functions for the planar transformer 100 by adding functional devices to one of the circuit boards, such as assembling copper sheets to improve the current flow and heat dissipation effect of the entire circuit, or adding current transformers to realize relevant testing and protection of the circuit of the planar transformer 100.

[0056] The planar transformer 100 of the present application embodiment may also have multiple windings. Figure 3 As shown, the planar voltage generator 100 may include a plurality of Figure 1 The first circuit board 1 shown in the figure only shows three first circuit boards 1 for exemplary display. The assembly method of each first circuit board 1 and the second circuit board 2 can refer to the above, and will not be repeated here; the magnetic core 3 of the planar voltage device 100 can only include two magnetic divisions, which is equivalent to the above Figure 1 The multiple first magnetic divisions 31 shown are implemented as a single magnetic division, and the multiple second magnetic divisions 32 are implemented as another single magnetic division. After the first circuit boards 1 and the second circuit boards 2 are assembled, the two magnetic divisions can be directly aligned and bonded.

[0057] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. For ordinary technicians in this field, all equivalent structural changes made using the contents of this specification and drawings are also included in the patent protection scope of the present application.

[0058] In the description of the embodiments of the present application, terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the corresponding embodiments, rather than indicating or implying that a device or element must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation on the present application.

[0059] Although the terms "first, second", etc. are used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. In addition, the singular forms "one", "an", and "the" are intended to include plural forms as well. The terms "or" and "and / or" are interpreted as inclusive, or mean any one or any combination. Only when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way, an exception to this definition will occur.

Claims

1. A planar transformer, characterized in that: The planar transformer comprises: At least one first circuit board, wherein the first circuit board is provided with 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; a second circuit board, provided with a second through hole, a second winding portion and two second connecting portions, each of the second connecting portions being electrically connected to the second winding portion, the first circuit board and the second circuit board being stacked, and the first connecting portion being electrically connected to the second connecting portion 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 transformer; a magnetic core extending into the corresponding first through hole and the second through hole and forming an electromagnetic induction path with the first winding portion and the second winding portion, the magnetic core comprising a first magnetic portion and a second magnetic portion facing each other, the first magnetic portion and the second magnetic portion clamping the first circuit board and the second circuit board; A plurality of terminals, each terminal being electrically connected to the corresponding first connecting portion and the second connecting portion.

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

3. The planar transformer according to claim 1 or 2, characterized in that: The first through hole is a single hollow area formed in the first circuit board; The second through hole includes three hollow areas arranged in sequence and at intervals; 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, the second winding portion is arranged around a hollow area in the middle of the second through hole, and the two magnetic walls extend to the other two hollow areas of the second through hole; The first circuit board and the first winding portion are both located between the two magnetic walls.

4. The planar transformer according to claim 1 or 2, characterized in that: The first through hole includes three hollow areas arranged in sequence and at intervals; The second through hole includes three hollow areas arranged in sequence and at intervals; 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 middle hollow area of ​​the first through hole and a middle hollow area of ​​the second through hole, the first winding portion is arranged around a middle hollow area of ​​the first through hole, the second winding portion is arranged around a middle hollow area of ​​the second through hole, and 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.

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

6. The planar transformer according to claim 1, characterized in that: Along the stacking direction of the first circuit board and the second circuit board, the first connecting portion and the second connecting portion are aligned one by one.

7. The planar transformer according to claim 6, characterized in that: The first connecting portion includes a first via hole penetrating the first circuit board and a conductive layer at least arranged on the inner wall of the first via hole; the second connecting portion includes a second via hole penetrating the second circuit board and a conductive layer at least arranged on the inner wall of the second via hole; the terminal is inserted into the aligned first via hole and the second via hole, and contacts the conductive layer in the corresponding via hole.

8. The planar transformer according to claim 7, characterized in that: The conductive layer includes solder paste.

9. The planar transformer according to claim 1, characterized in that: The first connection portion is electrically connected to the second connection portion through a wiring, and the terminal is in direct contact with one of the first connection portion and the second connection portion to achieve electrical connection.

10. The planar transformer according to claim 1, characterized in that: A copper sheet or a current transformer is also arranged on the first circuit board.

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