Combined multi-layer PCB planar transformer and power converter

Abstract

The utility model belongs to the technical field of power transformers, and particularly relates to a combined type multi-layer PCB planar transformer and a power converter. Wherein the magnetic core comprises a first magnetic core and a second magnetic core, the multiple layers of PCBs are arranged between the first magnetic core and the second magnetic core, and a primary winding coil layer, a secondary winding coil layer and a shielding layer are arranged on the multiple layers of PCBs; the primary winding coil layers and the secondary winding coil layers are arranged at intervals in a staggered mode, and the shielding layers are arranged between the secondary winding coil layers and the primary winding coil layers.

Description

Technical Field

[0001] The utility model belongs to the technical field of power transformers, and in particular relates to a combined multi-layer PCB planar transformer and a power converter. Background Art

[0002] The statements in this section merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] The electronic component industry is developing towards high efficiency and miniaturization. As one of the most common and critical components, how to improve performance, save costs and miniaturize transformers has always been a concern for people in the industry.

[0004] At present, traditional transformers mainly use skeleton winding. The selected wires need to be wound on the skeleton layer by layer, and adhesive tape is required between the layers. After winding, the magnetic core and the skeleton are assembled and fixed with glue. The resulting transformer is large in size, high in height, and has relatively poor heat dissipation performance. At the same time, the loss is large, the efficiency is relatively low, and the electromagnetic interference (EMI) effect is poor. The use of PCB planar transformers can solve these problems well.

[0005] According to the inventors' understanding, in order to meet the requirements of inductance, input voltage and output voltage, the existing PCB planar transformer has a relatively large number of winding turns on the primary and secondary sides. If it is arranged with one layer of primary and secondary, the length and width of the PCB board will be much larger, resulting in the finished size of the transformer not meeting the requirements. At the same time, the existing planar transformer is mainly stacked by multiple PCB boards, such as the primary winding layer and the secondary winding layer are independent printed circuit boards, and a shielding plate is installed between each level of winding to achieve a shielding effect, but the overall thickness of the planar transformer will increase.

[0006] How to reduce leakage inductance and improve coupling performance, while reducing the volume of multilayer planar transformers to make the planar transformers thinner, is a difficult problem that needs to be solved urgently. Utility Model Content

[0007] In order to solve the above problems, the utility model proposes a combined multi-layer PCB planar transformer and a power converter. By superimposing multiple layers of PCB boards, the volume and cost of the planar transformer are reduced. The leakage inductance and coupling problems are solved by cross-connecting the primary winding coil and the secondary winding coil, thereby improving the coupling of the primary and secondary windings.

[0008] According to some embodiments, the first solution of the utility model provides a combined multi-layer PCB planar transformer, which adopts the following technical solution:

[0009] A combined multi-layer PCB planar transformer comprises a magnetic core and a multi-layer PCB board; wherein the magnetic core comprises a first magnetic core and a second magnetic core, the multi-layer PCB board is arranged between the first magnetic core and the second magnetic core, and the multi-layer PCB board is provided with a primary winding coil layer, a secondary winding coil layer and a shielding layer; the primary winding coil layer and the secondary winding coil layer are arranged in a staggered interval arrangement, and the shielding layer is arranged between the secondary winding coil layer and the primary winding coil layer.

[0010] As a further technical definition, the primary winding coil layer includes a first primary winding coil layer and a second primary winding coil layer; and the secondary winding coil layer is arranged between the first primary winding coil layer and the second primary winding coil layer.

[0011] Furthermore, the number of layers of the first primary winding coil layer, the secondary winding coil layer and the second primary winding coil layer is set to at least two layers.

[0012] Further, the shielding layer includes a first shielding layer disposed on the first primary winding coil layer close to the secondary winding coil layer and a second shielding layer disposed on the second primary winding coil layer close to the secondary winding coil layer.

[0013] As a further technical limitation, a first side column, a second side column and a middle column are arranged on the second magnetic core close to the PCB board side, and the first side column, the second side column and the middle column on the second magnetic core constitute a receiving groove.

[0014] Furthermore, each layer of PCB board is provided with a central hole, the central hole is sleeved on the central column, and each layer of PCB board is arranged in the accommodating groove.

[0015] Furthermore, a positioning column is provided on the first magnetic core close to the PCB board side, and a positioning hole matching the positioning column is opened on the middle column.

[0016] Furthermore, the first side column and the second side column close to the central column are arranged to form an arc-shaped recess.

[0017] Furthermore, each layer of PCB board is configured to have an arc-shaped convex position matching the arc-shaped concave position.

[0018] According to some embodiments, a second solution of the utility model provides a power converter, which adopts the following technical solution:

[0019] A power converter adopts the combined multi-layer PCB planar transformer provided in the first solution.

[0020] Compared with the prior art, the beneficial effects of the utility model are:

[0021] The utility model improves the coupling between the primary winding coil and the secondary winding coil by stacking multiple layers of PCB boards, cross-connecting the primary winding coil and the secondary winding coil, and arranging in series several layers of first primary winding coil, first shielding layer, several layers of secondary winding coil, second shielding layer and several layers of second primary winding coil; a receiving groove for placing the PCB board is provided on the second magnetic core, and the volume and cost of the overall PCB planar transformer are reduced by arranging each layer of PCB boards in the receiving groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0023] Figure 1 This is a structural schematic diagram of a combined multi-layer PCB planar transformer in Embodiment 1 of the present utility model;

[0024] Figure 2 This is an exploded structural schematic diagram of the combined multi-layer PCB planar transformer in the first embodiment of the utility model;

[0025] Figure 3 This is another exploded structural schematic diagram of the combined multi-layer PCB planar transformer in the first embodiment of the utility model;

[0026] Figure 4 This is a schematic diagram of the arrangement of a multi-layer PCB board in the first embodiment of the utility model;

[0027] Among them, 1. first magnetic core, 11. positioning column, 2. second magnetic core, 21. first side column, 22. second side column, 23. middle column, 231. positioning hole, 24. accommodating groove, 3. PCB board, 31. middle hole, 32. blind hole, 33. through hole. DETAILED DESCRIPTION

[0028] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention and cannot be understood as limitations on the present invention.

[0032] In the present utility model, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meanings of the above terms in the present utility model can be determined according to specific circumstances, and they cannot be understood as limitations on the present utility model.

[0033] Embodiment 1

[0034] The first embodiment of the utility model introduces a combined multi-layer PCB planar transformer.

[0035] like Figure 1 , Figure 2 and Figure 3 The combined multi-layer PCB planar transformer shown includes a magnetic core and a multi-layer PCB board 3, the magnetic core includes a first magnetic core 1 and a second magnetic core 2, and the multi-layer PCB board is arranged on the first magnetic core 1 and the second magnetic core 2; the second magnetic core 2 is composed of a first side column 21, a second side column 22 and a middle column 23, wherein the first side column 21, the second side column 22 and the middle column 23 form a receiving groove 24 for placing the PCB board 3 on the inner side of the second magnetic core 2; a positioning hole 231 is arranged at the center of the middle column 23, and a positioning column 11 matching the positioning hole 231 is arranged at the inner center of the first magnetic core 1.

[0036] It should be noted that the inner sides of the first side column 21 and the second side 22 are configured as arc-shaped concave positions, and each layer of PCB boards is configured as an arc-shaped convex position matching the arc-shaped concave positions.

[0037] like Figure 1 and Figure 2As shown, a center hole 31 matching the center column 23 is provided at the center of each layer of PCB board, and the center hole 31 is sleeved on the center column 23 to fix each layer of PCB board, and each layer of PCB board is arranged in the accommodating groove 24; winding coils are provided on the multi-layer PCB boards, and the winding arrangement of the winding coils is staggered and superimposed, that is, a first primary winding coil layer, a first shielding layer, a plurality of secondary winding coil layers, a second shielding layer and a plurality of second primary winding coil layers are arranged in a staggered manner.

[0038] It should be noted that the number of layers of the first primary winding coil, the secondary winding coil and the second primary winding coil is set to be consistent; and the number of layers of the first primary winding coil, the secondary winding coil and the second primary winding coil is set to at least two layers.

[0039] It should be noted that each layer of PCB boards is fixed by glue dispensing and pressing.

[0040] In this embodiment, the first magnetic core 1 and the second magnetic core 2 are made of manganese-zinc ferrite 96A with a wide temperature, wide frequency and low loss, which is suitable for use in power modules and can effectively reduce the risk of core cracking.

[0041] like Figure 4 As shown, the PCB board in this embodiment adopts an 8-layer board, adopts an immersion gold process, TG ≥ 150°C, a substrate FR-4, and an inner and outer layer copper thickness of 2OZ.

[0042] In this embodiment, if Figure 4 As shown, the first layer and the second layer are both set as the first primary winding coil layer, the third layer is set as the first shielding layer, the fourth layer and the fifth layer are both set as the secondary winding coil layer, the sixth layer is set as the second shielding layer, the seventh layer and the eighth layer are both set as the second primary winding coil layer, the top layer is provided with a plurality of pads and blind holes 32, the pads are used for external line connection, the blind holes 32 are used for internal connection between the layers, and the top layer and the bottom layer are both solder resist layers; wherein, the first layer, the second layer, the seventh layer and the eighth layer are connected in series through the blind holes 32 to form the primary winding coil N1, and the fourth layer and the fifth layer are connected in series through the blind holes 32 to form the secondary winding coil N3. Through the above-mentioned structural setting, the planar transformer in this embodiment can effectively reduce the leakage inductance, improve the coupling performance, reduce the overall volume, and make the transformer thinner.

[0043] It should be noted that the layers of the PCB board in this embodiment can be fixed by glue dispensing and pressing. In order to reduce cracking, the copper plating area of ​​the coils in each layer needs to be greater than 50% of the board and evenly wired.

[0044] It should be noted that the first shielding layer and the second shielding layer in this embodiment are both made of copper material to block electromagnetic waves and noise interference from the primary and secondary coils, and effectively resist interference from external electromagnetic waves.

[0045] The winding coil circuit of the transformer can be set according to the actual circuit conditions. For example, if there are more primary winding coils, four layers of winding coils are set. The secondary winding coil has fewer turns, larger current, and larger circuit width, so two layers are set. In order to improve the coupling performance, the combined multi-layer PCB planar transformer in this embodiment is arranged in a superimposed manner with 2 layers of primary, 2 layers of secondary, and 2 layers of primary.

[0046] like Figure 4 As shown, during installation, the 8-layer PCB board is sleeved on the middle column 23 through the through hole 33, and the I-type magnetic core cover is set on the top of the E-type magnetic core, and then wrapped with a layer of insulating tape, thereby forming an integral PCB multi-layer planar transformer. In order to facilitate the I-type magnetic core cover to be set on the E-type magnetic core, a positioning column can be set on the I-type magnetic core, and a positioning hole is set on the top of the corresponding E-type magnetic core, and the positioning column is plugged and fixed with the positioning hole. In addition, the side surface of the positioning column 11 can be circumferentially provided with a rubber ring, and the side wall of the positioning hole 231 is circumferentially provided with a concave hole corresponding to the rubber ring. When the positioning column 11 is plugged and fixed with the positioning hole 231, the rubber ring is snap-fitted with the concave hole.

[0047] In this embodiment, multiple layers of PCB boards are stacked, and the primary winding coil and the secondary winding coil are cross-connected, and several layers of first primary winding coil, first shielding layer, several layers of secondary winding coil, second shielding layer and several layers of second primary winding coil are arranged in series to improve the coupling between the primary winding coil and the secondary winding coil; a receiving groove for placing the PCB board is provided on the second magnetic core, and the volume and cost of the overall PCB planar transformer are reduced by arranging the PCB boards of each layer in the receiving groove.

[0048] Embodiment 2

[0049] The second embodiment of the present utility model introduces a power converter.

[0050] A power converter adopts the combined multi-layer PCB planar transformer introduced in the first embodiment.

[0051] The detailed principle is the same as the working principle of the combined multi-layer PCB planar transformer provided in Example 1, and will not be repeated here.

[0052] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

[0053] Although the above describes the specific implementation methods of the utility model in combination with the accompanying drawings, it is not intended to limit the scope of protection of the utility model. Technical personnel in the relevant field should understand that on the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the utility model.

Claims

1. A combined multi-layer PCB planar transformer, characterized in that: It comprises a magnetic core and a multi-layer PCB board; wherein the magnetic core comprises a first magnetic core and a second magnetic core, the multi-layer PCB board is arranged between the first magnetic core and the second magnetic core, and the multi-layer PCB board is provided with a primary winding coil layer, a secondary winding coil layer and a shielding layer; the primary winding coil layer and the secondary winding coil layer are arranged in a staggered interval, and the shielding layer is arranged between the secondary winding coil layer and the primary winding coil layer.

2. A combined multi-layer PCB planar transformer as claimed in claim 1, characterized in that: The primary winding coil layer includes a first primary winding coil layer and a second primary winding coil layer; the secondary winding coil layer is arranged between the first primary winding coil layer and the second primary winding coil layer.

3. A combined multi-layer PCB planar transformer as claimed in claim 2, characterized in that: The number of layers of the first primary winding coil layer, the secondary winding coil layer and the second primary winding coil layer is set to at least two layers.

4. A combined multi-layer PCB planar transformer as claimed in claim 2, characterized in that: The shielding layer includes a first shielding layer disposed on the first primary winding coil layer close to the secondary winding coil layer and a second shielding layer disposed on the second primary winding coil layer close to the secondary winding coil layer.

5. A combined multi-layer PCB planar transformer as claimed in claim 1, characterized in that: A first side column, a second side column and a middle column are arranged on the second magnetic core close to the PCB board side, and the first side column, the second side column and the middle column on the second magnetic core form a receiving groove.

6. A combined multi-layer PCB planar transformer as claimed in claim 5, characterized in that: Each layer of PCB board is provided with a central hole, the central hole is sleeved on the central column, and each layer of PCB board is arranged in the containing groove.

7. A combined multi-layer PCB planar transformer as claimed in claim 5, characterized in that: A positioning column is arranged on the first magnetic core close to the PCB board side, and a positioning hole matching the positioning column is opened on the middle column.

8. A combined multi-layer PCB planar transformer as claimed in claim 5, characterized in that: The first side column and the second side column close to the central column are arranged to form an arc-shaped recess.

9. A combined multi-layer PCB planar transformer as claimed in claim 8, characterized in that: Each layer of PCB board is configured to have an arc-shaped convex position matching the arc-shaped concave position.

10. A power converter, characterized in that: A combined multi-layer PCB planar transformer as described in any one of claims 1 to 9 is used.

Images