Transformer forming method, transformer and power supply

Abstract

The present application relates to the technical field of power supplies. Disclosed are a transformer forming method, a transformer and a power supply. The transformer comprises a circuit board and a magnetic core. The circuit board comprises a winding, and at least one first hole is provided in the circuit board, the first hole extending in the direction of thickness of the circuit board, and a hole wall of the first hole comprising a side wall of the winding. The magnetic core comprises at least one first magnetic post, the at least one first magnetic post corresponding to the at least one first hole on a one-to-one basis and passing through a corresponding first hole, the space between the first magnetic post and the first hole being filled with insulating material. In the transformer, the distance between the winding and the first hole and the distance between the magnetic core and the first hole are smaller, such that the maximized layout of the winding and the magnetic core is achieved in a limited space, reducing magnetic and copper losses and thereby effectively improving the efficiency of the power supply.

Description

Transformer forming method, transformer and power supply

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on April 1, 2024, with application number 202410390559.3 and application name “Transformer Forming Method, Transformer and Power Supply”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of power supply technology, and in particular to a transformer forming method, a transformer, and a power supply. Background Art

[0003] As the capacity of electronic devices continues to increase, the power of corresponding electronic components (such as chips) is also increasing. This leads to a sharp increase in current, resulting in more severe end-to-end (E2E) power supply efficiency losses, such as from the power supply end to the chip end. E2E power supply efficiency is positively correlated with the efficiency of the power supply. Power supplies typically include transformers to achieve voltage conversion. Power supply efficiency losses primarily come from two sources: copper loss in the transformer windings, which is related to winding volume; larger windings reduce copper loss; and magnetic loss in the transformer core, which is related to core volume; a thicker core reduces magnetic loss.

[0004] However, the windings and magnetic cores in current transformers cannot be maximized within a limited space, which makes it difficult to reduce copper and magnetic losses, thus affecting the improvement of power efficiency. Summary of the Invention

[0005] Some embodiments of the present application provide a transformer forming method, a transformer, and a power supply. The present application is introduced below from multiple aspects, and the embodiments and beneficial effects of the following multiple aspects can be referenced to each other.

[0006] In a first aspect, embodiments of the present application provide a transformer. The transformer includes a circuit board and a magnetic core. The circuit board includes a winding. The circuit board is provided with at least one first hole, extending along the thickness of the circuit board. The first hole walls include sidewalls of the winding. The magnetic core includes at least one first magnetic column, each corresponding to and extending through the first hole. The first magnetic column and the first hole are filled with insulating material.

[0007] According to an embodiment of the present application, the winding may include a conductive layer. Insulating material is filled between the first magnetic column and the first hole. Therefore, the hole wall of the first hole is not exposed to the outside, but is insulated from the outside world. That is, the winding can be insulated from the outside world by the insulating material, thereby meeting the safety insulation requirements of the winding. In this way, before the first hole is opened on the circuit board, there is no need to etch the conductive layer of the winding to avoid the opening position of the first hole, and the conductive layer of the winding can be fully laid in the circuit board. Since there is no need to consider the problem of position deviation of different layers of graphics caused by etching first and then pressing and opening the hole, and the insulating material can also effectively improve the insulation performance, it is beneficial to increase the volume of the winding, thereby maximizing the winding in a limited space and reducing copper loss.

[0008] Furthermore, the magnetic core includes at least one first magnetic column. This allows the first column to be pre-buried in the pre-defined first hole, and then the remaining components, excluding the first column, are installed to complete the core assembly and form the transformer. Consequently, there's no need to consider the accuracy of the hole placement; sufficient assembly clearance is sufficient. This allows for thicker first magnetic columns, maximizing the core's size within a limited space and minimizing magnetic losses.

[0009] In some embodiments, the winding includes at least one conductive layer, with an insulating layer disposed between two adjacent conductive layers. The hole wall of the first hole includes an inner sidewall of the conductive layer and an inner sidewall of the insulating layer. Along a first direction, the inner sidewall of the conductive layer is farther from the central axis of the first hole than the inner sidewall of the insulating layer. The first direction is perpendicular to the thickness of the circuit board.

[0010] Therefore, there can be more space between the conductive layer of the winding and the first magnetic column to fill with insulating material, so that the insulation performance of the transformer is better, which can meet the use requirements of voltage-resistant application scenarios (for example, 1500V voltage-resistant insulation requirements) and has a wide range of applications.

[0011] In some embodiments, along the first direction, the distance between the inner sidewall of the conductive layer and the inner sidewall of the insulating layer is less than or equal to 6 mils, i.e., less than or equal to 0.1524 mm, for example, 3 mils, 4 mils, 5 mils, etc. This ensures that the transformer has better insulation performance while also preventing the winding size from being too small, which helps reduce copper losses and thus improve efficiency.

[0012] In some embodiments, along the first direction, the distance between the outer circumference of the first magnetic column and the inner sidewall of the insulating layer is 0.05 mm-0.2 mm, for example, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, etc. This can meet the assembly requirements of the first magnetic column and can also be thicker, which is conducive to reducing magnetic loss and thus improving efficiency.

[0013] In some embodiments, the winding includes at least one conductive layer, with an insulating layer disposed between adjacent conductive layers. The first hole wall includes the inner sidewall of the conductive layer and the inner sidewall of the insulating layer. Along a first direction perpendicular to the thickness of the circuit board, the distance between the inner sidewall of the conductive layer and the inner sidewall of the insulating layer is zero. This allows the conductive layer to be larger while meeting the winding's safety insulation requirements, facilitating maximum winding layout within a limited space.

[0014] In some embodiments, along the first direction, the distance between the outer circumference of the first magnetic column and the wall of the first hole is 0.05 mm to 0.3524 mm, for example, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, etc. This can meet the safety insulation requirements of the winding while ensuring that the first magnetic column can be properly installed in the first hole.

[0015] In some embodiments, the magnetic core further includes a first magnet, the first magnet includes a first extension section, the first extension section extends along the thickness direction of the circuit board and is fixedly connected to the first magnetic column located in the first hole.

[0016] In some embodiments, along the thickness direction of the circuit board, an upper surface of the first magnetic column facing the first magnet is lower than an upper surface of the circuit board facing the first magnet.

[0017] In some embodiments, the first hole includes a first portion and a second portion that are interconnected, wherein the first portion is smaller than the second portion along a first direction, and the first direction is perpendicular to the thickness of the circuit board. The first magnetic post and the insulating material are disposed in the first portion, and the first extension extends along the thickness of the circuit board into the second portion and is fixedly connected to the first magnetic post.

[0018] Since the size of the second portion along the first direction is relatively large, it can accommodate a thicker first extension section, thereby further reducing magnetic loss.

[0019] In some embodiments, a magnetic conductive adhesive is filled between the upper surface of the first magnetic column and the plane where the upper surface of the circuit board is located, and the first extension section is fixedly connected to the first magnetic column via the magnetic conductive adhesive.

[0020] According to the embodiments of the present application, the magnetic adhesive possesses magnetic conductivity properties, such that it can function as a magnetic conductor similar to the first magnetic pillar. In other words, the magnetic adhesive acts as an extension of the first magnetic pillar. Because the magnetic adhesive can completely fill the gap between the upper surface of the first magnetic pillar and the plane of the upper surface of the circuit board, eliminating the need for assembly clearance, the portion of the magnetic pillar formed by the magnetic adhesive can be maximized, further increasing the volume of the magnetic core and reducing magnetic losses.

[0021] In some embodiments, along a first direction, the size of the first extension section is greater than or equal to the size of the first magnetic column, and the first direction is perpendicular to the thickness of the circuit board. This can further increase the volume of the magnetic core and reduce magnetic loss.

[0022] In some embodiments, along the thickness direction of the circuit board, a ratio between the size of the first magnetic pillar and the size of the circuit board is 0.8-1, for example, 0.8, 0.9, 1, etc.

[0023] In some embodiments, along the thickness direction of the circuit board, the size of the first magnetic column is larger than the size of the circuit board, and the difference between the two is less than or equal to 0.1 mm, for example, 0.1 mm, 0.09 mm, 0.08 mm, etc., thereby preventing the first magnetic column from interfering with the assembly of other devices (for example, chips, transistors and other components are mounted on the circuit board by tin printing).

[0024] In some embodiments, there are two first magnetic pillars and two first holes. The magnetic core further includes a first magnet and a second magnet, wherein the first magnet and the second magnet are located on opposite sides of the circuit board along the thickness direction of the circuit board, the first magnet is fixedly connected to one end of the two first magnetic pillars and the circuit board, and the second magnet is fixedly connected to the other end of the two first magnetic pillars.

[0025] In some embodiments, the insulating material is a resin or a prepreg.

[0026] In a second aspect, an embodiment of the present application provides a power supply, which includes the transformer provided in any embodiment of the first aspect of the present application.

[0027] It should be understood that the beneficial effects of the second aspect mentioned above can be referred to the description of the first aspect mentioned above and will not be repeated here.

[0028] In a third aspect, an embodiment of the present application provides a transformer forming method for forming the transformer provided in any embodiment of the first aspect of the present application, the method comprising:

[0029] Obtain a circuit board, the circuit board including at least one conductive layer and an opening area, the conductive layer extending from one end of the circuit board to the other end of the circuit board along a first direction and passing through the opening area, the first direction being perpendicular to the thickness direction of the circuit board. Open a first hole in the opening area along the thickness direction of the circuit board so that the inner side wall of the conductive layer is exposed at the hole wall of the first hole, and the conductive layer around the first hole forms a winding. Set a baffle at one end of the first hole, and place the first magnetic column of the magnetic core in the first hole. Fill the space between the first magnetic column and the first hole with insulating material. During the filling process, translate the first magnetic column along the first direction so that the insulating material is filled between the first magnetic column and the first hole. Complete the assembly of the magnetic core to obtain a transformer.

[0030] In the above method, the conductive layer of the circuit board does not need to avoid the opening position of the first hole in advance, but the first hole is opened first. In this way, the problem of graphic position deviation of different layers of conductive layers during the pressing process can be avoided, which is conducive to maximizing the winding and reducing copper loss. In addition, the magnetic core in the method provided by the present application includes at least one first magnetic column. The first magnetic column is first pre-buried in the first hole opened, and then the remaining part is installed, and finally the assembly of the magnetic core is completed to obtain a transformer. In this way, there is no need to consider the problem of the accuracy of the above-mentioned opening position, and sufficient assembly clearance can be reserved, which is conducive to maximizing the magnetic core and reducing magnetic loss.

[0031] In some embodiments, forming a winding of the conductive layer around the first hole includes: performing a material removal process on an inner sidewall of the conductive layer.

[0032] The conductive layer after the material removal process forms a winding. Therefore, there is more space to fill with insulating material, thereby improving the insulation performance and meeting the safety insulation requirements of the winding. In addition, since there is no need to consider the problem of position deviation of the graphics of different layers, it is beneficial to maximize the winding while meeting the safety insulation requirements of the winding, thereby reducing copper loss. In addition, by removing material from the conductive layer, burrs can also be removed, making the inner side wall of the conductive layer smoother, reducing safety risks, and avoiding affecting the subsequent assembly of the first magnetic column or interfering with the normal operation between different conductive layers.

[0033] In some embodiments, the material removal process includes etching inner sidewalls of the conductive layer.

[0034] In some embodiments, obtaining a circuit board further includes: alternately laminating and pressing conductive layers and insulating layers to obtain a circuit board. An opening area of ​​the circuit board is determined. A first hole is opened in the opening area along the thickness direction of the circuit board, such that the inner side wall of the insulating layer is exposed at the hole wall of the first hole. Material is removed from the inner side wall of the conductive layer such that, along a first direction, the inner side wall of the conductive layer is further away from the central axis of the first hole relative to the inner side wall of the insulating layer, the first direction being perpendicular to the thickness of the circuit board. This allows for more space to be filled with insulating material, thereby improving insulation performance and meeting the safety insulation requirements of the winding.

[0035] In some embodiments, insulating material is filled between the first magnetic column and the first hole by vacuum plugging. By utilizing vacuum adsorption and exhaust, the insulating material can be better filled between the first magnetic column and the first hole, thereby effectively avoiding the generation of bubbles, poor filling and other problems.

[0036] In some embodiments, the magnetic core further includes a first magnet and a second magnet. Completing the assembly of the magnetic core to obtain a transformer includes: fixing the second magnet to one end of the first magnetic column and the circuit board; and fixing the first magnet to the other end of the first magnetic column. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 shows an exemplary application scenario of a power supply in some embodiments of the present application;

[0038] FIG2A shows an exemplary structure of a secondary power supply in some technical solutions;

[0039] FIG2B shows a cross-sectional view of a transformer in a secondary power supply along the AA section in FIG2A in some technical solutions;

[0040] FIG3 shows an exemplary structure of a transformer in an embodiment of the present application;

[0041] FIG4 shows an exemplary structure of a transformer in one embodiment of the present application;

[0042] FIG5 shows an exemplary structure of a first magnetic column in some other embodiments of the present application;

[0043] FIG6 shows exemplary structures of grooves in other embodiments of the present application;

[0044] FIG7 shows an exemplary structure of a groove filled with magnetic conductive adhesive in some embodiments of the present application;

[0045] FIG8 shows an exemplary structure of a first magnet in some other embodiments of the present application;

[0046] FIG9 shows a flow chart of a transformer forming method according to an embodiment of the present application;

[0047] FIG10A shows an exemplary process 1 of transformer forming according to an embodiment of the present application based on FIG3 ;

[0048] FIG10B shows an exemplary second process of transformer forming according to FIG3 ;

[0049] FIG10C shows an exemplary third process of transformer forming according to FIG3 ;

[0050] FIG10D shows an exemplary fourth process of transformer forming according to FIG3 ;

[0051] FIG10E shows an exemplary fifth process of transformer forming according to FIG3 ;

[0052] FIG10F shows an exemplary sixth process of transformer forming according to FIG3 ;

[0053] FIG10G shows an exemplary seventh process of transformer forming according to FIG3 ;

[0054] FIG10H shows an exemplary eighth process of transformer forming according to FIG3 ;

[0055] FIG10I shows an exemplary ninth process of transformer forming according to an embodiment of the present application based on FIG3 ;

[0056] FIG10J shows an exemplary process 10 of transformer forming according to an embodiment of the present application based on FIG3 ;

[0057] FIG11A shows a transformer forming process 1 in some technical solutions according to FIG2B ;

[0058] FIG11B shows a second forming process of a transformer in some technical solutions according to FIG2B ;

[0059] FIG11C shows a third forming process of a transformer in some technical solutions based on FIG2B ;

[0060] FIG12A shows a transformer forming process 1 in some other technical solutions;

[0061] FIG12B shows a second transformer forming process in some other technical solutions;

[0062] FIG12C shows a third forming process of a transformer in some other technical solutions;

[0063] FIG13 shows an exemplary structure of a transformer in still other technical solutions. DETAILED DESCRIPTION

[0064] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0065] Embodiments of the present application provide a transformer and power supply. The transformer includes a printed circuit board (PCB) and a magnetic core mounted on the PCB, with the conductive layers on the PCB forming windings. It is understood that the power supply provided herein can be a primary power supply, a secondary power supply, or any other power source having the aforementioned transformer, and can be used to power electronic devices such as computing devices, wireless devices, and network system equipment.

[0066] Figure 1 shows an exemplary application scenario of a power supply in some embodiments of the present application. Referring to Figure 1 , a power supply system 1 generally includes a primary power supply 01 , a secondary power supply 02 , and a tertiary power supply 03 connected in cascade.

[0067] Primary power supply 01 can convert AC to DC and is therefore also called an AC / DC rectifier. For example, in the example shown in Figure 1, primary power supply 01 can convert 220V AC (i.e., 220Vac) to 48V DC (i.e., 48Vdc) for use in communications equipment or battery charging.

[0068] Secondary power supply 02 can convert DC to DC, and is therefore also referred to as a DC / DC conversion power supply. For example, in the example shown in Figure 1, secondary power supply 02 can convert 48VDC to a 12V DC voltage (i.e., 12VDC) or a 6V DC voltage (i.e., 6VDC), thereby powering the device's internal integrated circuits (e.g., control circuits, signal amplification circuits, etc.).

[0069] The tertiary power supply 03 can further convert the 12VDC into a smaller DC voltage. For example, in the example shown in Figure 1, one tertiary power supply 03 converts the 12VDC into a DC voltage of 1.2V-3.3V (i.e., 1.2Vdc-3.3Vdc), thereby supplying power to the chip 04; the other tertiary power supply 03 converts the 12VDC into a DC voltage of 0.75V (i.e., 0.75Vdc), thereby supplying power to the chip 04.

[0070] Both the primary power supply 01 and the secondary power supply 02 may include a transformer of the above-mentioned structure to realize the voltage conversion function. For ease of description, the following detailed description will be given by taking the secondary power supply as an example.

[0071] Fig. 2A shows an exemplary structure of a secondary power source 02 in some technical solutions. Fig. 2B shows a cross-sectional view of a transformer 10' in a secondary power source 02 along the AA section in Fig. 2A in some technical solutions.

[0072] Referring to Figures 2A and 2B , secondary power supply 02 includes a transformer 10'. Transformer 10' includes a circuit board 100' and a magnetic core 200'. Circuit board 100' includes a winding 110'. It will be understood that winding 110' is composed of multiple conductive layers 111' stacked on circuit board 100'. Figure 2B uses three stacked conductive layers 111' as an example. The three conductive layers 111' are stacked along the Z direction, and insulating layers 112' are provided between adjacent conductive layers 111' and on the outer surfaces of the conductive layers 111'. Circuit board 100' has two first holes 101' defined in it. The walls of the first holes 101' serve as the inner sidewalls 112A' of the insulating layer 112'. Winding 110' surrounds the outer periphery of the two first holes 101'. Magnetic core 200' includes two C-shaped magnetic pillars 210'. The two magnetic pillars 210' are located on opposite sides of circuit board 100'. The two ends of each magnetic column 210' correspond to the two first holes 101' one by one and are respectively inserted into the corresponding first holes 101'. The ends of the two magnetic columns 210' located in the same first hole 101' are fixedly connected to each other, and one of the magnetic columns 210' is also fixedly connected to the circuit board 100'.

[0073] The circuit board 100' can also be used to carry other electronic components, such as a metal-oxide-semiconductor field-effect transistor 20 (metal-oxide-semiconductor field-effect transistor, MOSFET, referred to as MOS tube), a control drive module 30, a pin 40 and a capacitor (not shown). Among them, the MOS tube 20 can be used to adjust the output voltage or current of the power supply. The control drive module 30 can be used to control the switch of the power supply, adjust the output voltage, current and other parameters. The pin 40 can be used to connect external devices, for example, to connect other power supplies, loads or other circuit modules, grounding, etc. Capacitors can be used for filtering and voltage stabilization to ensure the stability of the power supply output.

[0074] It is worth noting that there is a gap between the above-mentioned magnetic column 210' and the first hole 101', that is, the hole wall of the first hole 101' is exposed. Therefore, a certain distance needs to be maintained between the winding 110' and the first hole 101', for example, along the X direction, the distance between the inner side wall 111A' of the conductive layer 111' and the inner side wall 112A' of the insulating layer 112' (that is, the hole wall of the first hole 101') in the winding 110': the first distance G1, so as to meet the insulation distance requirements of the installation specifications of the winding 110' (hereinafter referred to as "safety insulation"). To this end, before opening the first hole 101', the conductive layer 111' needs to be etched first to avoid the opening position of the first hole 101', and then the conductive layer 111' needs to be pressed to obtain the circuit board 100', and then the first hole 101' needs to be opened on the circuit board 100'. Furthermore, during the process of laminating the conductive layers 111', the positions of the patterns etched between the different conductive layers 111' cannot be completely aligned. For example, some conductive layers 111' are closer to the opening of the first hole 101', while some conductive layers 111' are further away from the opening of the first hole 101'. Therefore, to reduce the impact of the positional deviation of the patterns of different layers and ensure that all conductive layers 111' meet safety insulation requirements, the first distance G1 is a minimum of 0.3 mm and is difficult to reduce further. Since the space for laying the conductive layer 111' in the circuit board 100' is limited and the first distance G1 is difficult to reduce, it is difficult to increase the dimension L1 of the conductive layer 111' along the X direction, the winding 110' cannot be maximized, and the copper loss is difficult to reduce.

[0075] In addition, a certain distance must be reserved between the magnetic pillar 210' and the first hole 101', for example, the single-side distance between the magnetic pillar 210' and the first hole 101': the second distance G2, to ensure that the magnetic core 200' can be properly assembled. Specifically, on the one hand, to ensure that the end size of the magnetic pillar 210' matches the size of the first hole 101', the second distance G2 needs to include an assembly gap; on the other hand, the opening position of the first hole 101' must also meet a high positional accuracy to ensure that both ends of the C-shaped magnetic pillar 210' can be simultaneously assembled with the two first holes 101' in a one-to-one correspondence. The second distance G2 also needs to include the opening position deviation. Taking all factors into consideration, the second distance G2 is difficult to reduce. For example, the minimum second distance G2 is 0.25mm. Due to the limited space in the circuit board 100' for the first hole 101', the aperture of the first hole 101' cannot be further increased. Limited by the second distance G2, a thicker magnetic pillar 210' cannot be used, the magnetic core 200' cannot be maximized, and the magnetic loss is difficult to reduce. The thickness of the magnetic column 210' can be measured by the dimension D1 of the portion of the magnetic column 210' located in the first hole 101' along the X direction. The larger the D1 value, the thicker the magnetic column 210' and the smaller the magnetic loss; the smaller the D1 value, the thinner the magnetic column 210' and the greater the magnetic loss.

[0076] Table 1 below shows the board area occupied by each component in the secondary power supply 02 on the circuit board 100 ′. Table 2 shows the loss ratio of each component in the secondary power supply 02 .

[0077] Table 1

[0078] Table 2

[0079] Referring to Table 1 and Table 2, when the magnetic core 200 ′ occupies 33% of the board area, the magnetic loss is 20%, the copper loss is 32%, and the loss generated by the transformer 10 ′ accounts for as high as 52%, which will seriously affect the improvement of the efficiency of the secondary power supply 02.

[0080] To address the aforementioned issues, the present application provides a transformer. Compared to the aforementioned transformer, the distance between the winding and the first hole, as well as the distance between the magnetic core and the first hole, in this transformer is smaller. This allows for a maximized layout of the winding and the magnetic core within a limited space, reduces magnetic loss and copper loss, and thereby effectively improves the efficiency of the power supply. This transformer is described in detail below with reference to the accompanying drawings.

[0081] FIG3 shows an exemplary structure of a transformer 10 according to an embodiment of the present application. Referring to FIG3 , the transformer 10 includes a circuit board 100 and a magnetic core 200 .

[0082] In which, the circuit board 100 includes at least one conductive layer 111 (for example, a copper foil layer), and at least one conductive layer 111 forms a winding 110. For example, FIG3 takes three layers of conductive layers 111 as an example, and an insulating layer 112 is provided between every two adjacent conductive layers 111, so as to avoid mutual interference between the two adjacent conductive layers 111. In some embodiments, the conductive layers 111 of different layers may have different electrical functions to be suitable for different application scenarios. In addition, the outside of the winding 110 (for example, the top wall, the bottom wall and the outer wall) also includes an insulating wall, so that the outside of the winding 110 (for example, the top wall, the bottom wall and the outer wall) is insulated from the outside world. In which, the top wall and the bottom wall of the winding 110 are two walls of the winding 110 that are opposite to each other along the Z direction, and the outer wall of the winding 110 is the side wall of the winding 110 facing away from the magnetic core 200.

[0083] At least one first hole 101 is also defined in the circuit board 100. First hole 101 is used to mount the magnetic core 200. First hole 101 extends along the Z direction, and its hole wall 1011 includes an inner sidewall 111A of the conductive layer 111 and an inner sidewall 112A of the insulating layer 112. In other words, the conductive layer 111 and first hole 101 may be connected.

[0084] The magnetic core 200 includes at least one first magnetic column 210 and the remaining portion excluding the first magnetic column 210. For example, in the example shown in FIG3 , there are two first magnetic columns 210 and two first holes 101, with the two first holes 101 corresponding one to the two first magnetic columns 210. The two first magnetic columns 210 extend along the Z direction and are respectively inserted into the corresponding first holes 101. Insulating material 300 is also filled between the first magnetic column 210 and the first hole 101 to insulate the inner side wall 111A of the winding 110 from the outside world. The remaining portion excluding the first magnetic column 210 includes a first magnet 220A and a second magnet 220B. Along the Z direction, the first magnet 220A and the second magnet 220B are respectively located on opposite sides of the circuit board 100. Furthermore, the first magnet 220A is fixedly connected to one end of the two first magnetic pillars 210, for example, by adhesive 600. The second magnet 220B is fixedly connected to the other ends of the two first magnetic pillars 210 and the circuit board 100, for example, by adhesive 600. The magnetic core 200 is generally shaped like a "mouth".

[0085] In the transformer 10 described above, the insulating material 300 is filled between the first magnetic column 210 and the first hole 101. Therefore, the hole wall 1011 of the first hole 101 is not exposed to the outside, but is insulated from the outside. In other words, the inner wall 111A of the winding 110 is insulated from the outside by the insulating material 300, thereby meeting the safety insulation requirements of the winding 110. As such, before the first hole 101 is formed in the circuit board 100, the conductive layer 111 does not need to be etched to avoid the opening position of the first hole 101; the conductive layer 111 can be completely laid out in the circuit board 100. Compared to the solution shown in the example of FIG. 2B above, in which the conductive layer is first etched and then pressed into a circuit board, and finally holes are opened, the present application does not need to consider the problem of positional deviation of different layers of graphics caused by etching first and then pressing and opening holes, and the insulating material 300 can also effectively improve the insulation performance, which is conducive to reducing the first distance G1, thereby making the dimension L1 of the conductive layer 111 along the X direction larger, thereby maximizing the winding 110 in a limited space and reducing copper loss. Among them, the first distance G1 refers to the distance between the inner side wall 111A of the conductive layer 111 and the inner side wall 112A of the insulating layer 112 in the winding 110 along the X direction (as an example of the first direction). Among them, the X direction can be perpendicular to the Z direction. For example, the X direction can be the length direction of the circuit board 100, or the X direction can also be the width direction of the circuit board 100.

[0086] In addition, the magnetic core 200 includes at least one first magnetic column 210 extending along the Z direction, and the remaining portion excluding the first magnetic column 210. Thus, the first magnetic column 210 can be pre-buried in the first hole 101, and then the remaining portion excluding the first magnetic column 210 (e.g., the first magnet 220A and the second magnet 220B) can be installed, finally completing the assembly of the magnetic core 200 and obtaining the transformer 10. Compared to the C-shaped magnetic column 210' in the example shown in FIG2B , the present application does not need to consider the accuracy of the hole position, and only requires a sufficient assembly gap. This helps to reduce the second distance G2, thereby allowing the use of a thicker first magnetic column 210. That is, the first magnetic column 210 has a larger dimension D1 along the X direction, thereby maximizing the size of the magnetic core 200 within a limited space and reducing magnetic loss. The second distance G2 refers to the minimum distance between the outer peripheral surface of the first magnetic column 210 and the hole wall 1011 of the first hole 101. For example, in the example shown in Figure 3, in the hole wall 1011 of the first hole 101, the inner side wall 111A of the conductive layer 111 and the inner side wall 112A of the insulating layer 112 are not flush along the X direction, and the inner side wall 111A of the conductive layer 111 is farther away from the central axis O of the first hole 101 than the inner side wall 112A of the insulating layer 112. At this time, the second distance G2 refers to the distance between the outer peripheral surface of the first magnetic column 210 and the inner side wall 112A of the insulating layer 112 along the X direction. In the example shown in Figure 4, in the hole wall 1011 of the first hole 101, the inner sidewall 111A of the conductive layer 111 and the inner sidewall 112A of the insulating layer 112 are flush along the X direction. At this time, the second distance G2 can refer to the distance between the outer peripheral surface of the first magnetic column 210 and the inner sidewall 111A of the conductive layer 111 along the X direction, or it can refer to the distance between the outer peripheral surface of the first magnetic column 210 and the inner sidewall 112A of the insulating layer 112 along the X direction.

[0087] Based on this, the transformer 10 provided in the embodiment of the present application can effectively improve power supply efficiency. For example, the first distance G1 can be reduced from 0.3mm to 0.1mm, and the second distance G2 can be reduced from 0.25mm to 0.15mm. In this case, the alternating current resistance (ACR) can be reduced by 20%, the peak efficiency can be increased by 0.3%-0.5%, and the full-load efficiency can be increased by more than 1%.

[0088] The specific structures of the winding 110 and the magnetic core 200 will be further described below with reference to the accompanying drawings.

[0089] Continuing with FIG. 3 , in some embodiments, along the X-direction, the inner sidewall 111A of the conductive layer 111 is farther from the central axis O of the first hole 101 than the inner sidewall 112A of the insulating layer 112. In other words, the first distance G1 is greater than 0. In this case, the hole wall 1011 of the first hole 101 is an uneven, curved surface, and the cross-section of the first hole 101 parallel to the XZ plane resembles a "N" shape.

[0090] Based on this, the sum of the first distance G1 and the second distance G2 is the safety insulation distance of the winding 110. Therefore, there is more space between the conductive layer 111 of the winding 110 and the first magnetic column 210 to fill with the insulating material 300, thereby improving the insulation performance of the transformer 10, meeting the requirements of withstand voltage applications (for example, 1500V withstand voltage insulation requirements), and having a wide range of applications. The second distance G2 is the assembly gap between the first magnetic column 210 and the first hole 101, ensuring that the first magnetic column 210 can be properly assembled into the first hole 101.

[0091] In some embodiments of the present application, the first distance G1 can be less than or equal to 6 mils, that is, less than or equal to 0.1524 mm, for example, 3 mils, 4 mils, 5 mils, etc. In this way, while ensuring that the transformer 10 has better insulation performance, the dimension L1 of the winding 110 along the X direction will not be too small, which is conducive to reducing copper losses and thus improving efficiency.

[0092] In some embodiments of the present application, the second distance G2 may be 0.05 mm-0.2 mm, for example, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, etc. In this way, the assembly requirements of the first magnetic pillar 210 can be met, and the dimension D1 of the first magnetic pillar 210 along the X direction can be larger, which is conducive to reducing magnetic loss and thus improving efficiency.

[0093] In the example shown in FIG3 , the third distance G3 between the winding 110 and the first magnetic column 210 along the Z direction is equal to the sum of the first distance G1 and the second distance G2. In some embodiments of the present application, the third distance G3 is greater than 0.05 mm and less than or equal to 0.3524 mm. Compared with the example shown in FIG2B , the third distance G3 = G1 + G2 = 0.3 mm + 0.25 mm = 0.55 mm. The third distance G3 in the embodiment of the present application is smaller, which is conducive to maximizing the winding 110 and the magnetic core 200, thereby reducing copper loss and magnetic loss and improving efficiency.

[0094] In some embodiments of the present application, after the first hole 101 is formed, the inner sidewall 111A of the conductive layer 111 may be subjected to a material removal process (e.g., etching) so that the inner sidewall 111A of the conductive layer 111 is recessed relative to the inner sidewall 112A of the insulating layer 112 in a direction away from the axis O, that is, a first distance G1 along the X direction between the inner sidewall 111A of the conductive layer 111 and the inner sidewall 112A of the insulating layer 112 is greater than 0.

[0095] In some other embodiments, along the X direction, the distance between the inner sidewall 111A of the conductive layer 111 and the axis O may be equal to the distance between the inner sidewall 112A of the insulating layer 112 and the axis O. In other words, the first distance G1 is equal to 0.

[0096] For example, Figure 4 illustrates an exemplary structure of a transformer 10 according to one embodiment of the present application. Referring to Figure 4 , the inner sidewall 111A of the conductive layer 111 and the inner sidewall 112A of the insulating layer 112 are aligned along the X-direction. In this case, the cross-sectional shape of the first hole 101 parallel to the XZ plane resembles a "mouth" shape.

[0097] Based on this, the second distance G2 is the safety insulation distance of the winding 110. It can be understood that the second distance G2 is not only the safety insulation distance of the winding 110, but also includes the assembly gap between the first magnetic column 210 and the first hole 101.

[0098] In some embodiments of the present application, the second distance G2 may be 0.05 mm-0.3524 mm, for example, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, etc. In this way, the safety insulation requirements of the winding 110 can be met while ensuring that the first magnetic column 210 can be properly installed in the first hole 101.

[0099] In the example shown in FIG4 , the third distance G3 between the winding 110 and the first magnetic column 210 along the Z direction is equal to the second distance G2. In some embodiments of the present application, the third distance G3 may be 0.05 mm to 0.3524 mm, for example, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, etc. Compared to the example shown in FIG2B , where the third distance G3 = G1 + G2 = 0.3 mm + 0.25 mm = 0.55 mm, the third distance G3 in the embodiment of the present application is smaller, which is conducive to maximizing the winding 110 and the magnetic core 200, thereby reducing copper loss and magnetic loss and improving efficiency.

[0100] Furthermore, since the inner side wall 111A of the conductive layer 111 and the inner side wall 112A of the insulating layer 112 are flush along the X direction, after the first hole 101 is opened on the circuit board 100, there is no need to remove material from the inner side wall 111A of the conductive layer 111, thereby reducing the number of molding steps and making the molding method simpler.

[0101] It is understood that the above figures only schematically illustrate the structure of the magnetic core 200. In other embodiments, the magnetic core 200 may also have other structures.

[0102] For example, as shown in Figures 3 and 4 above, in the embodiment of the present application, the height H1 of the first magnetic pillar 210 of the magnetic core 200 is equal to the thickness H2 of the circuit board 100. The height H1 of the first magnetic pillar 210 refers to the dimension of the first magnetic pillar 210 along the Z direction, and the thickness H2 of the circuit board 100 refers to the dimension of the circuit board 100 along the Z direction.

[0103] In some other embodiments, the height H1 of the first magnetic pillar 210 may not be equal to the thickness H2 of the circuit board 100. For example, FIG5 shows an exemplary structure of a first magnetic pillar 210 in some other embodiments of the present application. Referring to FIG5 , the height H1 of the first magnetic pillar 210 may be less than the thickness H2 of the circuit board 100. In some embodiments of the present application, when the height H1 of the first magnetic pillar 210 is less than or equal to the thickness H2 of the circuit board 100, the ratio between the height H1 of the first magnetic pillar 210 and the thickness H2 of the circuit board 100 may be, for example, 0.8-1, for example, 0.8, 0.9, 1, and so on.

[0104] Continuing to refer to Figure 5, since the height H1 of the first magnetic column 210 is less than the thickness H2 of the circuit board 100, the upper surface F1 of the first magnetic column 210 is lower than the upper surface F2 of the circuit board 100, and the first magnetic column 210 is recessed downward relative to the circuit board 100, thereby forming a groove 102. Herein, the upper surface of each component refers to the surface of each component facing the first magnet 220A. It can be understood that the space enclosed by the groove 102 is located within the space enclosed by the first hole 101, or in other words, the space enclosed by the first hole 101 includes the space enclosed by the groove 102, and the groove 102 is a part of the first hole 101. The first magnet 220A includes a first extension section 221A. Herein, the first extension section 221A can extend into the groove 102 along the Z direction and be fixedly connected to the first magnetic column 210 located in the first hole 101.

[0105] It will be appreciated that in the magnetic core 200 described above, the first extension section 221A functions similarly to the first magnetic column 210, generating electromagnetic induction with the winding 110. Therefore, the thicker the first extension section 221A, the more conducive it is to reducing magnetic loss. To prevent the groove 102 from limiting the thickness of the first extension section 221A, in some embodiments of the present application, the size of the groove 102 can be further increased to avoid the first extension section 221A extending into the groove 102, allowing the first extension section 221A to be configured as thick as possible, thereby further reducing magnetic loss.

[0106] For example, Figure 6 illustrates exemplary structures of grooves 102 in other embodiments of the present application. Referring to Figure 6 , along the X-direction, dimension D2 of groove 102 is greater than dimension D1 of first magnetic pillar 210. Because groove 102 is sufficiently large, first extension 221A can be configured as thick as possible, further increasing the volume of magnetic core 200 and reducing magnetic loss. For example, along the X-direction, dimension D3 of first extension 221A is greater than or equal to dimension D1 of first magnetic pillar 210.

[0107] In some implementations, the first hole 101 may be a stepped non-plating through hole (NPTH), thereby increasing the dimension D2 of the groove 102 along the X direction.

[0108] For example, in the example shown in FIG6 , the first hole 101 includes a first portion 101A and a second portion 101B that are interconnected. Along the X-direction, a dimension D4 of the first portion 101A is smaller than a dimension D5 of the second portion 101B. This can also be understood as follows: along the X-direction, the minimum distance (e.g., the second distance G2) between the hole wall 1011A of the first portion 101A and the outer circumference of the first magnetic pillar 210 is smaller than the minimum distance G4 between the hole wall 1011B of the second portion 101B and the outer circumference of the first magnetic pillar 210.

[0109] The first magnetic column 210 and the insulating material 300 are located in the first portion 101A. Thus, the first magnetic column 210, the insulating material 300, and the second portion 101B together form a groove 102. The bottom wall of the groove 102 is the first magnetic column 210 and the insulating material 300, and the sidewalls of the groove 102 are the hole walls 1011B of the second portion 101B. Since the dimension D5 of the second portion 101B along the X direction is relatively large, the dimension D2 of the groove 102 along the X direction is relatively large. It can be understood that D2 is equal to D5. Thus, the groove 102 can accommodate a thicker first extension section 221A, thereby further reducing magnetic loss. For example, in the example shown in FIG6 , along the X direction, the dimension D3 of the first extension section 221A is greater than the dimension D1 of the first magnetic column 210.

[0110] In some other implementations, the first hole 101 may not be a stepped hole. For example, as shown in FIG5 , after the insulating material 300 is filled between the first hole 101 and the first magnetic pillar 210, a portion of the insulating material 300 will be higher than the first magnetic pillar 210. This portion of the insulating material 300 is removed (for example, by laser removal) so that the insulating material 300 and the first magnetic pillar 210 are flush along the Z direction, exposing a portion of the hole wall of the first hole 101. At this point, the bottom wall of the groove 102 is the first magnetic pillar 210 and the insulating material 300, and the sidewall of the groove 102 is a portion of the hole wall of the first hole 101. In this way, the dimension D2 of the groove 102 along the X direction can also be made larger. It can be understood that D2 can be equal to the dimension of the first hole 101 along the X direction. As a result, the groove 102 can accommodate a thicker first extension section 221A, thereby further reducing magnetic loss. For example, along the X direction, the dimension D3 of the first extension section 221A can be equal to the dimension D1 of the first magnetic pillar 210.

[0111] In other embodiments of the present application, the groove 102 may be filled with magnetic adhesive to connect the first magnetic column 210 and the first magnet 220A via the magnetic adhesive to reduce magnetic loss.

[0112] For example, Figure 7 illustrates an exemplary structure of a groove 102 filled with magnetic adhesive 400 in some embodiments of the present application. Referring to Figure 7 , the magnetic adhesive 400 is filled in the groove 102. The upper surface F3 of the magnetic adhesive 400 is flush with the upper surface F2 of the circuit board 100. Alternatively, the magnetic adhesive 400 can be understood as completely filling the gap between the upper surface F1 of the first magnetic pillar 210 and the upper surface F2 of the circuit board 100. The magnetic adhesive 400 is in contact with the first magnet 220A.

[0113] On the one hand, the magnetic adhesive 400 is adhesive, allowing the first magnetic pillar 210 to be securely connected to the first magnet 220A via the magnetic adhesive 400. Furthermore, because the upper surface F3 of the magnetic adhesive 400 is flush with the upper surface F1 of the circuit board 100, the first extension section 221A of the first magnet 220A does not need to extend into the groove 102. The dimension D3 of the first extension section 221A along the X-direction is not restricted by the groove 102, which helps reduce magnetic loss. For example, along the X-direction, the dimension D3 of the first extension section 221A is greater than or equal to the dimension D1 of the first magnetic pillar 210.

[0114] On the other hand, the magnetic adhesive 400 also has magnetic conductivity properties, allowing it to perform the same magnetic conductivity function as the first magnetic pillar 210. In other words, the magnetic adhesive 400 acts as an extension of the first magnetic pillar 210. Because the magnetic adhesive 400 can completely fill the groove 102 without requiring assembly clearance, the magnetic pillar portion formed by the magnetic adhesive 400 can be maximized, further increasing the volume of the magnetic core 200 and reducing magnetic loss. For example, along the X-direction, the dimension D6 of the magnetic pillar portion formed by the magnetic adhesive 400 can be greater than or equal to the dimension D1 of the first magnetic pillar 210.

[0115] It will be appreciated that, along the X-direction, the dimension D6 of the magnetic adhesive 400 depends on the dimension D2 of the groove 102. For example, in this embodiment, the bottom wall of the groove 102 is the first magnetic pillar 210, and the sidewalls of the groove 102 are the insulating material 300. Along the X-direction, the dimension D2 of the groove 102 is equal to the dimension D1 of the first magnetic pillar 210. Therefore, along the X-direction, the dimension D6 of the magnetic adhesive 400 is also equal to the dimension D1 of the first magnetic pillar 210. In other embodiments, along the X-direction, the dimension D2 of the groove 102 may also be greater than the dimension D1 of the first magnetic pillar 210 (such as the groove 102 in the example shown in FIG. 6 above). Therefore, along the X-direction, the dimension D6 of the magnetic adhesive 400 may be greater than the dimension D1 of the first magnetic pillar 210.

[0116] It can also be understood that the example shown in Figure 7 above in which the upper surface F3 of the magnetic conductive adhesive 400 is flush with the upper surface F2 of the groove 102 is only for schematic illustration, and the present application is not limited thereto. In other embodiments, the upper surface F3 of the magnetic conductive adhesive 400 may also be lower than or higher than the upper surface F2 of the groove 102.

[0117] In other embodiments, the first magnet 220A may also be a flat plate structure placed perpendicular to the Z direction. The flat plate structure of the first magnet 220A may also be fixedly connected to the first magnetic column 210 via a magnetic adhesive 400 to reduce magnetic loss, which is not limited in this application.

[0118] It can be understood that the above embodiment only uses the case where the height H1 of the first magnetic column 210 is less than the thickness H2 of the circuit board 100 as an example, and the present application is not limited thereto. In some other alternative embodiments, the height H1 of the first magnetic column 210 may also be greater than the thickness H2 of the circuit board 100. In some embodiments of the present application, when the height H1 of the first magnetic column 210 is greater than the thickness H2 of the circuit board 100, the difference between the height H1 of the first magnetic column 210 and the thickness H2 of the circuit board 100 may be less than or equal to 0.1 mm, for example, 0.1 mm, 0.09 mm, 0.08 mm, etc., thereby preventing the first magnetic column 210 from interfering with the assembly of other devices (for example, components such as chips and transistors mounted on the circuit board 100 by tin printing).

[0119] Continuing with FIG. 3 , in the embodiment of the present application, the number of first magnetic pillars 210 of the magnetic core 200 is two. In other embodiments, the number of first magnetic pillars 210 may be greater or lesser (e.g., one, three, etc.), and this application does not impose any limitation thereto, as long as the magnetic core 200 can meet actual operating requirements.

[0120] 3 , in the embodiment of the present application, the first magnet 220A and the second magnet 220B of the magnetic core 200 are both flat plate structures placed perpendicular to the Z direction. In other embodiments, the first magnet 220A and the second magnet 220B may also have other structural forms.

[0121] For example, in the examples shown in Figures 5 to 7, the first magnet 220A can be a C-shaped structure. The first magnet 220A includes two first extension segments 221A and one second extension segment 222A. The two first extension segments 221A extend along the Z direction. The second extension segment 222A extends along the X direction. One end of the two extension segments 221A is connected to the two ends of the second extension segment 222A, respectively, and the other end of the two extension segments 221A is connected to the two first magnetic pillars 210, respectively.

[0122] As another example, FIG8 shows an exemplary structure of the first magnet 220A in other embodiments of the present application. Referring to FIG8 , the first magnet 220A may also have an L-shaped structure. The first magnet 220A includes a first extension section 221A and a second extension section 222A connected to each other. The first extension section 221A extends along the Z direction. The second extension section 222A extends along the X direction. The first extension section 221A and the second extension section 222A are respectively connected to the two first magnetic pillars 210.

[0123] In some embodiments of the present application, the second magnet 220B may also be a C-shaped structure or an L-shaped structure, which is not limited in this application. It is understood that the structure of the second magnet 220B is substantially the same as that of the first magnet 220A. For details, please refer to Figures 5 to 8 above and the related descriptions, and will not be repeated here.

[0124] The present application also provides a method for forming a transformer 10, which is used to form the above-mentioned transformer 10. In the method provided by the present application, the conductive layer 111 of the circuit board 100 does not need to avoid the opening position of the first hole 101 in advance (for example, the opening area S1 described below), but the first hole 101 is opened first. In this way, the problem of the graphic position deviation of different layers of the conductive layer 111 during the pressing process can be avoided, which is conducive to reducing the first distance G1, maximizing the winding 110, and reducing copper loss. In addition, the magnetic core 200 in the method provided by the present application includes at least one first magnetic column 210. The first magnetic column 210 is first pre-buried in the first hole 101 that has been opened, and then the remaining parts (for example, the first magnet 220A and the second magnet 220B) are installed, and finally the assembly of the magnetic core 200 is completed to obtain the transformer 10. In this way, there is no need to consider the problem of the accuracy of the above-mentioned opening position, and sufficient assembly clearance can be reserved, which is conducive to reducing the second distance G2, maximizing the magnetic core 200, and reducing magnetic loss.

[0125] It should be noted that the forming process of the two first magnetic columns 210 of the transformer 10 in this embodiment is essentially the same. To simplify the description, the forming process of the transformer 10 will be mainly described below based on the first magnetic column 210 on the left side of the transformer.

[0126] FIG9 is a flow chart of a method for forming transformer 10 according to an embodiment of the present application. FIG10A through FIG10J illustrate an exemplary process for forming transformer 10 according to an embodiment of the present application, based on FIG3 . Referring to FIG9 in conjunction with FIG10A through FIG10J and FIG3 , the forming method specifically includes the following steps.

[0127] S110 : Obtain a circuit board 100 , the circuit board 100 including an opening area S1 and at least one conductive layer 111 , the conductive layer 111 extending from one end to the other end of the circuit board 100 along the X direction and passing through the opening area S1 .

[0128] Referring to Figure 10A , taking three conductive layers 111 as an example, the three conductive layers 111 are alternately stacked along the Z direction, with an insulating layer 112 disposed between each adjacent conductive layer 111 to prevent interference between adjacent conductive layers 111. Each conductive layer 111 can extend from one end 100A of the circuit board 100 along the X direction to the other end 100B of the circuit board 100, passing through the opening area S1. In other words, the conductive layers 111 do not avoid the opening area S1; the opening area S1 is covered with the conductive layers 111.

[0129] In some embodiments of the present application, the circuit board 100 can be formed by alternately stacking and laminating the conductive layer 111 and the insulating layer 112. Alternatively, in some other alternative implementations, multiple discrete single-layer sub-boards or double-layer sub-boards can be pressed into the circuit board 100 with the required number of layers and thickness, which is not limited in this application.

[0130] Since the conductive layer 111 in the above-mentioned circuit board 100 is not formed into a circuit pattern by etching to avoid the opening area S1, but is completely laid in the circuit board 100, there will be no problem of pattern position deviation of different conductive layers 111 during the process of pressing and forming the circuit board 100.

[0131] S120 : opening a first hole 101 in the opening area S1 so that the inner sidewall 111A of the conductive layer 111 is exposed at the hole wall 1011 of the first hole 101 . The conductive layer 111 around the first hole 101 forms a winding 110 .

[0132] Referring to FIG. 10B in conjunction with FIG. 10A , in some embodiments of the present application, the solid portion of the opening area S1 can be removed by milling with a mechanical milling cutter, laser cutting, machining (e.g., drilling, CNC machining, etc.), etc., thereby forming the first hole 101. The first hole 101 extends along the Z direction.

[0133] Through first hole 101, the exposed inner wall 111A of conductive layer 111 and the inner wall 112A of insulating layer 112 can be directly observed. In other words, hole wall 1011 of first hole 101 includes inner wall 111A of conductive layer 111 and inner wall 112A of insulating layer 112. The conductive layer 111 surrounding first hole 101 forms winding 110. Several specific implementations of forming winding 110 with conductive layer 111 are described below.

[0134] Referring to FIG. 10C in conjunction with FIG. 10B , in some embodiments of the present application, a material removal process (e.g., etching) is performed on the inner sidewall 111A of the conductive layer 111, so that the inner sidewall 111A of the conductive layer 111 is recessed relative to the inner sidewall 112A of the insulating layer 112 in a direction away from the central axis O of the first hole 101. In other words, the first distance G1 is greater than 0. In this case, the cross-sectional shape of the first hole 101 parallel to the XZ plane is similar to a "N" shape.

[0135] The conductive layer 111 after material removal forms the winding 110. Since the conductive layer 111 is recessed, more space can be filled with insulating material (eg, insulating material 300), thereby improving insulation performance and meeting safety insulation requirements of the winding 110.

[0136] Furthermore, since there is no need to consider the positional offset of patterns on different layers, the first distance G1 can be set as small as possible while still meeting the safety insulation requirements of the winding 110. This increases the dimension L1 of the conductive layer 111 along the X direction, thereby reducing copper loss. For example, the first distance G1 can be less than or equal to 6 mils, such as 6 mils, 5 mils, 3 mils, 4 mils, and so on.

[0137] In addition, by removing material from the conductive layer 111 , burrs can be removed, making the inner sidewall 111A of the conductive layer 111 smoother, reducing safety risks, and avoiding affecting the subsequent assembly of the first magnetic column 210 or interfering with the normal operation of different conductive layers 111 .

[0138] In other embodiments of the present application, the inner sidewall 111A of the conductive layer 111 may not be subjected to material removal. After the first hole 101 is formed in the opening area S1, the conductive layer 111 in the opening area S1 is removed, and the remaining conductive layer 111 surrounding the first hole 101 forms the winding 110. In other words, the first distance G1 is equal to 0. For details, please refer to Figure 4 and the related description, which will not be repeated here. For the sake of consistency of description, the transformer forming method provided by the present application will continue to be described below using the winding 110 in the example shown in Figure 10C as an example.

[0139] S130 : Disposing a baffle 500 at one end of the first hole 101 , and placing the first magnetic column 210 in the first hole 101 .

[0140] Referring to Figure 10D , in some embodiments of the present application, the baffle 500 may be a tape disposed at the bottom end of the first hole 101 and adhered to the lower surface of the circuit board 100. The first magnetic pillar 210 is movably positioned within the first hole 101. In other words, the first magnetic pillar 210 can freely move within the first hole 101, for example, left and right along the X-direction. In other embodiments, the baffle 500 may also be other rigid plates, and this application is not limited thereto.

[0141] As previously mentioned, since the first magnetic pillar 210 is pre-placed independently within the first hole 101, there is no need to consider the accuracy of the opening position of the first hole 101. A sufficient assembly clearance is sufficient, which helps reduce the second distance G2. As a result, the first magnetic pillar 210 can be configured as thick as possible. That is, the dimension D1 of the first magnetic pillar 210 along the X-direction can be larger, thereby reducing magnetic loss. For example, the second distance G2 can be 0.05 mm to 0.2 mm, such as 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, and so on.

[0142] Based on this, the hole wall 1011 of the first hole 101 , the outer peripheral surface of the first magnetic column 210 and the baffle 500 can together form a filling groove, and the filling groove is used to fill the insulating material 300 .

[0143] S140 : filling the insulating material 300 between the first magnetic pillar 210 and the first hole 101 , and moving the first magnetic pillar 210 back and forth along the X direction during the filling process.

[0144] For example, during the process of filling the insulating material 300, the first magnetic pillar 210 can be moved along the X1 direction from the position shown in FIG. 10E to the position shown in FIG. 10F , such that the second right distance G2-R between the first magnetic pillar 210 and the first hole 101 is smaller than the second left distance G2-L. In this way, the right gap between the first magnetic pillar 210 and the first hole 101 can be filled with more insulating material 300 than the left gap. Then, the first magnetic pillar 210 is moved along the X2 direction from the position shown in FIG. 10F to the position shown in FIG. 10G , such that the second left distance G2-L between the first magnetic pillar 210 and the first hole 101 is larger than the second right distance G2-R. During this process, the insulating material 300 in the right gap between the first magnetic pillar 210 and the first hole 101 can be fully squeezed into every corner, while the left gap between the first magnetic pillar 210 and the first hole 101 can continue to be filled with more insulating material 300. Then, the first magnetic pillar 210 is moved along the X1 direction so that the insulating material 300 in the gap between the first magnetic pillar 210 and the first hole 101 on the left can be fully squeezed into every corner, and the gap between the first magnetic pillar 210 and the first hole 101 on the right can continue to be filled with more insulating material 300. This cycle is repeated until the space between the first magnetic pillar 210 and the first hole 101 is completely filled with insulating material 300. For example, as shown in FIG10H, the upper surface F4 of the insulating material 300 is flush with the upper surface F2 of the circuit board 100, and the gap between the first magnetic pillar 210 and the first hole 101 is completely filled with insulating material 300. The X1 direction and the X2 direction are both parallel to the X direction, and the X1 direction and the X2 direction are in opposite directions.

[0145] Because the first magnetic pillar 210 can move left and right along the X-direction during the filling process, there's no need to set the second distance G2 too large. By continuously adjusting the position of the first magnetic pillar 210, sufficient filling of the insulating material 300 can be achieved. Furthermore, the first magnetic pillar 210 can also squeeze the insulating material 300 during movement, ensuring a more complete filling of the insulating material 300. This allows the transformer 10 to achieve improved insulation performance, meeting the requirements of withstand voltage applications (e.g., 1500V withstand voltage insulation requirements), and broadening its application range.

[0146] In some embodiments of the present application, the insulating material 300 may be a resin or a prepreg.

[0147] In some embodiments of the present application, the insulating material 300 can be filled in a vacuum plugging manner, and vacuum adsorption and exhaust are used to enable the insulating material 300 to be better filled between the first magnetic column 210 and the first hole 101, thereby effectively avoiding the generation of bubbles, poor filling and other problems.

[0148] S150: Complete the assembly of the magnetic core 200 to obtain the transformer 10.

[0149] According to the above embodiment, the magnetic core 200 of the transformer 10 includes two first magnetic pillars 210. Based on the above steps S110-S140, a structure such as that shown in FIG10I can be obtained. Referring to FIG10I , the two first magnetic pillars 210 are respectively embedded in the two first holes 101. Insulating material 300 is filled between each magnetic pillar 210 and the corresponding first hole 101. The remaining components of the magnetic core 200 are then assembled based on the structure shown in FIG10I , thereby obtaining the transformer 10.

[0150] In this embodiment, the remaining portion of the magnetic core 200 of the transformer 10 includes a first magnet 220A and a second magnet 220B. For example, referring to FIG10J in conjunction with FIG10I , first, the end surfaces of the two first magnetic pillars 210 are treated to remove residual adhesive. Then, the second magnet 220B is fixedly connected to one end of the two first magnetic pillars 210 and the circuit board 100, for example, by adhesive 600. Then, referring to FIG3 , the first magnet 220A is fixedly connected to the other ends of the two first magnetic pillars 210, for example, by adhesive 600, to finally obtain the transformer 10.

[0151] It is understood that the above assembly process of the magnetic core 200 is only an example, and the present application is not limited thereto. In other embodiments, the magnetic core 200 may also have other structural forms, so the specific assembly process of the magnetic core 200 may be different.

[0152] The method for forming the transformer 10 described above first opens a first hole 101 on a circuit board 100 fully covered with a conductive layer 111. The magnetic column 210 is then embedded in the first hole 101, and finally the remaining portion of the magnetic core 200 (e.g., the first magnet 220A and the second magnet 220B) is assembled to obtain the transformer 10. Compared to the solution shown in the example of FIG. 2B , which first etches the conductive layer 111' to avoid the opening area S1 before opening the first hole 101', in the embodiment of the present application, the conductive layer 111 is not etched before opening the first hole 101 on the circuit board 100. That is, the conductive layer 111 does not need to avoid the opening area S1 in advance. This effectively avoids the problem of positional deviation of the patterns of different layers, thereby enabling the first distance G1 to be set as small as possible, resulting in a larger volume of the winding 110 and lower copper loss.

[0153] In addition, compared to the solution of directly assembling two C-shaped magnetic columns 210' in the example shown in Figure 2B, in the embodiment of the present application, by pre-burying the first magnetic column 210 in the first hole 101 and then assembling the remaining parts of the magnetic core 200 (for example, the first magnet 220A and the second magnet 220B), the influence of the opening position accuracy of the first hole 101 can be eliminated, so that the second distance G2 can be set as small as possible, the first magnetic column 210 can be thicker, and the magnetic loss is lower. In summary, the transformer 10 formed by the molding method provided by the present application can effectively improve the power supply efficiency. Moreover, in the process of filling the insulating material 300, the first magnetic column 210 can move left and right along the X direction, so that the insulating material 300 can be filled more fully, thereby effectively improving the insulation performance of the transformer 10.

[0154] In some embodiments of the present application, after the transformer 10 is formed by the above-mentioned transformer forming method, other devices (for example, MOS tube 20, control drive module 30 and other devices) can be assembled through surface mounting technology (SMT) to obtain a secondary power supply 02.

[0155] The following describes a comparison between the transformer forming method provided in the embodiment of the present application and the transformer forming methods in some other technical solutions.

[0156] 11A to 11C illustrate the forming process of the transformer 10 ′ in some technical solutions based on FIG. 2B .

[0157] Referring to Figures 11A to 11C, and in combination with Figure 2B, first, a circuit board 100' is provided. The circuit board 100' is formed by pressing together multiple layers of sub-boards 100A' on which circuit patterns have been etched. Specifically, the conductive layer 111' of each layer of sub-board 100A' is first etched separately so that the conductive layer 111' can avoid the edge of the opening area S1 (for example, as shown by the two dotted lines in Figure 11A) to avoid damage to the copper foil during subsequent openings, while meeting safety insulation requirements. The multi-layer sub-boards 100A' are then pressed together to obtain the circuit board 100'. Among them, the multiple layers of stacked and pressed conductive layers 111' form a winding 110'. Then, the opening area S1 of the circuit board 100' is processed by a milling cutter to form a first hole 101'. Next, the ends of the C-shaped magnetic columns 210 ′ are passed through the first holes 101 ′ so that the two C-shaped magnetic columns 210 ′ can be mounted in a buckled manner, and finally the transformer 10 ′ as shown in FIG. 2B is obtained.

[0158] In the above-mentioned forming method, the graphic positions between different conductive layers 111' cannot be completely aligned. For example, some conductive layers 111' are closer to the opening area S1, while some conductive layers 111' are farther away from the hole area S1. Therefore, the minimum value of the first distance G1 is 0.3mm, thereby reducing the impact of the position deviation of the graphics of different layers and ensuring that all conductive layers 111' can meet the safety insulation distance requirements. In addition, a certain assembly distance needs to be reserved between the magnetic column 210' and the first hole 101' so that the end of the magnetic column 210' can be inserted into the first hole 101', and the opening position of the first hole 101' (for example, the size of the opening area S1) also needs to meet a high position accuracy to ensure that the two ends of the C-shaped magnetic column 210' can be assembled with the two first holes 101' at the same time. Taking all factors into consideration, the minimum value of the second distance G2 is 0.25mm. Thus, the third distance G3 = G1 + G2 = 0.3 + 0.25 = 0.55 mm, so that the layout area of ​​the winding 110 ′ and the magnetic core 200 ′ cannot be further increased within the limited space, and the copper loss and the magnetic loss are difficult to reduce.

[0159] Figures 12A to 12C show the forming process of the transformer 10" in other technical solutions. Referring to Figures 12A to 12C, the conductive layer 111" of each layer of the sub-board 100A" is first etched separately so that the conductive layer 111" can avoid the opening area S1. Then the opening area S1 of the multi-layer sub-board 100A" is opened to form the first hole 101". The magnetic column 210" is placed in the first hole 101", and then a semi-cured sheet 113" is set between the two adjacent sub-boards 100A", and the multi-layer sub-boards 100A" are pressed. During the pressing process, the semi-cured sheet 113" will be squeezed to fill the gap between the magnetic column 210" and the first hole 101". Finally, the remaining parts of the magnetic core 200" are assembled to obtain the transformer 10".

[0160] Based on the forming process of the above-mentioned transformer 10", it is not difficult to find that this solution also needs to consider the impact of the position deviation of the patterns of different layers. In addition, the opening size and position tolerance also need to be considered. In summary, the third distance G3 is at least 1mm, which still cannot achieve the maximum layout of the winding 110" and the magnetic core 200", and it is difficult to reduce copper loss and magnetic loss.

[0161] FIG13 shows an exemplary structure of a transformer 10″′ in some other technical solutions. Referring to FIG13 , in the transformer 10″′, the conductive layer 111″′ does not need to avoid the opening position of the first hole 101″′ in advance. Instead, the first hole 101″′ is opened first, and then the conductive layer 111″′ is etched. Then, the magnetic core 200″′ is installed. Finally, the molding compound 300″′ is filled to mold the transformer 10″′ as a whole. The molding compound 300″′ will be filled between the magnetic column 210″′ and the first hole 101″′ to play an insulating role.

[0162] However, since the magnetic core 200'' is assembled first and then the molding compound 300'' is filled, the gap between the magnetic column 210'' and the first hole 101'' is fixed, so it is difficult to fully fill the molding compound 300''. In addition, there is an assembly error in the magnetic core 200'', and the outer peripheral surface of the magnetic column 210'' is easily attached to the hole wall of the first hole 101'', thereby forming a dead angle area. For example, when the outer peripheral surface of the magnetic column 210'' is attached to the right hole wall of the first hole 101'', the S2 area is a closed area, and the molding compound 300'' cannot be filled into the S2 area. Based on this, the transformer 10'' has a voltage resistance risk and is only suitable for low-voltage scenarios, with a small range of applications. In addition, in order to reduce the impact of the assembly error of the magnetic core 200'' on the filling of the molding compound 300'', the second distance G2 is difficult to further reduce, and the maximization of the magnetic core 200'' cannot be achieved, and the magnetic loss is large.

[0163] In some other technical solutions, the first distance G1 can also be shortened by improving the processing accuracy of the circuit board 100'. However, on the one hand, the current processing equipment has limited capabilities. For example, the position accuracy and dimensional accuracy of machining such as milling / drilling are limited, which is not conducive to reducing the first distance G1. On the other hand, as mentioned above, due to the limitations of the molding process of the circuit board 100', there is a problem of position deviation of different layers of graphics, which is also not conducive to reducing the first distance G1. In summary, in this solution, the first distance G1 can only be reduced from 0.3mm to 0.25mm, the benefits are limited, the winding still cannot be maximized, and the copper loss is large. In addition, this method cannot reduce the second distance G2, it is difficult to maximize the magnetic core, and the magnetic loss is large.

[0164] In summary, none of the above solutions can achieve the maximum layout of the winding and the magnetic core within a limited space. In the present application, on the one hand, before the first hole 101 is opened on the circuit board 100, the conductive layer 111 is not etched, that is, the conductive layer 111 does not need to avoid the opening area S1, which can effectively avoid the problem of graphic position deviation of different layers of conductive layers, so that the first distance G1 can be set as small as possible, the volume of the winding 110 is larger, and the copper loss is lower. On the other hand, in an embodiment of the present application, by pre-burying the first magnetic column 210 in the first hole 101 and then assembling the remaining parts of the magnetic core 200 (for example, the first magnet 220A and the second magnet 220B), the influence of the opening position accuracy of the first hole 101 can be eliminated, so that the second distance G2 can be set as small as possible, the first magnetic column 210 can be thicker, and the magnetic loss is lower. Moreover, during the process of filling the insulating material 300, the first magnetic column 210 can move back and forth along the X direction, so that the insulating material 300 is filled more fully, thereby making the insulation performance of the transformer 10 better, and being able to meet the use requirements of voltage-resistant application scenarios (for example, 1500V voltage-resistant insulation requirements), and having a wide range of applications. In summary, compared with the above-mentioned forming method, the forming method of the transformer 10 of the present application can form a larger volume of windings 110 and magnetic cores 200, so that the final formed transformer 10 can have lower copper loss and magnetic loss, higher efficiency and better insulation performance, and a wide range of applications.

[0165] The above describes the implementation methods of the present application by means of specific specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to the implementation methods. On the contrary, the purpose of introducing the application in conjunction with the implementation methods is to cover other options or modifications that may be extended based on the claims of the present application. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details are omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0166] In the description of this application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "outside", "inside", "circumferential", "radial", "axial", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0167] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "dispose," "install," "connect," and "fit" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0168] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A transformer, characterized in that: Includes circuit board and magnetic core, including: The circuit board includes a winding, and at least one first hole is formed on the circuit board. The first hole extends along the thickness direction of the circuit board, and a hole wall of the first hole includes a side wall of the winding; The magnetic core includes at least one first magnetic column, which corresponds to the at least one first hole one by one and is inserted into the corresponding first hole. Insulating material is filled between the first magnetic column and the first hole.

2. The transformer according to claim 1, characterized in that The winding includes at least one conductive layer, an insulating layer is provided between two adjacent conductive layers, and the hole wall of the first hole includes an inner side wall of the conductive layer and an inner side wall of the insulating layer; Along a first direction, an inner sidewall of the conductive layer is farther away from a central axis of the first hole than an inner sidewall of the insulating layer, and the first direction is perpendicular to a thickness direction of the circuit board.

3. The transformer according to claim 2, characterized in that Along the first direction, a distance between an inner sidewall of the conductive layer and an inner sidewall of the insulating layer is less than or equal to 6 mil.

4. The transformer according to claim 2, characterized in that Along the first direction, the distance between the outer peripheral surface of the first magnetic column and the inner sidewall of the insulating layer is 0.05 mm-0.2 mm.

5. The transformer according to claim 1, characterized in that The winding includes at least one conductive layer, an insulating layer is provided between two adjacent conductive layers, and the hole wall of the first hole includes an inner side wall of the conductive layer and an inner side wall of the insulating layer; Along a first direction, a distance between an inner sidewall of the conductive layer and an inner sidewall of the insulating layer is 0, and the first direction is perpendicular to a thickness direction of the circuit board.

6. The transformer according to claim 5, characterized in that Along the first direction, the distance between the outer circumference of the first magnetic column and the hole wall of the first hole is 0.05 mm-0.3524 mm.

7. The transformer according to claim 1, characterized in that The magnetic core further includes a first magnet, which includes a first extension section. The first extension section extends along the thickness direction of the circuit board and is fixedly connected to the first magnetic column located in the first hole.

8. The transformer according to claim 7, characterized in that Along the thickness direction of the circuit board, an upper surface of the first magnetic column facing the first magnet is lower than an upper surface of the circuit board facing the first magnet.

9. The transformer according to claim 8, characterized in that The first hole includes a first portion and a second portion that are connected to each other, and along a first direction, a size of the first portion is smaller than a size of the second portion, and the first direction is perpendicular to a thickness direction of the circuit board; The first magnetic column and the insulating material are arranged in the first part, and the first extension section extends into the second part along the thickness direction of the circuit board and is fixedly connected to the first magnetic column.

10. The transformer according to claim 8, characterized in that A magnetic conductive adhesive is filled between the upper surface of the first magnetic column and the plane where the upper surface of the circuit board is located, and the first extension section is fixedly connected to the first magnetic column through the magnetic conductive adhesive.

11. The transformer according to claim 9 or 10, characterized in that: Along a first direction, a size of the first extension section is greater than or equal to a size of the first magnetic column, and the first direction is perpendicular to a thickness direction of the circuit board.

12. The transformer according to claim 8, characterized in that Along the thickness direction of the circuit board, a ratio between the size of the first magnetic column and the size of the circuit board is 0.8-1.

13. The transformer according to claim 1, characterized in that Along the thickness direction of the circuit board, the size of the first magnetic column is larger than the size of the circuit board, and the difference between the two is less than or equal to 0.1 mm.

14. The transformer according to claim 1, characterized in that The number of the first magnetic columns is two, the number of the first holes is two, The magnetic core also includes a first magnet and a second magnet. Along the thickness direction of the circuit board, the first magnet and the second magnet are respectively located on opposite sides of the circuit board. The first magnet is respectively fixedly connected to one end of the two first magnetic columns and the circuit board, and the second magnet is respectively fixedly connected to the other end of the two first magnetic columns.

15. The transformer according to claim 1, characterized in that The insulating material is resin or prepreg.

16. A power supply, characterized in that: The power supply comprises the transformer according to any one of claims 1 to 15.

17. A transformer forming method, used for forming the transformer according to any one of claims 1 to 15, characterized in that: The method comprises: Obtain a circuit board, the circuit board comprising at least one conductive layer and an opening area, the conductive layer extending from one end of the circuit board to the other end of the circuit board along a first direction and passing through the opening area; the first direction is perpendicular to a thickness direction of the circuit board; A first hole is opened in the opening area along the thickness direction of the circuit board, so that the inner side wall of the conductive layer is exposed at the hole wall of the first hole, and the conductive layer around the first hole forms a winding; Disposing a baffle at one end of the first hole, and placing the first magnetic column of the magnetic core in the first hole; Filling an insulating material between the first magnetic pillar and the first hole, and during the filling process, translating the first magnetic pillar along the first direction so that the insulating material is filled between the first magnetic pillar and the first hole; The assembly of the magnetic core is completed to obtain the transformer.

18. The method according to claim 17, characterized in that The forming of a winding of the conductive layer around the first hole comprises: performing material removal processing on an inner sidewall of the conductive layer.

19. The method according to claim 18, characterized in that The material removal process includes: etching the inner sidewall of the conductive layer.

20. The method according to claim 18, wherein The obtaining of the circuit board further includes: alternately laminating and pressing the conductive layer and the insulating layer to obtain the circuit board; and determining the opening area of ​​the circuit board; Opening the first hole in the opening area along the thickness direction of the circuit board so that the inner side wall of the insulating layer is exposed at the hole wall of the first hole; Material is removed from the inner sidewall of the conductive layer so that the inner sidewall of the conductive layer is farther away from the central axis of the first hole than the inner sidewall of the insulating layer along a first direction, wherein the first direction is perpendicular to the thickness of the circuit board.

21. The method according to claim 17, wherein The insulating material is filled between the first magnetic column and the first hole in a vacuum plugging manner.

22. The method according to claim 17, wherein The magnetic core further includes a first magnet and a second magnet. The transformer obtained by assembling the magnetic core includes: The second magnet is fixedly connected to one end of the first magnetic column and the circuit board; The first magnet and the other end of the first magnetic column are fixedly connected.

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