Magnetic element

Abstract

The application discloses a magnetic element, which comprises a cover plate and a magnetic core body, the magnetic core body comprises a first side column and a second side column, and a middle column connected between the first side column and the second side column, and a winding is wound on the middle column; and the cover plate is fixed on the upper surfaces of the first side column and the second side column. The application realizes the small size of the magnetic element and reduces the cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnetic components, in particular to a magnetic element. BACKGROUND

[0002] With the increase of switching frequency, miniaturization of magnetic elements has become a trend in the industry, Figure 1 The existing multi-output transformer structure is composed of a magnetic core 101, an SMD skeleton 102 and a wire package 103. However, the SMD skeleton increases the area occupied by the magnetic element and the cost. SUMMARY

[0003] Therefore, the present application provides a small-size transformer to reduce the production cost.

[0004] According to a first aspect of the present application, a magnetic element is provided, comprising a cover plate and a magnetic core body, the magnetic core body comprising a first side column and a second side column, and a middle column connected between the first side column and the second side column, and a winding wound on the middle column; the cover plate is fixed on the upper surface of the first side column and the second side column.

[0005] Preferably, the magnetic core body is an I-shaped type.

[0006] Preferably, the winding comprises a first winding and a second winding, the first winding is wound on a first part of the middle column close to the first side column, and the second winding is wound on a second part of the middle column close to the second side column.

[0007] Preferably, the magnetic core body further comprises a boss, the boss is located on the middle column and separates the first winding and the second winding wound on the middle column.

[0008] Preferably, the inductance between the first winding and the second winding is adjusted by changing the shape of the boss.

[0009] Preferably, the boss is formed by extending on one surface or multiple surfaces of the middle column.

[0010] Preferably, the boss is located on the lower surface of the middle column away from the cover plate.

[0011] Preferably, the side surface of the boss does not exceed the side surface of the middle column, and the side surface of the middle column is connected with the lower surface.

[0012] Preferably, the boss has a concave structure, comprising a first part located on the lower surface of the middle column away from the cover plate and a second part located on the side surface of the middle column, and the side surface of the middle column is connected with the lower surface.

[0013] Preferably, the boss is in a square ring structure, comprising a first portion on the lower surface of the center column away from the cover plate, a second portion on the side surface of the center column, and a third portion on the upper surface of the center column close to the cover plate.

[0014] Preferably, the side surface of the boss does not exceed the side surface of the first and second edge columns.

[0015] Preferably, the pins of the magnetic element are located on the bottom surface of the first and second edge columns, and the upper surface of the first and second edge columns is opposite to the bottom surface.

[0016] Preferably, the pins include first type pins and second type pins, the first type pins are located on the bottom surface of the first edge column, and the second type pins are located on the bottom surface of the second edge column.

[0017] Preferably, the head and tail ends of the first winding are spot-welded on the corresponding first type pins, and the head and tail ends of the second winding are spot-welded on the corresponding second type pins.

[0018] Preferably, the number of pins is not less than 4.

[0019] Preferably, at least 2 windings are wound around the center column.

[0020] Preferably, an air gap is left between the cover plate and the first and second edge columns of the magnetic core.

[0021] Preferably, an air gap is left in the cover plate.

[0022] Preferably, the cover plate is made of a powder core material.

[0023] Preferably, the magnetic core element has no air gap.

[0024] Preferably, when the number of turns of the first winding and the second winding is different, the magnetic element is a transformer.

[0025] Preferably, when the number of turns of the first winding and the second winding is the same, the magnetic element is an inductor.

[0026] Preferably, the magnetic core body is made of nickel-zinc ferrite.

[0027] Preferably, the cover plate is made of nickel-zinc ferrite or MnZn ferrite.

[0028] Preferably, the pins are formed by electroplating on the bottom surface of the first and second edge columns.

[0029] Preferably, the bottom surface of the first and second edge columns has a recess formed by etching.

[0030] Preferably, the pin is formed by attaching a metal sheet to the recess.

[0031] The magnetic component provided by this invention uses nickel-core ferrite as its core and forms pins at the bottom of the core, resulting in a frameless magnetic component structure. This achieves miniaturization of the magnetic component and reduces costs. Furthermore, multiple pins can be configured as needed to achieve multiple outputs. Additionally, by providing bosses on the central pillar of the core to separate the primary and secondary windings, leakage inductance is generated between them. This leakage inductance can be used as a resonant inductor to facilitate soft switching, thereby reducing the number of magnetic components in the circuit. Attached Figure Description

[0032] Figure 1 This is a structural diagram of a magnetic component in the prior art;

[0033] Figure 2a and 2b This is a structural diagram of a magnetic element according to a first embodiment of the present invention;

[0034] Figure 3a and 3b This is a structural diagram of a magnetic element according to a second embodiment of the present invention;

[0035] Figure 4 This is a structural diagram of a magnetic element according to a third embodiment of the present invention;

[0036] Figure 5 This is a structural diagram of a magnetic element according to a fourth embodiment of the present invention;

[0037] Figure 6 This is a cross-sectional view of a magnetic element according to a fifth embodiment of the present invention. Detailed Implementation

[0038] The invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same components are indicated by similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale. Furthermore, some well-known parts may not be shown. For brevity, the structure obtained after several steps may be depicted in a single drawing. Many specific details of the invention are described below, such as the structure, materials, dimensions, processing methods, and techniques of each component, to provide a clearer understanding of the invention. However, as those skilled in the art will understand, the invention may be implemented without adhering to these specific details.

[0039] The application provides a magnetic element, comprising a cover plate and a magnetic core body, the magnetic core body comprising a first side column and a second side column, and a middle column connected between the first side column and the second side column, and a winding wound on the middle column, and the cover plate is fixed on the upper surface of the first side column and the second side column.

[0040] Specifically, Figure 2a and 2b The application provides a magnetic element, comprising a cover plate and a magnetic core body, the magnetic core body comprising a first side column and a second side column, and a middle column connected between the first side column and the second side column, and a winding wound on the middle column, and the cover plate is fixed on the upper surface of the first side column and the second side column.

[0041] In the embodiment, an air gap is left between the cover plate 201 and the first side column 211 and the second side column 212 of the magnetic core body 202, at this time, the cover plate can be preferably set as a nickel-zinc ferrite. The air gap is formed by padding a tape or an insulating material between the cover plate 201 and the first side column 211 and the second side column 212 of the magnetic core body 202. Of course, in other embodiments, an air gap can also be left in the cover plate 201, at this time, the cover plate is preferably set as a powder core material, and the powder core material has a distributed air gap inside. The powder core material can be selected as a material with low magnetic permeability (90u-9u), for example, a metal powder core, an alloy powder core, an iron powder core, etc. The position of the air gap of the magnetic element is not limited in the application. In addition, when the magnetic element is applied to a low frequency area (<3MHZ), the cover plate can be preferably set as a MnZn ferrite, which can effectively reduce the loss of the magnetic element. In the embodiment, the magnetic core body 202 is set as a nickel-zinc ferrite.

[0042] The pins of the magnetic element are located on the bottom surfaces of the first side column 211 and the second side column 212, and the upper surfaces of the first side column 211 and the second side column 212 are opposite to the bottom surfaces. The pins include first pins 221 located on the bottom surface of the first side column 211 and second pins 222 located on the bottom surface of the second side column 212. The winding 223 includes a first winding and a second winding, the first winding is wound on a first part of the middle column close to the first side column 211, and the second winding is wound on a second part of the middle column close to the second side column 212. The first end and the tail end of the first winding are directly spot-welded on the first pins, and the first end and the tail end of the second winding are directly spot-welded on the second pins. In the embodiment, the magnetic element is a transformer, the first winding is a primary winding, the second winding is a secondary winding, the first pins are primary pins, and the second pins are secondary pins.

[0043] In the application, at least two windings are wound on the middle column, and the number of the pins is not less than four. Specifically, in the embodiment, the number of the pins is six, including four primary pins and two secondary pins, and the number of the windings is three, including one primary winding and two secondary windings, and the turn ratio of the primary winding to the secondary winding is 1:2. It should be noted that the number of the pins and the number of the windings can be specifically set according to actual application, and are not limited herein.

[0044] In the embodiment, the bottom surfaces of the first side column 211 and the second side column 212 have recesses formed by etching, and the pins are formed by pasting metal sheets in the recesses. Of course, in other embodiments, the pins can also be formed by electroplating metal on the bottom surfaces of the first side column 211 and the second side column 212. The metal sheets and the electroplated metal can both be preferably silver material.

[0045] The magnetic element provided by the application adopts a nickel core ferrite as a magnetic core, and forms pins on the bottom of the magnetic core, and is a kind of magnetic element structure without framework, realizes the small size of the magnetic element, and reduces the cost. In addition, a plurality of pins can be set according to the need, and multi-way output is realized.

[0046] Figure 3a and 3b Fig. 2 shows a structure diagram of a magnetic element according to a second embodiment of the application. The difference between the magnetic core element of the embodiment and the first embodiment is that the magnetic core body 302 further includes a boss 321 located on the middle column 303, and other structures are the same, which will not be described herein.

[0047] The boss 321 separates the first winding 311 and the second winding 312 wound on the central post 303. The leakage inductance between the first winding 311 and the second winding 312 can be adjusted by changing the shape of the boss 321. The boss 321 is formed by extending onto one or more surfaces of the central post. Of course, the portion of the boss extending onto each surface of the central post does not exceed the upper, lower, and side surfaces of the first and second side posts. Here, the side surfaces of the first and second side posts do not include the surface connected to the central post, nor the surface opposite to the surface connected to the central post. The larger the volume of the boss 321, the greater the leakage inductance between the first winding 311 and the second winding 312. Specifically, in this embodiment, the boss 321 has a U-shaped structure, including a first portion located on the lower surface of the central pillar 303 away from the cover plate 301 and a second portion located on the side surface of the central pillar 303. The side surface of the central pillar 303 is connected to the lower surface. Here, the side surface of the central pillar 303 does not include the surface that connects to the first and second side pillars. Preferably, the side surface of the boss 321 is flush with the side surfaces of the first and second side pillars, and the bottom surface of the boss 321 is flush with the bottom surfaces of the first and second side pillars.

[0048] When the magnetic element is applied to certain circuit topologies, such as LLC circuits, the leakage inductance between the primary winding 311 and the secondary winding 312 can also be used as a resonant inductor to help achieve soft switching and reduce the number of magnetic elements in the circuit. Those skilled in the art can change the shape of the boss according to the actual application and circuit requirements to adjust the leakage inductance between the primary winding 311 and the secondary winding 312. No limitations are placed on the shape of the boss herein.

[0049] like Figure 4 As shown, the boss 322 is located on the lower surface of the central column 303 away from the cover plate 301. Preferably, the side surface of the boss 322 does not extend beyond the side surface of the central column 303; further, the side surface of the boss 322 is flush with the side surface of the central column 303. Figure 4 The leakage inductance between the primary and secondary windings in the structure is less than that between the primary and secondary windings in the structure shown in Figure 3.

[0050] like Figure 5As shown, the boss 323 is in a square ring structure, including a first part on the lower surface of the center column 303 away from the cover plate 301, a second part on the side surface of the center column 303 and a third part on the upper surface of the center column 303 close to the cover plate 301, preferably, the side surface of the boss 323 is flush with the side surface of the first and second edge columns, the bottom surface of the boss 323 is flush with the bottom surface of the first and second edge columns, and the upper surface of the boss 323 is flush with the upper surface of the first and second edge columns. It should be noted that in this structure, the leakage inductance of the magnetic element will be large, and the magnetic element will become a coupling inductor, which can be used for differential common mode integrated output inductance.

[0051] Figure 6 As shown, the cross-sectional view of the magnetic element according to the fifth embodiment of the present application. The difference between this embodiment and the magnetic core element of the second embodiment is that the number of turns of the winding is different, and the other structures are the same, which will not be repeated here.

[0052] In this embodiment, the number of turns of the first winding 611 and the second winding 612 is the same, that is, the turn ratio is 1:1, and the magnetic element becomes an inductor. When the magnetic element is a coupling inductor, a gap is left between the cover plate 601 and the first and second edge columns 604 and 605 of the magnetic core body to form an air gap of the magnetic element, and the coupling inductor can be used for double parallel. When the winding directions of the first winding 611 and the second winding 612 are the same, that is, the first winding and the second winding are both clockwise or counterclockwise, the magnetic element is a positive coupling inductor; when the winding directions of the first winding 611 and the second winding 612 are different, that is, the first winding is clockwise or counterclockwise, and the second winding is counterclockwise or clockwise, the magnetic element is a negative coupling inductor. The coupling coefficient of the coupling inductor can be adjusted by the size of the boss 603, and the larger the size of the boss 603, the larger the coupling coefficient of the coupling inductor.

[0053] When the magnetic element is used as a filter inductor, preferably, the magnetic element does not have an air gap. By setting the winding directions of the first winding 611 and the second winding 612 to be the same, the filter inductor can mainly suppress common mode signals, and also has a certain suppression ability for differential mode signals. And when the cover plate 601 is MnZn ferrite and the magnetic core body is NiZn ferrite, because MnZn ferrite is not insulating, it has suppression ability for low frequency loss, and the NiZn ferrite is an insulator, it has suppression ability for high frequency loss, so the filter inductor can suppress the insertion loss of high and low frequency bands, and improve the filtering ability of the filter inductor.

[0054] In accordance with the practices of the present invention, these embodiments have been described in relation to the above-described embodiments, which are intended to be illustrative only and not restrictive of the invention. Obviously, many modifications and variations of this invention can be effected without departing from the scope of the novel concept of the disclosure. No limitation with respect to the specific implementation techniques and applications presented thereby should be inferred into the scope of the invention, as understood by those skilled in the art. The specification and drawings should be regarded as illustrative only and in no way limiting of the scope of the invention as defined by the appended claims and equivalents thereof.

Claims

1. A magnetic element, characterized in that, Including the cover plate and the magnetic core body, The magnetic core body includes a first side post and a second side post, and a middle post connected between the first side post and the second side post, with a winding wound on the middle post; The cover plate is fixed to the upper surface of the first and second side posts; The winding includes a first winding and a second winding. The first winding is wound on a first portion of the central post near the first side post, and the second winding is wound on a second portion of the central post near the second side post. The magnetic core body also includes a boss located on the central post to separate the first winding and the second winding wound on the central post. The boss includes a first portion located on the lower surface of the central post away from the cover plate. By changing the shape of the boss, the leakage inductance between the first winding and the second winding is adjusted. An air gap is left in the cover plate. The cover plate is set to have a powder core material with distributed air gaps inside and is a low permeability material. The magnetic core body is set to nickel-zinc ferrite.

2. The magnetic element according to claim 1, wherein, The magnetic core body is I-shaped.

3. The magnetic element according to claim 1, wherein, The boss is formed by extending from one or more surfaces of the central column.

4. The magnetic element according to claim 1, wherein, The boss is located on the lower surface of the central column away from the cover plate.

5. The magnetic element according to claim 1, wherein, The side surface of the boss does not extend beyond the side surface of the central column, and the side surface of the central column is connected to the lower surface.

6. The magnetic element according to claim 1, wherein, The boss has a U-shaped structure and also includes a second part located on the side surface of the central column, the side surface of the central column being connected to the lower surface.

7. The magnetic element according to claim 1, wherein, The boss has a square ring structure and also includes a second part located on the side surface of the central column and a third part located on the upper surface of the central column near the cover plate.

8. The magnetic element according to claim 6 or 7, wherein, The side surface of the boss does not extend beyond the side surfaces of the first and second side posts.

9. The magnetic element according to claim 1, wherein, The pins of the magnetic element are located on the bottom surfaces of the first and second side posts, and the upper surfaces of the first and second side posts are opposite to the bottom surfaces.

10. The magnetic element according to claim 9, wherein, The pins include a first type of pin and a second type of pin, with the first type of pin located on the bottom surface of the first side post and the second type of pin located on the bottom surface of the second side post.

11. The magnetic element according to claim 10, wherein, The start and end points of the first winding are soldered to the corresponding first type of pins, and the start and end points of the second winding are soldered to the corresponding second type of pins.

12. The magnetic element according to claim 9, wherein, The number of pins shall be no less than four.

13. The magnetic element according to claim 1, wherein, At least two windings are wound on the central column.

14. The magnetic element according to claim 1, wherein when the number of turns of the first winding and the second winding are different, the magnetic element is a transformer.

15. The magnetic element according to claim 1, wherein when the number of turns of the first winding and the second winding are the same, the magnetic element is an inductor.

16. The magnetic element according to claim 9, wherein, The pins are formed by electroplating on the bottom surfaces of the first and second side posts.

17. The magnetic element according to claim 9, wherein, The bottom surfaces of the first and second side pillars have etched recesses.

18. The magnetic element according to claim 17, wherein, The pin is formed by attaching a metal sheet to the recess.

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