WO2022133662A1

WO2022133662A1 - Planar wire-wound transformer and manufacturing method therefor

Info

Publication number: WO2022133662A1
Application number: PCT/CN2020/138061
Authority: WO
Inventors: 李园龙; 陈嘉兆
Original assignee: 深圳顺络电子股份有限公司
Priority date: 2020-12-21
Filing date: 2020-12-21
Publication date: 2022-06-30

Abstract

A planar wire-wound transformer and a manufacturing method therefor. Coils, and windings in a PCB substrate are used to jointly form all windings of the planar wire-wound transformer. When the number of turns of all the windings is unchanged, the number of layers of the PCB substrate is reduced, thereby reducing the thickness of the PCB substrate. Therefore, the design and manufacturing difficulties of the PCB substrate are reduced, thereby reducing the manufacturing difficulty of the planar wire-wound transformer.

Description

A kind of plane winding transformer and its manufacturing method

technical field

The present application relates to the technical field of transformers, and in particular to a planar winding transformer and a manufacturing method thereof.

Background technique

Transformers are often used in electronic products. The traditional transformer is to wind the coil on the existing skeleton and assemble it with the magnetic core to form a transformer. However, this kind of transformer is large in size and has poor coupling and heat dissipation. , The winding structure is complex, the consistency of the winding is difficult to guarantee, and it cannot adapt to the development trend of the gradual miniaturization, thinning, high power and high efficiency of electronic products.

Planar transformer is a kind of transformer with high frequency, low profile, small height and high operating frequency, so it can adapt to the development trend of electronic products gradually miniaturized, light and thin, high power and high efficiency.

technical problem

Existing planar transformers are assembled from a PCB (printed circuit board) substrate and a magnetic core. The PCB substrate has multiple layers of printed circuits to form windings, but too many winding turns will make the design and manufacture of the PCB substrate difficult. and inconvenience, thus making the fabrication of planar transformers more difficult.

technical solutions

The present application discloses and provides a planar winding transformer, comprising: a magnetic core; a PCB substrate disposed on the magnetic core, in which windings are printed and pad through holes are opened; The pins pass through the through holes of the pads; the coils are arranged on the PCB substrate and are independent of the PCB substrate, and the windings of the coils and the PCB substrate serve as all the windings of the planar winding transformer; The foam is arranged between the magnetic core and the coil, and the foam is located between the magnetic core and the coil.

The present application discloses another manufacturing method of a planar wound transformer, which includes: winding a coil, and printing the winding in a PCB substrate, the coil and the PCB substrate are independent of each other; passing the pins through the pad through holes opened on the PCB substrate , and soldered on the PCB substrate; the coil is soldered on the PCB substrate through the designated or specific part of the pins, so that the coil and the windings of the PCB substrate are connected through the pins to form the planar winding transformer All windings; the PCB substrate welded with coils and pins is assembled with the magnetic core, foam and the transformer shell to make the plane winding transformer.

beneficial effect

In this application, the coils and the windings in the PCB substrate are used to form all the windings of the planar winding transformer, that is, some of the windings are printed in the PCB substrate, and the other part of the windings are on the PCB substrate and are independent from each other. Under the same condition, the number of layers of the PCB is reduced, thereby reducing the thickness of the PCB, thus reducing the design and manufacturing difficulty of the PCB substrate, thereby reducing the manufacturing difficulty of the planar wire-wound transformer.

Description of drawings

1 is a schematic structural diagram of a planar wound transformer according to an embodiment of the present application;

Fig. 2 is the exploded view of the plane wound transformer of the embodiment of the present application;

3 is a schematic structural diagram of a PCB substrate of a planar wire wound transformer according to an embodiment of the present application;

4 is a schematic diagram of an assembly of a PCB substrate and a coil of a planar wire wound transformer according to an embodiment of the present application;

5 is a bottom view of the PCB substrate and the coil of the planar wire wound transformer according to the embodiment of the present application after being assembled;

6 is a schematic structural diagram of a magnetic core and a center column of the magnetic core of the planar wound transformer according to an embodiment of the present application;

FIG. 7 is a flowchart of a manufacturing method of a planar wound transformer according to an embodiment of the present application.

Embodiments of the present invention

The primary purpose of the present invention is to form all the windings of the planar winding transformer by using the coils and the windings in the PCB substrate, that is, part of the windings are printed in the PCB substrate, and the other part of the windings are on the PCB substrate and are independent from the PCB substrate. Under the condition that the number of turns of all windings remains unchanged, the number of layers of the PCB is reduced, thereby reducing the thickness of the PCB, thus reducing the design and manufacturing difficulty of the PCB substrate, thereby reducing the manufacturing difficulty of the planar winding transformer.

The technical solutions of the various exemplary embodiments provided by the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. In the case of no conflict, the following various embodiments and their technical features can be combined with each other.

Directional terms mentioned in the present invention, such as up, down, top, bottom, front, back, left, right, inner, outer, side, surrounding, central, horizontal, lateral, vertical, longitudinal, axial, radial, most The upper layer or the lowermost layer, etc., only refer to the direction of the drawings. Therefore, the directional terms used are for describing and understanding the present invention, not for limiting the present invention.

Please refer to FIG. 1 and FIG. 2 , a planar wire wound transformer provided in an embodiment of the application includes: a magnetic core 1, a PCB substrate 2, pins 4, a coil 3 and a foam 7; the PCB substrate 2 is arranged on the magnetic core 1, the winding is printed in it, and the pad through hole 24 is opened; the pin 4 is arranged on the PCB substrate 2, and the pin 4 passes through the pad through hole 24; the coil 3 is arranged on the PCB substrate 2, and is connected with the PCB substrate 2. The PCB substrate 2 is independent of each other, and the windings of the coil and the PCB substrate serve as all the windings of the planar winding transformer; the foam 7 is arranged between the magnetic core 1 and the coil 3 .

In this embodiment, the first winding and the coil together form all the windings of the planar winding transformer, that is, a part of the windings of all the windings are printed in the PCB substrate 2, and the other part of the windings (coils) are on the PCB substrate 2 and are connected with the PCB substrate 2. Independent of each other, under the condition that the number of turns of all the windings of the planar winding transformer remains unchanged, the number of layers of the PCB is reduced, thereby reducing the thickness of the PCB, thus reducing the design and manufacturing difficulty of the PCB substrate 2, thereby reducing the plane. The difficulty of making a wound transformer.

The foam 7 itself has a certain thickness and elasticity. The PCB substrate 2 and the coil 3 are fixed by the extrusion of the foam 7 between the coil 3 and the magnetic core 1, and the vibration of the planar winding transformer during operation can be reduced to ensure Capacitance consistency.

In addition, the planar wound transformer made of the above components has the advantages of light weight, high efficiency, low loss and high consistency.

Referring to FIG. 2, in one embodiment, the planar wound transformer further includes: a spacer 6 disposed between the coil 3 and the magnetic core 1 and/or disposed between the PCB substrate 2 and the coil 3, the spacer 6 insulating .

In this embodiment, a spacer 6 is arranged between the coil 3 and the magnetic core 1, and the spacer 6 is arranged between the coil 3 and the magnetic core 1, which can increase the withstand voltage requirement between the magnetic core 1 and the coil 3, so that the The withstand voltage performance of the planar winding transformer is improved, and the eddy current loss during operation of the planar winding transformer can be reduced.

In other embodiments, a spacer 6 is provided between the PCB substrate 2 and the coil 3, and a spacer 6 is provided between the PCB substrate 2 and the coil 3. The thickness of the spacer 6 is different, which can make the leakage inductance of the planar winding transformer. Therefore, by adjusting the thickness of the spacer 6, the leakage inductance of the planar wound transformer can be adjusted.

In other embodiments, spacers 6 are provided between the coil 3 and the magnetic core 1, and between the PCB substrate 2 and the coil 3. The spacer 6 provided between the coil 3 and the magnetic core 1 increases the number of the magnetic core 1 and the magnetic core 1. The withstand voltage requirement between the coils 3 improves the withstand voltage performance of the planar wound transformer, and can reduce the eddy current loss during operation of the planar wound transformer. The gasket 6 set between the PCB substrate 2 and the coil 3 can be adjusted by adjusting The thickness of the gasket 6 can adjust the leakage inductance of the planar winding transformer. The thicker the gasket 6, the smaller the leakage inductance.

Referring to FIG. 5 , in one embodiment, the magnetic core 1 includes an upper magnetic core 12 , a lower magnetic core 11 and a central column 111 of the magnetic core 1 . The central column 111 of the magnetic core 1 is disposed on the lower magnetic core 11 and is located in the upper magnetic core 12 and the lower magnetic core 11, please refer to FIG. 2, the PCB substrate 2 is arranged between the upper magnetic core 12 and the lower magnetic core 11, the foam 7 is arranged between the upper magnetic core 12 and the PCB substrate 2, the gasket 6 It is arranged between the upper magnetic core 12 and the coil 3 and/or between the PCB substrate 2 and the lower magnetic core 11 .

In one embodiment, the upper magnetic core 12 is of an "I" shape or an "E" shape, and the lower magnetic core 11 and the central column 111 are of an "E" shape as a whole.

Referring to FIG. 5 , in this embodiment, the upper magnetic core 12 is of “I” type, the upper magnetic core 12 and the lower magnetic core 11 commonly form a hollow quadrangular prism, one end of the central column 111 is arranged on the lower magnetic core 11 , and the other One end is in contact with the upper magnetic core 12 , and the upper magnetic core 12 , the lower magnetic core 11 and the central column 111 form an EI-type magnetic core as a whole.

Referring to FIG. 5 , in this embodiment, the shape of the central column 111 is a cylindrical shape, and in other embodiments, the shape of the central column 111 may also be a polygonal column or other shapes.

In other embodiments, the upper magnetic core 12 may also be E-shaped, the lower magnetic core 11 and the central column 111 may be of an “E” shape as a whole, and the upper magnetic core 12 , the lower magnetic core 11 and the central column 111 may form an EE-shaped magnetic core as a whole .

Referring to FIG. 2 , in this embodiment, the spacer 6 is disposed between the lower magnetic core 11 and the PCB substrate 2 .

Please refer to FIG. 2 and FIG. 3 , in one embodiment, there are two coils 3 , which are respectively attached to the front and back sides of the PCB substrate, and are the first coil 31 and the second coil 32 respectively. 31 is arranged between the PCB substrate 2 and the upper magnetic core 12, the foam 7 is arranged between the upper magnetic core 12 and the first coil 31, the second coil 32 is arranged between the PCB substrate 2 and the lower magnetic core 11, and the gasket 6 is disposed between the PCB substrate 2 and the first coil 31 and/or between the lower magnetic core 11 and the second coil 32 .

In this embodiment, the gasket 6 is disposed between the lower magnetic core 11 and the second coil 32, which can effectively enhance the withstand voltage performance of the planar wound transformer and reduce the eddy current loss during operation.

In other embodiments, the gasket 6 can also be arranged between the upper magnetic core 12 and the first coil 31, which can effectively enhance the withstand voltage performance of the planar wound transformer and reduce the eddy current loss during operation.

In other embodiments, the spacer 6 is disposed between the PCB substrate 2 and the first coil 31 , and the leakage inductance of the planar wound transformer can be adjusted by adjusting the thickness of the spacer 6 .

In other embodiments, the gasket 6 is disposed between the PCB substrate 2 and the second coil 32 , and the leakage inductance of the planar wound transformer can be adjusted by adjusting the thickness of the gasket 6 .

In other embodiments, spacers 6 are arranged between the upper magnetic core 12 and the first coil 31 and between the lower magnetic core 11 and the second coil 32, so as to enhance the withstand voltage performance of the planar wound transformer and reduce the operation The eddy current loss at the time of adjusting the leakage inductance of the planar wound transformer.

In one embodiment, the PCB substrate 2 includes: at least two layers of printed circuit boards and a dielectric layer disposed between adjacent printed circuit boards.

Different thicknesses of the dielectric layer can make the plane wound transformer have different leakage inductance and capacitance. The thicker the dielectric layer, the smaller the capacitance and leakage inductance. Therefore, the plane with different leakage inductance and capacitance can be made by adjusting the thickness of the dielectric layer. Winding transformer; in other embodiments, an insulating layer can also be added outside the planar wound transformer to adjust the leakage inductance and capacitance of the planar wound transformer, the insulating layer is FR4 epoxy board, the thicker the insulating layer, the leakage inductance and capacitance smaller.

Referring to FIG. 6 , in one embodiment, the printed circuit board includes: a board body 21 , the board body 21 is provided with an internal wiring hole 25 , a central column via hole 23 and a groove 26 , and the pad through hole 24 is opened in the board body 21, the central column via hole 23 is used for the central column 111 of the magnetic core 1 to pass through; the inner coil 22 arranged on the plate body 21; the conductive layer arranged on the inner wall of the inner wire hole 25, the conductive layer is used to pass The inner coil 22 of the winding hole is connected to form a winding.

In this embodiment, a circuit structure composed of multiple layers of internal coils 22 is printed in the printed circuit board of each layer, and the conductive layer on the inner wall of the internal wiring hole 25 connects the inner wall of the wiring hole in one layer of the printed circuit board. The coils 22 are connected to form a winding.

Referring to FIGS. 1 and 2 , in one embodiment, the planar wound transformer further includes: a transformer casing 5 inserted into the groove 26 to fix the plate body 21 , thereby increasing the safety distance of the planar wound transformer.

The transformer casing 5 also acts as a retaining wall to increase the safety distance, prevent the safety distance of external objects when the plane winding transformer is working, and meet the safety requirements.

In one embodiment, the material of the gasket 6 is polyimide.

Polyimide has good insulation performance and low cost, and can be used as an insulating material. When placed between the lower magnetic core 11 and the second coil 32, it can effectively enhance the withstand voltage performance of the planar winding transformer and reduce the operating time. When placed between the upper magnetic core 12 and the first coil 31, the leakage inductance of the planar winding transformer can be well adjusted by adjusting the thickness of the gasket 6.

In one embodiment, the wire material of the coil 3 is an insulated self-adhesive wire of the FIW series. The withstand voltage of the coil of this wire to the magnetic core is greater than or equal to 1000Vac. Insulated self-adhesive wire can be single-strand or multi-strand. In other embodiments, coils of other wire materials with a withstand voltage greater than or equal to 1000 Vac may be used.

In one embodiment, the winding method of the coil 3 is α winding.

In one embodiment, the coil 3 has two lead ends.

Referring to FIG. 7 , a method for manufacturing a planar wire wound transformer provided in an embodiment of the present application includes: S1, winding a coil, and printing windings in a PCB substrate, and the coil and the PCB substrate are independent of each other; S2, connecting the pins Pass through the pad through holes opened on the PCB substrate, and solder on the PCB substrate; S3, solder the coil on the PCB substrate through the specific or designated pins, so that the coil and the windings of the PCB substrate are connected by pins to All the windings of the plane winding transformer are formed; S4, the PCB substrate welded with the coil and the pins is assembled with the magnetic core, the foam and the transformer shell to make the plane winding transformer.

In step S4, after the PCB substrate welded with the coils and pins is assembled with the magnetic core, the foam and the transformer shell, the assembled parts are baked and fixed by epoxy resin glue. , Assembled and disassembled separately, not fixed with the PCB substrate by glue.

The planar wound transformer produced by the above method, because the coils and the windings printed in the PCB substrate are used to form all the windings of the planar wound transformer, that is, a part of the windings of all the windings are printed in the PCB substrate 2, and the other part of the windings (coils) On the PCB substrate 2 and independent of the PCB substrate 2, under the condition that the number of turns of all windings remains unchanged, the number of layers of the PCB substrate is reduced, thereby reducing the number of layers of the PCB substrate, thus reducing the design and production of the PCB substrate. Difficulty, thereby reducing the manufacturing difficulty of the plane wound transformer.

In step S2, in the coil winding process, the surface of the used jig is coated with Teflon, which can well prevent damage to the enameled film of the insulating self-adhesive wire during the coil manufacturing process. And the production of the coil can be realized by using a semi-automatic CNC winding machine or a fully automatic machine, which improves the consistency and qualification rate of the product. The above-mentioned example coils are wound into a single coil by the α-winding method using a single-strand insulated self-adhesive wire.

In one embodiment, after assembling the PCB substrate on which the coils and pins are welded, the magnetic core, the foam and the transformer casing, the assembled parts are fixed by using epoxy resin glue and baking.

In one embodiment, during the winding process of the coil, the coil needs to be heated to melt the enameled film of the insulating self-adhesive wire.

While the invention has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art upon a reading and understanding of this specification and the accompanying drawings. The present invention includes all such modifications and variations and is limited only by the scope of the appended claims. In particular with regard to the various functions performed by the above-described components, the terms used to describe such components are intended to correspond to any component that performs the specified function of the component (eg, which is functionally equivalent) (eg, which is functionally equivalent) (unless otherwise indicated) , even if not structurally equivalent to the disclosed structures that perform the functions of the exemplary implementations of the specification shown herein. Furthermore, although a particular feature of this specification has been disclosed with respect to only one of several implementations, such feature may be combined with one or more of the other implementations as may be desirable and advantageous for a given or particular application Other feature combinations. Moreover, to the extent that the terms "comprising," "having," "containing," or variations thereof are used in the detailed description or the claims, such terms are intended to include in a manner similar to the term "comprising." Further, it should be understood that "a plurality" referred to herein refers to two or more. For the steps mentioned in this document, the numerical suffixes are only used to express the embodiments clearly and to facilitate understanding, and do not completely represent the sequence of execution of the steps, and should be considered in terms of the sequence of logical relationships.

The above descriptions are only the embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, such as the interaction of technical features between the embodiments Combination, or direct or indirect application in other related technical fields, are also included in the scope of patent protection of the present invention.

Claims

A plane wound transformer, comprising:

magnetic core;

The PCB substrate arranged on the magnetic core is printed with windings and has through-holes for pads;

pins arranged on the PCB substrate, the pins pass through the pad through holes;

a coil arranged on the PCB substrate and independent of the PCB substrate, and the windings of the coil and the PCB substrate serve as all the windings of the planar winding transformer;

The foam is arranged between the magnetic core and the coil, and the foam is located between the magnetic core and the coil.
The planar wound transformer of claim 1, further comprising:

A spacer is provided between the coil and the magnetic core and/or between the PCB substrate and the coil, and the spacer is insulated.
The planar wound transformer of claim 2, wherein,

The magnetic core includes an upper magnetic core, a lower magnetic core and a magnetic core middle column, the magnetic core middle column is arranged on the lower magnetic core and is located between the upper magnetic core and the lower magnetic core, the The PCB substrate is arranged between the upper magnetic core and the lower magnetic core, the foam is arranged between the upper magnetic core and the PCB substrate, and the gasket is arranged between the lower magnetic core and the lower magnetic core and/or the coil is arranged between the PCB substrate and the coil.
The planar wound transformer of claim 3, wherein,

The coils are provided with two coils, namely a first coil and a second coil, the first coil is provided between the PCB substrate and the upper magnetic core, and the foam is provided between the upper magnetic core and the upper magnetic core. Between the first coils, the second coil is arranged between the PCB substrate and the lower magnetic core, and the gasket is arranged between the PCB substrate and the first coil and/or at the between the lower magnetic core and the second coil.
The planar wound transformer of claim 1, wherein,

The PCB substrate includes:

At least two layers of printed circuit boards and a dielectric layer disposed between adjacent printed circuit boards.
The planar wire wound transformer of claim 5, wherein the printed circuit board comprises:

The board body, the board body is provided with an internal wire hole, a central column via hole and a groove, the pad through hole is opened on the board body, and the central column via hole is used for the central column of the magnetic core to pass through. Pass;

an internal coil arranged on the plate body;

A conductive layer arranged on the inner wall of the inner wire-passing hole, the conductive layer is used to connect the inner coil passing through the wire-winding hole into a winding.
The planar wound transformer of claim 6, wherein,

The plane wound transformer further includes: a transformer casing inserted into the groove to increase the safety distance.
The planar wound transformer of claim 2, wherein,

The material of the gasket is polyimide.
The planar wound transformer of claim 1, wherein,

The wire of the coil is FIW series insulated self-adhesive wire;

The winding method of the coil is α winding.
The planar wound transformer of claim 1, wherein,

The coil has two lead ends.
The planar wound transformer of claim 3, wherein,

The upper magnetic core is in an "I" shape, and the lower magnetic core and the middle column are in an "E" shape as a whole.
The planar wound transformer of claim 3, wherein,

The upper magnetic core is in an "E" shape, and the lower magnetic core and the middle column are in an "E" shape as a whole.
The planar wound transformer of claim 3, wherein,

The shape of the central column is cylindrical or polygonal.
The planar wound transformer of claim 9, wherein,

The coil is an insulated self-adhesive wire with a withstand voltage greater than or equal to 1000Vac.
The planar wound transformer of claim 1, wherein,

The coil is provided with one or at least two strands.
The planar wound transformer of claim 15, wherein,

The coils of at least two strands are arranged in series or in parallel.
A manufacturing method of a plane wound transformer, comprising:

Winding the coil and printing the windings in the PCB substrate, the coil and the PCB substrate are independent of each other;

Pass the pins through the pad through holes opened on the PCB substrate, and solder them on the PCB substrate;

Soldering the coil on the position where the PCB substrate passes through the specific or designated pins, so that the coil and the windings of the PCB substrate are connected through the pins to form all the windings of the planar winding transformer;

The flat winding transformer is made by assembling the PCB substrate welded with the coil and the pins, the magnetic core, the foam and the transformer casing.
The manufacturing method of the planar wound transformer according to claim 17, wherein, comprising:

After the PCB substrate welded with the coils and pins is assembled with the magnetic core, the foam and the transformer shell, the assembled parts are fixed by epoxy resin glue and baked.
The manufacturing method of the planar wound transformer according to claim 17, wherein, comprising:

The winding of the coil includes: winding the insulating self-adhesive wire into a coil by using an α-winding method.
The manufacturing method of a planar wound transformer according to claim 18, comprising:

The winding coil also includes:

The coil is heated to melt the enameled film of the insulating self-adhesive wire.