CN218351250U

CN218351250U - Flat transformer and electronic equipment

Info

Publication number: CN218351250U
Application number: CN202220471588.9U
Authority: CN
Inventors: 任文; 廖胜峰
Original assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd
Current assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd
Priority date: 2022-03-03
Filing date: 2022-03-03
Publication date: 2023-01-20
Anticipated expiration: 2032-03-03

Abstract

The application discloses a flat-panel transformer and electronic equipment, including the winding of a multilayer circuit board and two kinds of attributes. The windings of both attributes are provided on the circuit board for forming a path for the current. The circuit board comprises a wire loading part, a first wire outlet part and a second wire outlet part, wherein the first wire outlet part and the second wire outlet part are connected with the wire loading part, the first wire outlet part can be provided with a plurality of first electric connecting pieces, and the second wire outlet part can be provided with a plurality of second electric connecting pieces. The windings with two attributes are manufactured on the wire loading parts, wherein one attribute winding is connected with the first electric connecting piece through the first wire outlet part, and the other attribute winding is connected with the second electric connecting piece through the second wire outlet part. And combining manufacturing tolerance, wherein the shortest creepage distance between the outermost winding and the second electric connection part is more than or equal to 7.5mm. The design can improve the security performance of the flat-plate transformer, avoid the second to connect the electric component and receive the influence of the winding, make the operating condition of the flat-plate transformer more stable.

Description

Flat-plate transformer and electronic equipment

Technical Field

The application relates to the technical field of transformers, in particular to a flat-plate transformer and electronic equipment.

Background

With the development of transformer technology, flat transformers are widely used in different electronic devices. The biggest difference of the flat-plate transformer compared with the traditional transformer is that the flat-plate transformer is provided with an iron core and a coil winding. Planar transformers are typically made of high frequency power ferrite materials and have low core losses at high frequencies. The winding is generally formed by winding a plurality of layers of printed circuit boards, and the winding or copper sheets are overlapped on the planar high-frequency iron core to form a magnetic loop of the transformer, so that the flat transformer is more flattened.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a flat-plate transformer, through setting up the first outgoing line portion that has first electrical connection spare and the second outgoing line portion that has the second electrical connection spare, and the shortest creepage distance between outermost winding and the second electrical connection spare is more than or equal to 7.5mm, has improved flat-plate transformer's security performance, makes flat-plate transformer's operating condition more stable.

The embodiment of the application provides a planar transformer, includes:

the multilayer circuit board comprises a wire loading part, a first wire outlet part and a second wire outlet part, wherein the first wire outlet part and the second wire outlet part are connected with the wire loading part, the first wire outlet part is provided with a plurality of first electric connecting pieces, and the second wire outlet part is provided with a plurality of second electric connecting pieces;

the windings with two attributes are manufactured on the wire loading part, one of the windings with two attributes is connected with the first electric connecting piece through the first wire outlet part, the other of the windings with two attributes is connected with the second electric connecting piece through the second wire outlet part, and the windings with two attributes are respectively a primary winding and a secondary winding;

and in combination with manufacturing tolerance, the shortest creepage distance between the outermost winding and the second electric connecting piece is more than or equal to 7.5mm.

The beneficial effects of the embodiment of the application are as follows: the minimum creepage distance between the outermost winding and the second electrical part is more than or equal to 7.5mm by arranging the first creepage part with the first electrical part and arranging the second creepage distance with the second electrical part, wherein the creepage distance refers to the distance between the winding connected with the first electrical part and the second electrical part to realize electrical connection along the surface of the circuit board, the safety performance of the flat-plate transformer is improved by keeping the second electrical part away from the electrified region of the winding, the influence of the winding on the second electrical part is avoided, the working state of the flat-plate transformer can be more stable, even if an error is generated in production, the minimum creepage distance of 7.5mm is enough to ensure the safety performance of the flat-plate transformer.

In some embodiments, any connection position between the first wire-out portion and the wire-carrying portion is a first connection position, any connection position between the second wire-out portion and the wire-carrying portion is a second connection position, a plurality of wires are arranged at different first connection positions and different second connection positions, and an extending direction of any one wire forms an included angle with a length direction of the second wire-out portion.

Based on the above embodiment, the extending direction of the connecting line and the length direction of the second outgoing line part form an included angle, that is, the second outgoing line part is obliquely arranged relative to the line carrying part, so that the overall length size of the circuit board can be reduced.

In some embodiments, an extending direction of at least one of the connecting lines is perpendicular to a length direction of the second outgoing line portion.

Based on the embodiment, the extending direction of the connecting line is perpendicular to the length direction of the second outgoing line part, so that the length scale of the circuit board in the extending direction of the connecting line is reduced to the greatest extent on the premise of ensuring the working performance of the circuit board, the area of the circuit board is reduced, the production cost of the flat-plate transformer is further reduced, and the quantitative production of the flat-plate transformer is facilitated.

In some embodiments, the second wire outlet portion includes:

the wire outlet sub-part is arranged in a substantially rectangular plate and is provided with a plurality of second electric connecting pieces;

the connecting sub-portion is used for connecting the wire loading portion and the wire outgoing sub-portion, and the second connecting position is located on the connecting sub-portion.

Based on the above embodiment, the second wire outlet portion is arranged to comprise the wire outlet sub-portion and the connecting sub-portion, the wire outlet sub-portion is connected with the wire loading portion through the connecting sub-portion, and the plurality of second electric connecting pieces are arranged on the wire outlet sub-portion, so that the distance between the second electric connecting pieces and a winding connected with the first electric connecting pieces is increased, and the safe working performance of the flat-plate transformer is improved.

In some embodiments, the extending direction of the wide side of the line outgoing sub-portion far away from the line loading portion avoids the line loading portion, and the extending direction of the wide side of the line outgoing sub-portion close to the line loading portion passes through the line loading portion.

Based on the embodiment, one end of the wire outgoing sub-portion extends towards the direction away from the wire loading portion, so that the circuit boards are Z-shaped, and a plurality of Z-shaped circuit boards can be spliced in a staggered mode up and down, the number of typesetting of the circuit boards in a unit area of the board is increased, the utilization rate of the board is improved, the generation of waste boards is reduced, the environment is protected, and meanwhile, the production cost of the flat-plate transformer is further reduced.

In some embodiments, the second electrical components are arranged along the width direction of the wire outlet sub-portion, the wire outlet sub-portion has two wide sides, and the second electrical components are arranged closer to one of the two wide sides far away from the wire loading portion; or

The second electric connecting pieces are arranged along the length direction of the wire outgoing sub-portion, the wire outgoing sub-portion is provided with two long edges, and the second electric connecting pieces are arranged close to the long edges, far away from the wire loading portion, of the two long edges.

Based on the above embodiment, the plurality of second electrical components are designed to be arranged along the width direction of the outgoing line sub-portion and are arranged closer to the wide side far away from the line-carrying portion in the two wide sides, so that the length direction of the outgoing line sub-portion can be shrunk to be smaller; the second electric connecting pieces are designed to be arranged along the length direction of the outgoing line sub-portion and are arranged closer to the long edge far away from the line carrying portion in the two long edges, so that the size of the outgoing line sub-portion in the width direction can be reduced to be smaller. Meanwhile, the flat-plate transformer with the plurality of second electric connecting pieces arranged in the direction more meeting the requirement can be selected according to actual use requirements and production requirements.

In some embodiments, the two wide sides of the line outgoing sub-portion pass through the line loading portion, the line outgoing sub-portion has a first long side and a second long side which are parallel to each other, the first long side is closer to the line loading portion than the second long side, the connecting portion is connected to any end of the first long side, and the first long side, the connecting portion and the line loading portion together form a spacing groove.

Based on the above embodiment, the first long edge, the connecting sub-portion and the wire carrying portion are surrounded to form the spacing groove, so that the spacing distance between the winding electrically connected with the first electric connecting part and the second electric connecting part along the surface of the circuit board is increased, and the creepage distance required by the winding is ensured.

In some embodiments, a plurality of the second electrical components are arranged along the length direction of the line outgoing sub-portion, and in the width direction of the line outgoing sub-portion, the projection of the second electrical components on the first long side falls into the spacing groove.

Based on above-mentioned embodiment, connect the projection design of piece on first long limit with the second and for falling into the space groove, make the second connect the setting of keeping away from the winding of piece bigger degree, not only do benefit to the panel transformer miniaturization, still promoted the security performance and the stability of panel transformer.

In some of these embodiments, further comprising;

a magnetic core, the circuit board set in the magnetic core.

Based on above-mentioned embodiment, set up planar transformer to still including the magnetic core, the magnetic core can increase the magnetic permeability, reduces the eddy current loss, anti-jamming action in addition.

In a second aspect, an embodiment of the present application provides an electronic device, which includes a housing and the planar transformer described in any one of the above, where the planar transformer is disposed in the housing.

According to the flat-plate transformer and the electronic equipment in the embodiment of the application, through the arrangement of the first outgoing line part with the first electric connecting piece and the second outgoing line part with the second electric connecting piece, the shortest creepage distance between the winding connected with the first electric connecting piece and the second electric connecting piece is larger than or equal to 7.5mm, wherein the creepage distance refers to the distance between the winding connected with the first electric connecting piece and the second electric connecting piece along the surface of the circuit board, the creepage distance refers to the distance between the winding connected with the first electric connecting piece and the second electric connecting piece, the creepage distance is arranged by keeping away from the electrified region of the winding, the safety performance of the flat-plate transformer is improved, the second electric connecting piece is prevented from being influenced by the winding, the working state of the flat-plate transformer can be more stable, even errors are generated in production, the minimum creepage distance of 7.5mm is also enough to guarantee the safety performance of the flat-plate transformer, and the safety performance and the stability performance of the electronic equipment are further improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

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

fig. 2 is a schematic structural diagram of a planar transformer according to another embodiment of the present application;

fig. 3 is a schematic structural diagram of a planar transformer according to another embodiment of the present application;

fig. 4 is a schematic structural diagram of a planar transformer according to yet another embodiment of the present application;

fig. 5 is a schematic layout diagram of a planar transformer according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of a planar transformer according to yet another embodiment of the present application;

fig. 7 is a schematic structural diagram of a planar transformer according to yet another embodiment of the present application.

Reference numerals are as follows: 100. a planar transformer; 110. a circuit board; 111. a wire-carrying portion; 112. a first wire outlet portion; 113. a second wire outlet portion; a. connecting wires; b. a length direction of the second outgoing part; 1131. a wire outlet sub-part; 1132. a connector section; c. a first long side; d. a second long side; 114. a first electric connection piece; 115. a second electric connection piece; 120. a winding; 130. a spacing groove; 140. a magnetic core.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

With the development of transformer technology, planar transformers are widely used in different electronic devices. The biggest difference of the flat-plate transformer compared with the traditional transformer is that the flat-plate transformer is provided with an iron core and a coil winding. Planar transformers are typically made of high frequency power ferrite materials and have low core losses at high frequencies. The winding is generally formed by winding a plurality of layers of printed circuit boards, and the winding or copper sheets are overlapped on the planar high-frequency iron core to form a magnetic loop of the transformer, so that the flat-plate transformer is more flat. In the related art, the electrical connection part for connecting the primary winding of the flat-plate transformer is closer to the secondary winding, or the electrical connection part for connecting the secondary winding of the flat-plate transformer is closer to the primary winding, so that the safety performance of the flat-plate transformer is lower. The embodiment of the application provides a flat-plate transformer and electronic equipment, and aims to improve the safety performance of the flat-plate transformer.

In a first aspect, referring to fig. 1, an embodiment of the present application provides a planar transformer 100, where the planar transformer 100 may include a multi-layer circuit board 110 and windings 120 with two properties. The windings 120 of both attributes are disposed on the circuit board 110, and are used for forming a current path and generating an induced electromotive force by electromagnetic induction.

Referring to fig. 1, the circuit board 110 may include a wire loading portion 111, a first wire-out portion 112 and a second wire-out portion 113, wherein the first wire-out portion 112 and the second wire-out portion 113 are connected to the wire loading portion 111, the first wire-out portion 112 may be provided with a plurality of first electrical components 114, and the second wire-out portion 113 may be provided with a plurality of second electrical components 115. The windings 120 with two attributes are manufactured on the wire loading part 111, wherein the winding 120 with one attribute is connected with the first electric connecting piece 114 through the first wire outlet part 112, the winding 120 with the other attribute is connected with the second electric connecting piece 115 through the second wire outlet part 113, and the windings 120 with two attributes are respectively a primary winding and a secondary winding. And in combination with manufacturing tolerance, the shortest creepage distance between the outermost winding 120 and the second electric connecting part 115 is more than or equal to 7.5mm.

In the embodiment of the present application, by providing the first outgoing portion 112 having the first electrical component 114 and the second outgoing portion 113 having the second electrical component 115, and combining manufacturing tolerances, the shortest creepage distance between the outermost winding 120 and the second electrical component 115 is greater than or equal to 7.5mm, wherein creepage distance refers to the distance between the winding 120 connected to the first electrical component 114 and the second electrical component 115 to be electrically connected along the board surface of the circuit board 110, and by providing the second electrical component 115 away from the live zone of the winding 120, the safety performance of the planar transformer 100 is improved, the second electrical component 115 is prevented from being affected by the winding 120, the operating state of the planar transformer 100 can be more stable, and even if an error occurs in production, the minimum creepage distance of 7.5mm is sufficient to ensure the safety performance of the planar transformer 100. Usually, to ensure safety, the outermost winding only discharges the primary winding or only discharges the secondary winding, and the primary winding and the secondary winding may be fabricated on the same layer or different layers of the wire carrier portion 111. It is understood that the number of primary windings may be 1 or 2, and the number of secondary windings may be 1 or more than 1.

Referring to fig. 1 to fig. 2, further, any connection position between the first wire-out portion 112 and the wire-carrying portion 111 is a first connection position, any connection position between the second wire-out portion 113 and the wire-carrying portion 111 is a second connection position, different first connection positions and different second connection positions have a plurality of connection lines a, and an extending direction of any one of the connection lines a forms an included angle with a length direction b of the second wire-out portion 113. The extending direction of the connecting line a and the length direction b of the second outgoing line portion 113 are arranged at an included angle, that is, the second outgoing line portion 113 is arranged obliquely with respect to the line carrying portion 111, compared with the case that the extending direction of the connecting line a and the length direction b of the second outgoing line portion 113 are arranged in parallel, the overall length dimension of the circuit board 110 can be reduced, and the miniaturization of the flat-plate transformer 100 is facilitated on the premise that the safety performance of the flat-plate transformer 100 is ensured.

Referring to fig. 1 and 3, further, an extending direction of at least one connection line a is perpendicular to a length direction b of the second wire-out portion 113. The extending direction of the connecting line a is perpendicular to the length direction b of the second outgoing line portion 113, so that the length of the circuit board 110 in the extending direction of the connecting line a is reduced to the greatest extent on the premise of ensuring the working performance of the circuit board 110, the area of the circuit board 110 is reduced, the production cost of the flat-plate transformer 100 is further reduced, and the quantitative production of the flat-plate transformer 100 is facilitated.

As can be understood from fig. 4, the second wire outlet portion 113 may include a wire outlet portion 1131 and a connecting portion 1132, wherein the wire outlet portion 1131 is substantially a rectangular plate, and is provided with a plurality of second electrical components 115. The connecting sub-portion 1132 connects the carrier portion 111 and the outlet sub-portion 1131, and the second connection position is located in the connecting sub-portion 1132. The second wire outlet part 113 is arranged to include a wire outlet sub-part 1131 and a connecting sub-part 1132, the wire outlet sub-part 1131 is connected to the wire loading part 111 through the connecting sub-part 1132, and the plurality of second electric connection parts 115 are all arranged on the wire outlet sub-part 1131, so that the distance between the second electric connection parts 115 and the winding 120 connected with the first electric connection part 114 is increased, and the improvement of the safe working performance of the planar transformer 100 is facilitated.

In some embodiments, referring to fig. 4 (fig. 4 illustrates an EQ core planar transformer as an example, the practical application may not limit the type of the planar transformer), the extending direction of the wide side e of the outgoing line portion 1131 away from the wire loading portion 111 may avoid the wire loading portion 111, and the extending direction of the wide side e of the outgoing line portion 1131 close to the wire loading portion 111 passes through the wire loading portion 111. One end of the wire outgoing sub-portion 1131 extends in a direction away from the wire loading portion 111, so that the circuit board 110 is substantially in a shape of a "Z", as shown in fig. 5, a plurality of circuit boards 110 in the shape of a "Z" can be spliced together in a staggered manner, thereby increasing the number of typesetting of the circuit boards 110 in a unit area of the board, improving the utilization rate of the board, reducing the generation of waste boards, being more environment-friendly, and further reducing the production cost of the flat-plate transformer 100.

Further, referring to fig. 1, the plurality of second electrical components 115 may be arranged along the width direction of the outlet sub-portion 1131, and the outlet sub-portion 1131 has two wide sides e, the plurality of second electrical components 115 are disposed closer to one of the two wide sides e, which is far away from the wire loading portion 111, and the dimension of the outlet sub-portion 1131 in the length direction can be shrunk to be smaller by designing the plurality of second electrical components 115 to be arranged along the width direction of the outlet sub-portion 1131 and to be disposed closer to one of the two wide sides e, which is far away from the wire loading portion 111.

Alternatively, referring to fig. 4, the plurality of second electrical components 115 may be arranged along the length direction of the wire outlet portion 1131, the wire outlet portion 1131 has two long sides f, and the plurality of second electrical components 115 are disposed closer to the long side f far away from the wire loading portion 111 of the two long sides f. The plurality of second electrical components 115 are arranged along the length direction of the outlet portion 1131 and are disposed closer to the long side f far away from the wire loading portion 111 of the two long sides f, so that the dimension of the outlet portion 1131 in the width direction can be reduced to be smaller. It can be understood that the planar transformer 100 with the arrangement directions of the plurality of second electrical connection parts 115 more meeting the requirements can be selected according to the actual use requirements and the production requirements.

In other embodiments, referring to fig. 6 to 7, both wide sides of the line outgoing portion 1131 can penetrate through the line loading portion 111, the line outgoing portion 1131 has a first long side c and a second long side d parallel to each other, the first long side c is closer to the line loading portion 111 than the second long side d, the connecting portion 1132 is connected to any end of the first long side c, and the first long side c, the connecting portion 1132 and the line loading portion 111 together form a spacing slot 130. Compared with the conventional planar transformer, the size of the circuit board 110 in the length direction is reduced by at least 2mm to 4mm, the area of the circuit board 110 is reduced by at least 5% to 20%, the overall size of the planar transformer 100 can be effectively reduced, and the miniaturization of the planar transformer 100 is realized.

Further, a plurality of second electrical components 115 may be disposed along the length direction of the outlet sub-portion 1131, and in the width direction of the outlet sub-portion 1131, the projection of the second electrical components 115 on the first long side c falls into the spacing slot 130. The projection of the second electric connecting piece 115 on the first long edge c is designed to fall into the spacing groove 130, so that the second electric connecting piece 115 is far away from the winding 120 to a greater extent, miniaturization of the flat-plate transformer 100 is facilitated, and safety performance and stability of the flat-plate transformer 100 are improved.

In order to reduce the area of the flat-panel transformer 100, the projection of the first wire outgoing portion 112 on the wire loading portion 111 is located within the wire loading portion 111 along the width direction of the wire outgoing sub-portion 1131. In addition, the plurality of first electric parts 114 disposed at the first wire-out portions 112 and the plurality of second electric parts 115 disposed at the second wire-out portions 113 may be at least one of through holes, half holes, or pads.

Referring to fig. 1, the planar transformer 100 may further include a magnetic core 140, and the circuit board 110 is disposed on the magnetic core 140. When an ac current is applied to the primary winding, an ac magnetic flux is generated in the magnetic core 140, and a voltage (or current) is induced in the secondary winding. The planar transformer 100 is further provided with a magnetic core 140, and the magnetic core 140 can increase magnetic permeability, reduce eddy current loss and has anti-interference effect. Further, the magnetic core 140 may be an iron powder core, a permalloy powder core, a high magnetic flux powder core, or an sendust core. The iron powder core is composed of carbon-based ferromagnetic powder and resin carbon-based ferromagnetic powder, and has low cost and good direct current superposition performance. The permalloy powder core has the advantages of large magnetic conductivity range, low loss and excellent temperature stability. The high magnetic flux powder core has high magnetic induction intensity, high direct current bias capability and smaller volume. The ferrosilicon-aluminum powder core has low loss, the magnetostriction coefficient is close to 0, no noise is generated when the ferrosilicon-aluminum powder core works under different frequencies, and the ferrosilicon-aluminum powder core has excellent cost performance.

In a second aspect, an embodiment of the present application provides an electronic device, which may include a housing and the planar transformer 100 described above, where the planar transformer 100 is disposed in the housing. The electronic device can be a charging plug, a switching power supply and other devices.

In the embodiment of the application, by arranging the first outgoing portion 112 with the first electric connecting part 114 and the second outgoing portion 113 with the second electric connecting part 115, the shortest creepage distance between the winding 120 connected with the first electric connecting part 114 and the second electric connecting part 115 is greater than or equal to 7.5mm, and by arranging the second electric connecting part 115 away from the charged area of the winding 120, the safety performance of the flat-plate transformer 100 is improved, the second electric connecting part 115 is prevented from being affected by the winding 120, the working state of the flat-plate transformer 100 can be more stable, even if an error is generated in production, the minimum creepage distance of 7.5mm is also enough to ensure the safety performance of the flat-plate transformer 100, and further the safety performance and the stability performance of electronic equipment are favorably improved.

The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present application, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of the description, but it is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation and operate, and therefore the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the above terms can be understood according to the specific situation by those skilled in the art.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A planar transformer, comprising:

2. The flat plate transformer according to claim 1, wherein any connection position of the first wire outlet portion and the wire carrying portion is a first connection position, any connection position of the second wire outlet portion and the wire carrying portion is a second connection position, a plurality of connecting lines are arranged between different first connection positions and different second connection positions, and the extending direction of any one of the connecting lines is arranged at an angle to the length direction of the second wire outlet portion.

3. The planar transformer according to claim 2, wherein the extending direction of at least one of the connection lines is perpendicular to the length direction of the second wire-outlet portion.

4. The planar transformer according to claim 2, wherein the second outlet portion includes:

5. The flat panel transformer of claim 4, wherein an extending direction of the wide side of the outlet line sub-portion away from the line loading portion is turned away from the line loading portion, and an extending direction of the wide side of the outlet line sub-portion close to the line loading portion passes through the line loading portion.

6. The planar transformer of claim 4, wherein the plurality of second electrical components are arranged along the width direction of the outlet sub-portion, the outlet sub-portion has two wide sides, and the plurality of second electrical components are disposed closer to one of the two wide sides away from the wire loading portion; or alternatively

7. The planar transformer of claim 4, wherein both wide sides of the wire outgoing portion pass through the wire loading portion, the wire outgoing portion has a first long side and a second long side parallel to each other, the first long side is closer to the wire loading portion than the second long side, the connector portion is connected to either end of the first long side, and the first long side, the connector portion and the wire loading portion together form a spacing slot.

8. The planar transformer according to claim 7, wherein a plurality of the second electrical parts are disposed along a length direction of the outlet sub-portion, and a projection of the second electrical parts on the first long side falls into the spacing groove in a width direction of the outlet sub-portion.

9. The planar transformer according to any one of claims 1 to 8, further comprising;

a magnetic core, the circuit board set in the magnetic core.

10. An electronic device comprising a housing and a planar transformer according to any of claims 1-8, the planar transformer being disposed within the housing.