Switching transformer and switching power supply

Abstract

The utility model discloses a switch transformer and a switch power supply, the switch transformer includes: a transformer skeleton including a cylindrical portion, a first end plate, a second end plate and a first baffle plate, the first end plate, the second end plate and the first baffle plate jointly define a primary side wiring channel and a secondary side wiring channel, the first end plate is provided with a first avoidance gap, and the second end plate is provided with a second avoidance gap; the first baffle plate is provided with a second avoiding gap, and the second end plate is provided with a first wiring gap and a second wiring gap. The magnetic powder core is annularly arranged on the transformer framework and connected with the first end plate and the second end plate; the primary winding is wound in the primary wiring groove; and the secondary winding is wound in the secondary wiring groove. According to the technical scheme, the assembling efficiency of the switch transformer can be improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of transformers, and in particular to a switching transformer and a switching power supply. Background Art

[0002] A switching transformer is a special type of transformer whose main function is to achieve effective conversion from input voltage to output voltage by controlling the on and off of the switching device. It is mainly used in power supply systems, such as switching power supplies and inverters. The switching transformer of the related technology usually includes a transformer skeleton, a magnetic powder core, a primary winding, a secondary winding and an epoxy board. The primary winding and the secondary winding are respectively wound in the primary wiring groove and the secondary wiring groove of the transformer skeleton. The input lead and the output lead of the secondary winding need to pass through the epoxy board and be fixed with glue. This process is cumbersome and difficult to operate. In addition, each lead of the secondary winding needs to be pulled out from the epoxy board, which takes time and the assembly efficiency is low. Utility Model Content

[0003] The purpose of the present application is to provide a switching transformer and a switching power supply, aiming to improve the assembly efficiency of the switching transformer.

[0004] According to a first aspect of the present application, a switching transformer is provided, comprising:

[0005] A transformer skeleton, comprising a cylindrical portion, a first end plate, a second end plate and a first baffle, wherein the first end plate and the second end plate are respectively arranged at opposite ends of the cylindrical portion, the first baffle is arranged between the first end plate and the second end plate, the first end plate, the second end plate and the first baffle together define a primary wiring groove and a secondary wiring groove, the first end plate is provided with a first avoidance gap, the first baffle is provided with a second avoidance gap, the second end plate is provided with a first wiring gap and a second wiring gap, and the second wiring gap, the first wiring gap, the second avoidance gap and the first avoidance gap are all located on a first side of the transformer skeleton;

[0006] A magnetic powder core is arranged in a ring around the transformer frame and connected to the first end plate and the second end plate respectively;

[0007] A primary winding is wound in the primary wiring groove; and

[0008] The secondary winding is wound in the secondary wiring groove, the input lead of the secondary winding passes through the first wiring gap and the second avoidance gap respectively and extends into the secondary wiring groove, and the output lead of the secondary winding passes through the first avoidance gap and the second wiring gap respectively and extends from the second wiring gap.

[0009] In some embodiments, the first baffle is provided with a third avoidance gap, and the second end plate is provided with a third routing gap and a fourth routing gap, wherein the third avoidance gap, the third routing gap, and the fourth routing gap are all located on the second side of the transformer skeleton, and the second side and the first side are arranged opposite to each other;

[0010] The input lead of the primary winding passes through the third routing gap and the third avoidance gap respectively and extends out from the third routing gap, and the output lead of the primary winding extends out from the fourth routing gap.

[0011] In some embodiments, a power supply pin is provided on a surface of the second end plate facing away from the first baffle;

[0012] The switch transformer comprises a power supply winding, the power supply winding is wound in the primary wiring groove, and the power supply lead wire led out of the power supply winding is welded and fixed to the power supply pin foot.

[0013] In some embodiments, the transformer skeleton includes a second baffle, which is disposed between the first end plate and the second end plate and encloses a shielding area with the first baffle;

[0014] The second baffle is provided with a fourth avoidance gap, and the fourth avoidance gap is located on the first side. The input lead of the secondary winding passes through the first routing gap, the second avoidance gap and the fourth avoidance gap respectively and extends out from the first routing gap.

[0015] In some embodiments, the primary winding and the secondary winding are both formed by insulating twisted wires with at least three layers of polyimide film wrapped around their outer surfaces.

[0016] In some embodiments, the width of the second end plate is greater than the width of the first end plate.

[0017] In some embodiments, the magnetic powder core is an EQ40 / 40 magnetic powder core.

[0018] In some embodiments, the first end plate includes a first end plate body and a strip-shaped boss protruding from a surface of the first end plate body away from the cylindrical portion, the number of the strip-shaped bosses is two, the two strip-shaped bosses are respectively arranged at two ends of the first end plate body along its width direction, and the two strip-shaped bosses and the first end plate body are enclosed to form a first limiting groove;

[0019] The second end plate comprises a second end plate body and two inverted L-shaped bosses, the two inverted L-shaped bosses are respectively connected to two ends of the second end plate body along its width direction, and the two inverted L-shaped bosses and the second end plate body are enclosed to form a second limiting groove;

[0020] The width of the first limiting groove and the width of the second limiting groove are both the same as the width of the magnetic powder core.

[0021] In some embodiments, the transformer frame is made of phenolic resin.

[0022] According to a second aspect of the present application, a switching power supply is provided, comprising the switching transformer described above.

[0023] The beneficial effects of the embodiments of the present application are as follows: the switch transformer involved in the present application, by providing multiple routing gaps on the transformer frame, can allow the input and output leads on the secondary winding to be separately routed out, which can avoid the need for the input and output leads of the secondary winding to be fixed by gluing through the epoxy board, thereby improving the assembly efficiency of the switch transformer. In addition, by providing a first avoidance gap on the first end plate and a second avoidance gap on the first baffle plate, the routing path of the input and output leads of the secondary winding is optimized, which can reduce the extra space occupied by the input and output wiring in the height direction, and at the same time reduce the difficulty of winding the secondary winding, which is conducive to the realization of the automated assembly of the switch transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0025] Figure 1 A schematic diagram of the structure of a switching transformer provided in an embodiment of the present application;

[0026] Figure 2 for Figure 1 The structural exploded diagram of the switching transformer is shown;

[0027] Figure 3 for Figure 1 The schematic diagram of the structure of the transformer skeleton of the switching transformer shown is at an angle;

[0028] Figure 4 for Figure 1 The schematic diagram of the structure of the transformer skeleton of the switching transformer shown is at another angle;

[0029] Figure 5 for Figure 1 The schematic diagram of the structure of the transformer skeleton of the switching transformer is shown at another angle. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without carrying out creative work are within the scope of protection of this application.

[0031] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0032] In the description of the present application, it should be noted that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present application and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present application. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0033] In the description of the present application, it should be noted that the use of terms such as "first" and "second" to limit components is merely to facilitate the distinction between corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present application.

[0034] The technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] Figure 1 A schematic diagram of the structure of a switching transformer provided in an embodiment of the present application is shown in FIG. Figure 2 for Figure 1 The exploded diagram of the switching transformer is shown in Figure 1. Figure 1 and Figure 2The switching transformer comprises: a transformer skeleton 10, a magnetic powder core 20, a primary winding 30 and a secondary winding 40; wherein the transformer skeleton 10 is a mounting support structure for the primary winding 30 and the secondary winding 40, and the magnetic powder core 20 is arranged around the transformer skeleton 10; the transformer skeleton 10 has a coaxially arranged secondary wiring groove 10b and a primary wiring groove 10a, and the secondary wiring groove 10b is located above the primary wiring groove 10a; the secondary winding 40 is wound in the secondary wiring groove 10b, and the primary winding 30 is wound in the primary wiring groove 10a; the lead wires of the secondary winding 40 and the lead wires of the primary winding 30 are respectively located on opposite sides of the transformer skeleton 10.

[0036] For transformer skeleton 10, please combine Figures 3 to 5 See also Figure 1 In some embodiments, the transformer skeleton 10 includes a cylindrical portion 11 , a first end plate 12 , a second end plate 13 and a first baffle 14 .

[0037] The cylindrical portion 11 is a cylindrical structure with a central hole.

[0038] The first end plate 12 includes a first end plate body 121 and two strip-shaped bosses 122. The first end plate body 121 extends outward from one end of the cylindrical portion 11 to form a plate-like structure surrounding one end of the cylindrical portion 11. The longitudinal cross-sectional shape of the plate-like structure is roughly circular, and each end has a square combined outline. The two strip-shaped bosses 122 protrude outward from the surface of the plate-like structure away from the cylindrical portion 11, and a strip-shaped boss 122 extends corresponding to a longer side of a square. The two strip-shaped bosses 122 and the first end plate body 121 together enclose a first limiting groove (not shown), and the first limiting groove is used to limit the first magnetic powder core 201 to be described below.

[0039] One of the two strip-shaped bosses 122 is provided with a first avoidance notch 1201 penetrating through two opposite surfaces thereof, wherein the opening direction of the first avoidance notch 1201 is perpendicular to the central axis direction of the cylindrical portion 11. The first avoidance notch 1201 is used for passing the output lead 402 of the secondary winding to be described below. Specifically, there are two first avoidance notches 1201, which are arranged at intervals in the extension direction of the strip-shaped boss 122, and the two first avoidance notches 1201 are respectively used for passing the output leads of different polarities of the secondary winding 40.

[0040] Furthermore, the opening depths of the two first avoidance gaps 1201 are both greater than or equal to twice the wire diameter of the output lead of the secondary winding 40. In this way, even if the output lead is bent, the bent portion can still be accommodated in the first avoidance gap 1201 to reduce the volume of the switching transformer.

[0041] The second end plate 13 includes a second end plate body 131 and two inverted L-shaped bosses 132. The second end plate body 131 extends outward from the other end of the cylindrical portion 11 to form a plate-like structure surrounding the other end of the cylindrical portion 11. The longitudinal cross-sectional shape of the plate-like structure is also roughly circular, and each end has a square combined outline. The two inverted L-shaped bosses 132 are respectively connected to the longer sides of the two squares, and an inverted L-shaped boss 132 and a strip boss 122 are located on the same side of the transformer skeleton 10. Among them, the two second strip bosses 122 and the second end plate body 131 jointly enclose the second limiting groove, and the second limiting groove is used to limit the second magnetic powder core 202 to be described below.

[0042] One of the two inverted L-shaped bosses 132 is provided with a first routing notch 1301 and a second routing notch 1302 that penetrate through its two opposite surfaces. The opening direction of the first routing notch 1301 and the opening direction of the second routing notch 1302 are both perpendicular to the central axis direction of the cylindrical portion 11. The first routing notch 1301 is used for the input lead 401 of the secondary winding to be described below to pass through, and the second routing notch 1302 is used for the output lead 402 of the secondary winding to be described below to pass through. Specifically, the number of the first routing notches 1301 and the number of the second routing notches 1302 are both two, and the two first routing notches 1301 and the two second routing notches 1302 are spaced apart in the extension direction of the inverted L-shaped boss 132, and the two first routing notches 1301 are respectively used for the input leads of different polarities of the secondary winding 40 to pass through, and the two second routing notches 1302 are respectively used for the output leads of different polarities of the secondary winding 40 to pass through.

[0043] The two opposite side walls of the opening located at the first wiring gap 1301 are closer to each other than the two opposite side walls inside the first wiring gap 1301. The two opposite side walls of the opening located at the second wiring gap 1302 are closer to each other than the two opposite side walls inside the second wiring gap 1302. In this way, the input lead 401 and the output lead of the secondary winding are confined therein and are not easy to escape.

[0044] The other of the two inverted L-shaped bosses 132 is provided with a third routing gap 1303 and a fourth routing gap 1304 penetrating through its two opposite surfaces, and the opening direction of the third routing gap 1303 and the opening direction of the fourth routing gap 1304 are both perpendicular to the central axis direction of the cylindrical portion 11. The third routing gap 1303 is used for the input lead of the primary winding 30 to be described below to pass through, and the fourth routing gap 1304 is used for the output lead of the primary winding 30 to be described below to pass through. Specifically, the number of the third routing gap 1303 and the number of the fourth routing gap 1304 are both two, and the two third routing gaps 1303 and the two fourth routing gaps 1304 are arranged at intervals in the extension direction of the inverted L-shaped boss 132, and the two third routing gaps 1303 are respectively used for the input leads of different polarities of the primary winding 30 to pass through, and the two fourth routing gaps 1304 are respectively used for the output leads of different polarities of the primary winding 30 to pass through.

[0045] Continue as Figures 3 to 5 As shown, in some embodiments, the width of the second end plate 13 is greater than the width of the first end plate 12. The wider second end plate 13 can be used as a foolproof design. At the same time, the wider second end plate 13 is conducive to the lead wires of the primary winding 30 and the secondary winding 40 in the automation process. It should be noted that the width of the second end plate 13 mentioned here specifically refers to the distance between the two inverted L-shaped bosses 132. The width of the first end plate 12 specifically refers to the distance between the two inverted L-shaped bosses 122.

[0046] The two inverted L-shaped bosses 132 are configured to directly contact the circuit board when the switch transformer is assembled on the circuit board, and other electrical components are suspended relative to the circuit board. This increases the contact area between the magnetic powder core 20 and the air, effectively improving the heat dissipation capacity, which is particularly important for high-power switch transformers. Of course, it also helps to weld the leads of the primary winding 30 and the secondary winding 40 on the transformer frame to the circuit board, and quickly dissipate the heat generated during welding.

[0047] The first baffle 14 is disposed between the first end plate body 121 and the second end plate body 131, and extends outward from the outer circumference of the cylindrical portion 11 to form a plate-like structure surrounding the cylindrical portion 11, and the longitudinal cross-section of the plate-like structure is generally circular. The first baffle 14, the first end plate body 121, and the second end plate body 131 together define the primary side wiring groove 10a and the secondary side wiring groove 10b.

[0048] The first baffle 14 is provided with a second avoidance gap 1401, the opening direction of the second avoidance gap 1401 is perpendicular to the central axis direction of the cylindrical portion 11, and the second avoidance gap 1401, the first avoidance gap 1201, the first wiring gap 1301 and the second wiring gap 1302 are all located on the first side of the transformer skeleton 10. The second avoidance gap 1401 is used for the input lead 401 of the secondary winding to pass through.

[0049] Furthermore, the first baffle 14 is also provided with a third avoidance gap 1402, the opening direction of the third avoidance gap 1402 is also perpendicular to the central axis direction of the cylindrical portion 11, and the third avoidance gap 1402, the third routing gap 1303 and the fourth routing gap 1304 are all located on the second side of the transformer skeleton 10, and the second side and the first side are arranged oppositely. Among them, the third avoidance gap 1402 is used for the input lead of the primary winding 30 to pass through. Furthermore, a branching gap is also provided on both sides of the third avoidance gap 1402, and the branching gap is used to clamp the input leads of different polarities passing through the third avoidance gap 1402.

[0050] In order to increase the creepage distance between the primary winding 30 and the secondary winding 40, in some embodiments, the transformer skeleton 10 further includes a second baffle 15, which is disposed between the first end plate body 121 and the second end plate body 131 and is located above the first baffle 14. The second baffle 15 and the first baffle 14 enclose a shielding area (not shown), and the shortest distance between the second baffle 15 and the first baffle 14 is 4 mm.

[0051] The second baffle 15 is provided with a fourth avoidance gap 1501, the opening direction of the fourth avoidance gap 1501 is perpendicular to the central axis direction of the cylindrical portion 11, and the fourth avoidance gap 1501, the second avoidance gap 1401, the first avoidance gap 1201, the first wiring gap 1301 and the second wiring gap 1302 are all located on the first side of the transformer skeleton 10. The fourth avoidance gap 1501 is also used for the input lead 401 of the secondary winding to pass through.

[0052] In some embodiments, the transformer skeleton 10 is made of phenolic resin. This is selected after comprehensive consideration of cost, material insulation capacity, injection molding performance, etc. The transformer skeleton 10 has a temperature resistance of 150° C. and a fire protection rating of 94V-0.

[0053] The magnetic powder core 20 is an EQ type magnetic powder core 20, which is a standard part with different sizes. In each embodiment of the present application, EQ40 / 40 type PC40 ferrite is used as an example.

[0054] like Figure 2As shown, in some embodiments, the magnetic powder core 20 includes a first magnetic powder core 201 and a second magnetic powder core 202, wherein the first magnetic powder core 201 is partially embedded in the first limiting groove, and the cylinder in the middle of the first magnetic powder core 201 is inserted into the central hole of the cylindrical portion 11. The second magnetic powder core 202 is partially embedded in the second limiting groove, and the cylinder in the middle of the second magnetic powder core 202 is inserted into the central hole of the cylindrical portion 11. The first magnetic powder core 201 and the second magnetic powder core 202 can be fixed to each other by gluing.

[0055] In order to better install the magnetic powder core 20 and the transformer frame 10, the width of the first limiting groove and the width of the second limiting groove are the same as the width of the magnetic powder core 20. In other words, the widths of the first magnetic powder core 201 and the second magnetic powder core 202 are the same, and the width of the first magnetic powder core 201 is the same as the width of the first limiting groove, and the width of the second magnetic powder core 202 is the same as the width of the second limiting groove.

[0056] For the primary winding 30, the primary winding 30 is wound in the primary wiring groove 10a, and the input leads of the primary winding 30 respectively pass through the third wiring gap 1303 and the third avoidance gap 1402 and extend from the third wiring gap 1303. Specifically, the input leads of different polarities each pass through a third wiring gap 1303 and are wound in the primary winding groove. The output leads of the primary winding 30 extend from the fourth wiring gap 1304. Specifically, the output leads of different polarities extend from the same third avoidance gap 1402 and then pass through different branching gaps, and finally each pass through a fourth wiring gap 1304 and extend out of the fourth wiring gap 1304.

[0057] For the secondary winding 40, the secondary winding 40 is wound in the secondary wiring groove 10b, and the input lead 401 of the secondary winding passes through the first wiring gap 1301 and the second avoidance gap 1401 respectively and extends into the secondary wiring groove 10b. Specifically, the input leads of different polarities respectively pass through a first wiring gap 1301 and a second avoidance gap 1401 and then extend into the secondary wiring groove 10b. The output lead 402 of the secondary winding respectively passes through the first avoidance gap 1201 and the second wiring gap 1302 and then extends from the second wiring gap 1302. Specifically, the output leads of different polarities respectively pass through their respective first avoidance gaps 1201 and their respective second wiring gaps 1302 and then extend from their respective second wiring gaps 1302.

[0058] The switch transformer involved in the present application, by opening a plurality of routing gaps on the transformer frame 10, can allow the input and output leads on the secondary winding 40 to be separately routed out, which can avoid the input and output leads of the secondary winding 40 still needing to pass through the epoxy board for glue fixation, thereby improving the assembly efficiency of the switch transformer. In addition, by opening a first avoidance gap 1201 on the first end plate 12 and a second avoidance gap 1401 on the first baffle plate 14, the routing path of the input and output leads of the secondary winding 40 is optimized, which can reduce the extra space occupied by the input and output wiring in the height direction, and at the same time reduce the difficulty of winding the secondary winding 40, which is conducive to the realization of the automated assembly of the switch transformer.

[0059] like Figure 3 or Figure 5 As shown, in some further embodiments, a power supply pin 501 is provided on a surface of the second end plate 13 facing away from the first baffle plate 14 .

[0060] The switching transformer comprises a power supply winding 50 , which is wound in the primary wiring groove 10 a , and a power supply pin led out of the power supply winding 50 is welded and fixed to a power supply pin foot 501 .

[0061] Specifically, the power supply pin 501 is located at one end of the inverted L-shaped boss 132 along its extension direction, and the power supply pin, the first routing gap 1301 and the second routing gap 1302 are all arranged on the same inverted L-shaped boss 132. The power supply pin 501 and the lead of the secondary winding 40 to be described below are arranged on the same side. Such a layout can reduce the electromagnetic field caused by the current change, thereby reducing the radiation interference of the circuit and the interference to the surrounding circuits, thereby ensuring better electromagnetic compatibility in the transformer and its surrounding circuits. Furthermore, the inverted L-shaped boss 132 where the power supply pin 501 is located is provided with a power supply routing gap to facilitate the lead of the power supply winding 50 to pass through.

[0062] Based on the same technical concept, the present application also provides a switching power supply having a switching transformer in any of the above embodiments. For the specific structure of the switching transformer, please refer to the description of the above embodiments, which will not be elaborated here.

[0063] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A switching transformer, characterized in that: include: A transformer skeleton, comprising a cylindrical portion, a first end plate, a second end plate and a first baffle, wherein the first end plate and the second end plate are respectively arranged at opposite ends of the cylindrical portion, the first baffle is arranged between the first end plate and the second end plate, the first end plate, the second end plate and the first baffle together define a primary wiring groove and a secondary wiring groove, the first end plate is provided with a first avoidance gap, the first baffle is provided with a second avoidance gap, the second end plate is provided with a first wiring gap and a second wiring gap, and the second wiring gap, the first wiring gap, the second avoidance gap and the first avoidance gap are all located on a first side of the transformer skeleton; A magnetic powder core is arranged in a ring around the transformer frame and connected to the first end plate and the second end plate respectively; A primary winding is wound in the primary wiring groove; and The secondary winding is wound in the secondary wiring groove, the input lead of the secondary winding passes through the first wiring gap and the second avoidance gap respectively and extends into the secondary wiring groove, and the output lead of the secondary winding passes through the first avoidance gap and the second wiring gap respectively and extends from the second wiring gap.

2. The switching transformer according to claim 1, characterized in that: The first baffle plate is provided with a third avoidance gap, and the second end plate is provided with a third routing gap and a fourth routing gap, wherein the third avoidance gap, the third routing gap, and the fourth routing gap are all located on the second side of the transformer skeleton, and the second side and the first side are arranged opposite to each other; The input lead of the primary winding passes through the third routing gap and the third avoidance gap respectively and extends out from the third routing gap, and the output lead of the primary winding extends out from the fourth routing gap.

3. The switching transformer according to claim 1, characterized in that: A power supply pin is provided on a surface of the second end plate facing away from the first baffle; The switch transformer comprises a power supply winding, the power supply winding is wound in the primary wiring groove, and the power supply lead wire led out of the power supply winding is welded and fixed to the power supply pin foot.

4. The switching transformer according to claim 1, characterized in that: The transformer skeleton includes a second baffle, which is arranged between the first end plate and the second end plate and encloses a shielding area with the first baffle; The second baffle is provided with a fourth avoidance gap, and the fourth avoidance gap is located on the first side. The input lead of the secondary winding passes through the first routing gap, the second avoidance gap and the fourth avoidance gap respectively and extends out from the first routing gap.

5. The switching transformer according to any one of claims 1 to 4, characterized in that: The primary winding and the secondary winding are both composed of at least three layers of polyimide film wrapped around the outer surface of the insulated twisted wire.

6. The switching transformer according to any one of claims 1 to 4, characterized in that: The width of the second end plate is greater than the width of the first end plate.

7. The switching transformer according to any one of claims 1 to 4, characterized in that: The magnetic powder core is EQ40 / 40 magnetic powder core.

8. The switching transformer according to claim 7, characterized in that: The first end plate comprises a first end plate body and a strip-shaped boss protruding from a surface of the first end plate body away from the cylindrical portion, the number of the strip-shaped bosses is two, the two strip-shaped bosses are respectively arranged at two ends of the first end plate body along its width direction, and the two strip-shaped bosses and the first end plate body are enclosed to form a first limiting groove; The second end plate comprises a second end plate body and two inverted L-shaped bosses, the two inverted L-shaped bosses are respectively connected to two ends of the second end plate body along its width direction, and the two inverted L-shaped bosses and the second end plate body are enclosed to form a second limiting groove; The width of the first limiting groove and the width of the second limiting groove are both the same as the width of the magnetic powder core.

9. The switching transformer according to any one of claims 1 to 4, characterized in that: The transformer frame is made of phenolic resin.

10. A switching power supply, characterized in that: Comprising a switching transformer as claimed in any one of claims 1 to 9.

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