A planar transformer and a power supply device

Abstract

The present invention relates to the field of planar transformers, and particularly to a planar transformer and a power supply device. The planar transformer includes a magnetic core module and a winding module. The magnetic core module includes a first magnetic core and a second magnetic core arranged opposite to each other. The second magnetic core includes a body part and a magnetic core middle column. The magnetic core middle column is arranged on the surface of the body part facing the first magnetic core. The winding module is sleeved on the magnetic core middle column. The winding module includes a substrate and a first winding unit. The substrate includes a first wiring layer. The first wiring layer includes a first wiring area. The first winding unit includes at least two first windings arranged at intervals in the first wiring area. At least two first windings are connected in parallel with each other. In this embodiment, by dividing the winding unit with an overly wide wire diameter into at least two windings and then connecting at least two windings in parallel, it is possible to avoid an overly wide wire diameter of the winding unit, thereby reducing the AC loss and eddy current loss of the winding unit, and further improving the efficiency of the planar transformer and reducing the temperature rise of the planar transformer.

Description

Technical Field

[0001] The present invention relates to the field of planar transformers, and particularly to a planar transformer and a power supply device. Background Art

[0002] Planar transformers have the characteristics of high efficiency and energy saving, low radiation, low noise, high temperature resistance, moisture protection and moisture proofing. Compared with traditional transformers, planar transformers consume less power and have lower energy consumption. They can not only effectively reduce the electricity cost, but also reduce environmental pollution, thus achieving the purpose of energy conservation and environmental protection.

[0003] At present, when a planar transformer is applied to high-power occasions, since the number of turns of the primary winding and some secondary windings is relatively small and the current to flow through is large, the wire diameter of a single-turn winding is often designed to be relatively wide. However, in high-frequency applications, when the wire diameter of a single-turn winding is too wide, serious skin effect and proximity effect will occur, thereby increasing the AC losses of the planar transformer, namely skin losses and proximity losses. The increased AC losses reduce the efficiency of the planar transformer. Moreover, the wider the wire diameter of a single-turn winding is, the more eddy current losses usually increase, resulting in too high temperature rise of the planar transformer, which not only reduces the efficiency of the planar transformer, but also reduces the stability of the planar transformer. Summary of the Invention

[0004] An object of the present invention is to provide a planar transformer and a power supply device to solve the technical problems of low efficiency or low stability of traditional planar transformers.

[0005] In a first aspect, an embodiment of the present invention provides a planar transformer, including:

[0006] A magnetic core module, including a first magnetic core and a second magnetic core arranged oppositely, the second magnetic core including a body part and a magnetic core middle column, and the magnetic core middle column being arranged on a surface of the body part facing the first magnetic core; and

[0007] A winding module, located between the body part and the first magnetic core and sleeved on the magnetic core middle column, the winding module including a substrate and a first winding unit, the substrate including a first wiring layer, the first wiring layer including a first wiring area, and the first winding unit including at least two first windings arranged at intervals in the first wiring area, and each of the first windings being connected in parallel.

[0008] In some embodiments, the wire widths of at least two of the first windings increase along the width direction of the body part and away from the magnetic core middle column.

[0009] In some embodiments, an air gap is formed between the middle column of the magnetic core and the first magnetic core. The first wiring layer is disposed on one side of the substrate close to the air gap. The substrate further includes a second wiring layer disposed on the other side of the substrate away from the air gap. The first wiring layer further includes a second wiring area disposed relatively closer to the middle column of the magnetic core than the first wiring area. The second wiring layer includes a third wiring area corresponding to the first wiring area and a fourth wiring area corresponding to the second wiring area. The winding module further includes a second winding unit, a third winding unit, and a fourth winding unit. The second winding unit is disposed in the third wiring area, the third winding unit is disposed in the second wiring area, and the fourth winding unit is disposed in the fourth wiring area. The first winding unit and the second winding unit are connected in series to form a first secondary winding, and the third winding unit and the fourth winding unit are connected in series to form a second secondary winding.

[0010] In some embodiments, the second winding unit includes at least two second windings spaced apart and disposed in the third wiring area. At least two of the second windings are connected in parallel with each other, and each of the second windings is disposed corresponding to each of the first windings along the extending direction of the middle column of the magnetic core.

[0011] In some embodiments, the line widths of at least two of the second windings increase along the width direction of the body portion and away from the middle column of the magnetic core.

[0012] In some embodiments, the third winding unit includes at least two third windings spaced apart and disposed in the second wiring area. At least two of the third windings are connected in parallel with each other.

[0013] In some embodiments, the fourth winding unit includes at least two fourth windings spaced apart and disposed in the fourth wiring area. At least two of the fourth windings are connected in parallel with each other, and each of the fourth windings is disposed corresponding to each of the third windings along the extending direction of the middle column of the magnetic core.

[0014] In some embodiments, the line widths of at least two of the fourth windings or at least two of the third windings increase along the width direction of the body portion and away from the middle column of the magnetic core.

[0015] In some embodiments, the substrate further includes at least one third wiring layer located between the first wiring layer and the second wiring layer. The winding module further includes at least one fifth winding unit disposed in at least one of the third wiring layers. Each of the fifth winding units includes at least two fifth windings spaced apart and disposed in the third wiring layer. At least two of the fifth windings are connected in parallel with each other.

[0016] In some embodiments, the line widths of at least two of the fifth windings increase along the width direction of the body portion and away from the middle leg of the magnetic core.

[0017] In a second aspect, an embodiment of the present invention provides a power supply device including the planar transformer as described above.

[0018] Compared with the prior art, an embodiment of the present invention provides a planar transformer and a power supply device. The planar transformer includes a magnetic core module and a winding module. The magnetic core module includes a first magnetic core and a second magnetic core disposed opposite to each other. The second magnetic core includes a body portion and a middle leg of the magnetic core. The middle leg of the magnetic core is disposed on a surface of the body portion facing the first magnetic core. The winding module is located between the body portion and the first magnetic core and sleeved on the middle leg of the magnetic core. The winding module includes a substrate and a first winding unit. The substrate includes a first wiring layer. The first wiring layer includes a first wiring area. The first winding unit includes at least two first windings spaced apart from each other in the first wiring area. At least two first windings are connected in parallel with each other. Therefore, in this embodiment, by dividing a winding unit with an overly wide wire diameter into multiple windings and then connecting at least two windings in parallel, it is possible to avoid an overly wide wire diameter of the winding unit, thereby reducing the influence of the skin effect and the proximity effect, reducing the AC loss of the planar transformer, reducing the efficiency of the planar transformer, reducing the eddy current loss of the planar transformer, avoiding an overly high temperature rise of the planar transformer, further improving the efficiency of the planar transformer, and improving the stability of the planar transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 A schematic circuit diagram of a power supply device provided by an embodiment of the present invention;

[0021] Figure 2 An exploded view of a planar transformer provided by an embodiment of the present invention;

[0022] Figure 3 An exploded view of a planar transformer provided by an embodiment of the present invention;

[0023] Figure 4 A schematic structural diagram of a winding module provided by an embodiment of the present invention;

[0024] Figure 5 A schematic structural diagram of a winding module provided by another embodiment of the present invention;

[0025] Figure 6 It is a schematic structural diagram of a winding module provided in the conventional technology;

[0026] Figure 7 It is a schematic diagram of the current density distribution of a winding module provided in the conventional technology;

[0027] Figure 8 It is a schematic diagram of the current density distribution of a winding module provided in an embodiment of the present invention;

[0028] Figure 9 It is a schematic diagram of the AC resistance simulation of a first winding unit provided in an embodiment of the present invention;

[0029] Figure 10 It is a schematic diagram of the AC resistance simulation of a second winding unit provided in an embodiment of the present invention;

[0030] Figure 11 It is a schematic diagram of the AC resistance simulation of a third winding unit provided in an embodiment of the present invention;

[0031] Figure 12 It is a schematic diagram of the AC resistance simulation of a fourth winding unit provided in an embodiment of the present invention;

[0032] Figure 13 It is a schematic diagram of the AC resistance simulation of a fifth winding unit provided in an embodiment of the present invention. Detailed implementation manners

[0033] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0034] It should be noted that if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, and all are within the protection scope of the present invention. In addition, although functional module division is performed in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from the module division in the device or the flowchart. Furthermore, the terms "first", "second", "third", etc. adopted by the present invention do not limit the data and execution order, but are only used to distinguish the same items or similar items with basically the same functions and effects.

[0035] Please refer to Figure 1, an embodiment of the present invention provides a power supply device. The power supply device 1000 includes a DC power supply VDC, a planar transformer 100, a controller 200, a first switching transistor Q1, a second switching transistor Q2, a resonant inductor Lr, an exciting inductor Lm, a resonant capacitor Cr, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, a first output capacitor Co1, a second output capacitor Co2, and a third output capacitor Co3. The planar transformer 100 includes a primary winding 22, a first secondary winding 23, a second secondary winding 24, and a third secondary winding 25. The first secondary winding 23 includes a first winding unit 231 and a second winding unit 232. The second secondary winding 24 includes a third winding unit 241 and a fourth winding unit 242.

[0036] The positive pole of the DC power supply VDC is electrically connected to the drain of the first switching transistor Q1. The source of the first switching transistor Q1 is electrically connected to the drain of the second switching transistor Q2 and one end of the resonant inductor Lr respectively. The gates of the first switching transistor Q1 and the second switching transistor Q2 are electrically connected to the controller 200. The source of the second switching transistor Q2 and one end of the resonant capacitor Cr are electrically connected to the negative pole of the DC power supply VDC. The other end of the resonant inductor Lr is electrically connected to one end of the exciting inductor Lm and the same-named end of the primary winding 22 respectively. The other end of the exciting inductor Lm is electrically connected to the different-named end of the primary winding 22 and the other end of the resonant capacitor Cr respectively. The different-named end of the first winding unit 231 is electrically connected to the anode of the first diode D1. The cathode of the first diode D1 is electrically connected to the cathode of the second diode D2, one end of the first output capacitor Co1, and one end of the first load Ro1 respectively. The same-named end of the first winding unit 231 is electrically connected to the different-named end of the second winding unit 232, the other end of the first output capacitor Co1, and the other end of the first load Ro1 respectively. The different-named end of the third winding unit 241 is electrically connected to the anode of the third diode D3. The cathode of the third diode D3 is electrically connected to the cathode of the fourth diode D4, one end of the second output capacitor Co2, and one end of the second load Ro2 respectively. The same-named end of the third winding unit 241 is electrically connected to the different-named end of the fourth winding unit 242, the other end of the second output capacitor Co2, and the other end of the second load Ro2 respectively. The different-named end of the third secondary winding 25 is electrically connected to the anode of the fifth diode D5 and the cathode of the sixth diode D6 respectively. The cathode of the fifth diode D5 is electrically connected to the cathode of the seventh diode D7, one end of the third output capacitor Co3, and one end of the third load Ro3 respectively. The same-named end of the third secondary winding 25 is electrically connected to the anode of the seventh diode D7 and the cathode of the eighth diode D8 respectively. The anode of the sixth diode D6 is electrically connected to the anode of the eighth diode D8, the other end of the third output capacitor Co3, and the other end of the third load Ro3 respectively.

[0037] The working principle of the power supply device 1000 is as follows: The controller 200 controls the first switching transistor Q1 and the second switching transistor Q2 to conduct alternately, so that the first switching transistor Q1 and the second switching transistor Q2 convert the voltage of the DC power supply VDC into a high-frequency square wave. Subsequently, the high-frequency square wave enters a resonant cavity composed of a resonant inductor Lr, an exciting inductor Lm, and a resonant capacitor Cr. The resonant cavity eliminates the harmonics of the high-frequency square wave and outputs a sine wave with a fundamental frequency. The sine wave couples energy to the first secondary winding 23, the second secondary winding 24, and the third secondary winding 25 through the primary winding np, so that the first secondary winding 23, the second secondary winding 24, and the third secondary winding 25 generate alternating current. The first diode D1 and the second diode D2 rectify the alternating current generated by the first secondary winding 23 and output a stable first DC voltage. The third diode D3 and the fourth diode D4 rectify the alternating current generated by the second secondary winding 24 and output a stable second DC voltage. The fifth diode D5, the sixth diode D6, the seventh diode D7, and the eighth diode D8 rectify the alternating current generated by the third secondary winding 25 and output a stable third DC voltage.

[0038] In some embodiments, the first DC voltage is the main output voltage, the second DC voltage is the auxiliary output voltage, and the third DC voltage is the backlight output voltage. It can be understood that since the main output voltage is generally relatively low, the number of turns of the first secondary winding 23 is relatively small, usually 1 to 3 turns. Since the auxiliary output voltage is also relatively low, the number of turns of the second secondary winding 24 is also relatively small, usually 1 to 2 times the number of turns of the first secondary winding 23. Since the backlight output voltage is generally relatively high, the number of turns of the third secondary winding 25 is relatively large, usually 5 to 20 times the number of turns of the first secondary winding 23.

[0039] Please refer to Figure 2 and Figure 3 , an embodiment of the present invention provides a planar transformer, as shown in Figure 2 or Figure 3 . The planar transformer 100 includes a magnetic core module 10 and a winding module 20.

[0040] The magnetic core module 10 includes a first magnetic core 11 and a second magnetic core 12 which are arranged oppositely, and the first magnetic core 11 and the second magnetic core 12 are covered. The first magnetic core 11 or the second magnetic core 12 is mainly made of a magnetic core body material. Among them, the magnetic core body material can include ferrite, silicon steel sheet, etc. The type of ferrite can be nickel-zinc ferrite, manganese-zinc ferrite, and nickel-zinc ferrite. Those skilled in the art can select a suitable magnetic core body material according to actual needs.

[0041] The magnetic core shape of the first magnetic core 11 or the second magnetic core 12 can be any shape such as E-shaped, I-shaped, etc. Those skilled in the art can select a suitable magnetic core shape according to actual needs.

[0042] The second magnetic core 12 includes a body portion 121, a magnetic core central column 122, a first magnetic core side column 123, and a second magnetic core side column 124. The body portion 121 is in a straight plate shape. The magnetic core central column 122 protrudes from the middle of the surface 121a of the body portion 121 facing the first magnetic core 11. The magnetic core central column 122 is integrally formed with the body portion 121. Among them, the cross-sectional shape of the magnetic core central column 122 can be any shape such as a circle or a square. The first magnetic core side column 123 protrudes from the first side of the surface 121a, and the second magnetic core side column 124 protrudes from the second side of the surface 121a. The first side and the second side are opposite to each other. In some embodiments, the height of the first magnetic core side column 123 is the same as that of the second magnetic core side column 124 and is slightly higher than the height of the magnetic core central column 122. When the first magnetic core 11 and the second magnetic core 12 are covered, the first magnetic core side column 123 and the second magnetic core side column 124 are in contact with the first magnetic core 11, and there is a certain space between the magnetic core central column 122 and the first magnetic core 11. Please refer to Figure 4 , and this space is the air gap 10a. The function of the air gap 10a is to reduce the magnetic permeability, so that the line wounding characteristics are less dependent on the initial magnetic permeability of the magnetic core material. The air gap 10a can also avoid the magnetic saturation phenomenon under large AC signals or DC bias, and better control the inductance.

[0043] The winding module 20 is located between the body portion 121 and the first magnetic core 11. The winding module 20 is provided with a through hole corresponding to the magnetic core central column 122. The magnetic core central column 122 passes through the through hole, and the winding module 20 is sleeved on the magnetic core central column 122 through the through hole.

[0044] Please refer to Figure 1 and Figure 4 , Figure 4 For taking Figure 3 the right part of the thick dashed line shown and longitudinally cutting the planar transformer 100 through the thick solid line to obtain a cross-sectional schematic diagram. As Figure 1 and Figure 4 shown, the winding module 20 includes a substrate 21, a primary winding 22, a first secondary winding 23, a second secondary winding 24, and a third secondary winding 25.

[0045] The substrate 21 is the basic material for arranging the primary winding 22, the first secondary winding 23, the second secondary winding 24, and the third secondary winding 25. Generally, the substrate 21 can be a copper-clad laminate. During the process of manufacturing the winding module 20, through selective processing such as opening holes, electroless copper plating, electroplating copper, and etching on the substrate 21, and then arranging the primary winding 22, the first secondary winding 23, the second secondary winding 24, and the third secondary winding 25 on the substrate 21, the winding module 20 can be obtained.

[0046] As Figure 4As shown, the substrate 21 includes a first wiring layer 211, a second wiring layer 212, at least one third wiring layer 213 ( Figure 4 as shown in Figure 4 , the number of the third wiring layers 213 is 4), a fourth wiring layer 214, and a fifth wiring layer 215. The first wiring layer 211 is disposed on one side of the substrate 21 close to the air gap 10a (it should be noted that the side close to the air gap 10a refers to a certain area or certain areas that are closest to the air gap 10a along the axial direction of the substrate 21), and the second wiring layer 212 is disposed on the other side of the substrate 21 away from the air gap 10a (it should be noted that the other side away from the air gap 10a refers to a certain area or certain areas that are away from the air gap 10a relative to the first wiring layer 211 along the axial direction of the substrate 21).

[0047] The first wiring layer 211 includes a first wiring area 2111 and a second wiring area 2112. The second wiring area 2112 is disposed closer to the middle leg 122 of the magnetic core than the first wiring area 2111. The first wiring area 2111 is used for arranging the first winding unit 231, and the second wiring area 2112 is used for arranging the third winding unit 241.

[0048] The second wiring layer 212 includes a third wiring area 2121 and a fourth wiring area 2122. The third wiring area 2121 is disposed corresponding to the first wiring area 2111 and is used for arranging the second winding unit 232, and the fourth wiring area 2122 is disposed corresponding to the second wiring area 2112 and is used for arranging the fourth winding unit 242.

[0049] Since the first wiring layer 211 is closer to the air gap 10a than the second wiring layer 212, in this embodiment, by arranging a part of the windings of the first secondary winding 23 and a part of the windings of the second secondary winding 24 on the first wiring layer 211, and arranging another part of the windings of the first secondary winding 23 and another part of the windings of the second secondary winding 24 on the second wiring layer 212, the influence of the air gap 10a on the first secondary winding 23 and the second secondary winding 24 can be balanced, thereby improving the performance of the planar transformer 100.

[0050] The first winding unit 231 includes at least two first windings 2311 spaced apart and arranged in the first wiring area 2111. At least two first windings 2311 are connected in parallel. Please refer to Figure 5The direction indicated by the dotted arrow represents the direction along the width direction of the main body and away from the magnetic core center column 122. The first winding 2311_1, the first winding 2311_2, the first winding 2311_3, the first winding 2311_4 and the first winding 2311_5 are sequentially arranged along this direction in the first wiring area 2111. The first winding 2311_1 can be connected in parallel with the first winding 2311_2 to obtain a parallel winding, and the parallel winding, the first winding 2311_3, the first winding 2311_4 and the first winding 2311_5 are further connected in series; or the first winding 2311_1 , the first winding 2311_2, and the first winding 2311_3 are connected in parallel to obtain a parallel winding, and then the parallel winding, the first winding 2311_4, and the first winding 2311_5 are connected in series; or the first winding 2311_2 and the first winding 2311_3 are connected in parallel to obtain a parallel winding, and then the first winding 2311_1, the parallel winding, the first winding 2311_4, and the first winding 2311_5 are connected in series; or the first winding 2311_1, the first winding 2311_2, the first winding 2311_3, the first winding 2311_4, and the first winding 2311_5 are connected in parallel. It can be understood that if a winding unit includes only two windings, the two windings are connected in parallel. If a winding unit includes more than two windings, the windings can be connected in parallel, or two or more windings can be connected in parallel, and the parallel windings obtained after parallel connection can be connected in series with the remaining windings.

[0051] In some embodiments, the line width of each first winding is within a preset width range.

[0052] In some embodiments, the preset width range is (0.15 mm, 0.55 mm), where mm is millimeter.

[0053] In some embodiments, an isolation region is provided between two adjacent first windings 2311 . The isolation region may be a region that is grooved or filled with insulating material. The form of the isolation region is not limited here, as long as the isolation region can achieve insulation between the two adjacent first windings 2311 .

[0054] See also Figure 6 In conventional technology, the line width of the first winding unit 231 is relatively large. However, in this embodiment, by dividing the first winding unit 231 into at least two first windings 2311, the line width of the first winding unit 231, which originally has a larger line width, can be shared, and the current flowing through each first winding 2311 is reduced relative to the current originally flowing through the first winding unit 231.

[0055] The skin effect loss and proximity effect loss of each coil turn are derived based on Maxwell's equations:

[0056]

[0057] Among them, P ac1 is the skin effect loss, ρ is the resistivity of the copper wire, W n is the width of the coil, N n is the number of turns of the copper foil coil of the coil, I n is the current flowing through the coil, K s1 is the skin effect coefficient, P ac2 is the skin effect loss, K s2 is the proximity effect coefficient, L n is the distance from the coil to the air gap 10a.

[0058] The skin effect loss refers to the AC loss caused by the skin effect. The skin effect is a phenomenon in which the current distribution inside a conductor is uneven when there is an alternating current or an alternating magnetic field in the conductor. The proximity effect loss refers to the AC loss caused by the proximity effect. The proximity effect is a phenomenon in which the alternating currents in the two conductors of a two-wire transmission line approach each other towards the adjacent conductor.

[0059] If the first winding unit 231 with an overly wide wire diameter is divided into at least two first windings 2311 and the at least two first windings 2311 are connected in parallel with each other, according to the above formula, for the skin effect loss, when the wire width of the coil is smaller and the current is larger, the skin effect loss is larger. Although the wire width of each first winding 2311 is relatively reduced compared to the original wire width, the current is also relatively reduced. Therefore, the skin effect loss will not increase. For the proximity effect loss, when the wire width of the coil is larger and the current is larger, the proximity effect loss is smaller. Therefore, by dividing the first winding unit 231 with an overly wide wire diameter into at least two first windings 2311, the proximity effect loss can be reduced, thereby reducing the AC loss of the planar transformer 100.

[0060] It can be understood that when the wire diameter of the winding is overly wide, if a high-frequency current flows through the winding, a serious skin effect will occur. At this time, the high-frequency current will be concentrated in a certain area, resulting in an uneven current density distribution of the high-frequency current. Some current densities are very large, and some current densities are very small. The part of the space with a very small current density is wasted. Therefore, by dividing the first winding unit 231 with an overly wide wire diameter into at least two first windings 2311, the influence of the skin effect can be weakened, making the current density distribution more uniform, thereby reducing the wasted wiring space and further improving the utilization rate of the substrate 21.

[0061] It can also be understood that, according to Faraday's law of electromagnetic induction, the magnetic induction of electricity is proportional to the cross-sectional area of the closed conductor. The larger the cross-sectional area, the larger the eddy current generated. Therefore, by dividing the first winding unit 231 with an overly wide wire diameter into at least two first windings 2311, the cross-sectional area of the winding of the first winding unit 231 can be reduced, thereby reducing the eddy current, reducing the eddy current loss, avoiding excessive temperature rise and heat generation of the planar transformer 100, and improving the stability of the device.

[0062] Therefore, in this embodiment, by dividing the first winding unit 231 with an overly wide wire diameter into at least two first windings 2311 and then connecting the at least two first windings 2311 in parallel, it is possible to avoid an overly wide wire diameter of the first winding unit 231, thereby weakening the influence of the skin effect and the proximity effect, reducing the AC loss of the planar transformer 100, reducing the efficiency of the planar transformer 100, reducing the eddy current loss of the planar transformer 100, avoiding excessive temperature rise of the planar transformer 100, and further improving the efficiency of the planar transformer 100 and the stability of the planar transformer 100.

[0063] In some embodiments, as Figure 5 shown, along the width direction of the body portion 121 ( Figure 5 the direction of the dotted line shown), the wire width of the first winding 2311 closest to the middle leg 122 of the magnetic core is smaller than the wire width of the first winding 2311 farthest from the middle leg 122 of the magnetic core. Since the first winding 2311_1 is along the width direction of the body portion 121 and closest to the middle leg 122 of the magnetic core, and the first winding 2311_5 is along the width direction of the body portion 121 and farthest from the middle leg 122 of the magnetic core, therefore, the wire width of the first winding 2311_1 is smaller than the wire width of the first winding 2311_5.

[0064] It can be understood that the first winding 2311 closest to the middle leg 122 of the magnetic core along the width direction of the body portion 121 is closest to the air gap 10a, and the first winding 2311 farthest from the middle leg 122 of the magnetic core along the width direction of the body portion 121 is farthest from the air gap 10a. Therefore, by setting the wire width of the first winding 2311 closest to the middle leg 122 of the magnetic core along the width direction of the body portion 121 to be smaller than the wire width of the first winding 2311 farthest from the middle leg 122 of the magnetic core along the width direction of the body portion 121, it is beneficial to weaken the influence of the air gap 10a on each first winding 2311, thereby reducing the AC loss of the first winding unit 231 and further improving the efficiency of the planar transformer 100.

[0065] In some embodiments, the wire widths of at least two first windings 2311 increase along the width direction of the body portion 121 and away from the middle leg 122 of the magnetic core. That is, among the at least two first windings 2311, the wire widths of all the first windings 2311 may increase along the width direction of the body portion 121 and away from the middle leg 122 of the magnetic core, or the wire widths of some of the first windings 2311 may increase along the width direction of the body portion 121 and away from the middle leg 122 of the magnetic core. For example, as Figure 5 shown, the wire widths of the first winding 2311_1, the first winding 2311_2, the first winding 2311_3, the first winding 2311_4, and the first winding 2311_5 are 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, and 0.4 mm in sequence, or are 0.2 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.4 mm in sequence, or are 0.2 mm, 0.3 mm, 0.3 mm, 0.3 mm, and 0.4 mm in sequence.

[0066] Therefore, by setting the wire widths of at least two first windings 2311 to increase along the width direction of the body portion 121 and away from the middle leg 122 of the magnetic core, it is beneficial to further weaken the influence of the air gap 10a on each first winding 2311, thereby being beneficial to further reducing the AC loss of the first winding unit 231, and further being beneficial to further improving the efficiency of the planar transformer 100. Moreover, this setting method can make the current density distribution flowing through each first winding 2311 more uniform.

[0067] Please refer to Figure 7 and Figure 8 , Figure 7 which is a schematic diagram of the current density distribution of a planar transformer in the prior art, Figure 8 and Figure 7 is a schematic diagram of the current density distribution of a planar transformer provided in this embodiment. As Figure 8 shown, in the first winding unit 231, the current density in some regions is very small, while the current density in some regions is very large, and the current density distribution is very uneven. In this embodiment, as Figure 8 shown, there is no phenomenon that each first winding 2311 has both a high current density and a low current density. Therefore, compared with the prior art, the current distribution density of each first winding 2311 is more uniform.

[0068] The second winding unit 232 includes at least two second windings 2321 arranged at intervals in the third wiring area 2121. The at least two second windings 2321 are connected in parallel to each other. For the way of connecting the at least two second windings 2321 in parallel with each other, please refer to the above embodiments and will not be elaborated here.

[0069] Therefore, in this embodiment, by dividing the second winding unit 232 with an overly wide wire diameter into at least two second windings 2321 and then connecting the at least two second windings 2321 in parallel, it is possible to avoid the overly wide wire diameter of the second winding unit 232, thereby weakening the effects of the skin effect and the proximity effect, reducing the AC loss of the planar transformer 100, thus reducing the efficiency of the planar transformer 100, and reducing the eddy current loss of the planar transformer 100, thereby avoiding excessive temperature rise of the planar transformer 100, and further improving the efficiency of the planar transformer 100 and the stability of the planar transformer 100.

[0070] Each of the second windings 2321 is arranged corresponding to each of the first windings 2311 along the extending direction of the middle column 122 of the magnetic core. As Figure 5 shown, in the third wiring area 2121, the second windings 2321_1, 2321_2, 2321_3, 2321_4, and 2321_5 are sequentially arranged at intervals along the direction indicated by the dotted arrow. The extending direction along the middle column 122 of the magnetic core refers to Figure 5 the direction indicated by the solid arrow. Along this direction, the second winding 2321_1 corresponds to the first winding 2311_1, the second winding 2321_2 corresponds to the first winding 2311_2, the second winding 2321_3 corresponds to the first winding 2311_3, the second winding 2321_4 corresponds to the first winding 2311_4, and the second winding 2321_5 corresponds to the first winding 2311_5.

[0071] In some embodiments, the wire widths of the corresponding windings are equal. For example, as Figure 5 shown, the wire width of the second winding 2321_1 is equal to the wire width of the first winding 2311_1, the wire width of the second winding 2321_2 is equal to the wire width of the first winding 2311_2, the wire width of the second winding 2321_3 is equal to the wire width of the first winding 2311_3, the wire width of the second winding 2321_4 is equal to the wire width of the first winding 2311_4, and the wire width of the second winding 2321_5 is equal to the wire width of the first winding 2311_5.

[0072] In some embodiments, the wire width of each second winding 2321 is within a preset width range. The preset width range can refer to the above embodiments and will not be elaborated here.

[0073] In some embodiments, an isolation area is provided between two adjacent second windings 2321. The isolation area can be an area with slots or filled with insulating materials. The form of the isolation area is not limited here as long as the isolation area can achieve insulation between two adjacent second windings 2321.

[0074] In some embodiments, as Figure 5As shown, the line width of the second winding 2321 along the width direction of the body portion 121 and closest to the core middle leg 122 is smaller than the line width of the second winding 2321 along the width direction of the body portion 121 and farthest from the core middle leg 122.

[0075] Therefore, by setting the line width of the second winding 2321 along the width direction of the body portion 121 and closest to the core middle leg 122 to be smaller than the line width of the first winding 2311 along the width direction of the body portion 121 and farthest from the core middle leg 122, it is beneficial to weaken the influence of the air gap 10a on each second winding 2321, thereby being beneficial to reducing the AC loss of the second winding unit 232, and further being beneficial to improving the efficiency of the planar transformer 100.

[0076] In some embodiments, as Figure 5 shown, the line widths of at least two second windings 2321 increase along the width direction of the body portion 121 and away from the core middle leg 122. The increasing manner of the line widths of at least two second windings 2321 can refer to the above embodiments and will not be elaborated here.

[0077] Therefore, by setting the line widths of at least two second windings 2321 to increase along the width direction of the body portion 121 and away from the core middle leg 122, it is beneficial to further weaken the influence of the air gap 10a on each second winding 2321, thereby being beneficial to further reducing the AC loss of the second winding unit 232, and further being beneficial to further improving the efficiency of the planar transformer 100. Moreover, this setting method can make the current density distribution flowing through each second winding 2321 more uniform.

[0078] As Figure 7 shown, in the traditional technology, the current density in a part of the region in the second winding unit 232 is very small, while the current density in a part of the region is very large, and the current density distribution is very uneven. In this embodiment, as Figure 8 shown, there is no phenomenon that each second winding 2321 has both a high current density and a low current density. Therefore, compared with the traditional technology, the current distribution density of each second winding 2321 is more uniform.

[0079] The third winding unit 241 includes at least two third windings 2411 spacedly arranged in the second wiring area 2112. At least two third windings 2411 are connected in parallel with each other. The parallel connection manner of at least two third windings 2411 can refer to the above embodiments and will not be elaborated here.

[0080] Therefore, in this embodiment, the third winding unit 241 with an overly wide wire diameter is divided into at least two third windings 2411, and then the at least two third windings 2411 are connected in parallel. In this way, the wire diameter of the third winding unit 241 can be prevented from being overly wide, thereby weakening the influence of the skin effect and proximity effect, reducing the AC loss of the planar transformer 100, thus reducing the efficiency of the planar transformer 100, and reducing the eddy current loss of the planar transformer 100, thereby avoiding excessive temperature rise of the planar transformer 100, and further improving the efficiency of the planar transformer 100 and the stability of the planar transformer 100.

[0081] In some embodiments, the wire width of each third winding is within a preset width range. The preset width range can refer to the above embodiments and will not be elaborated here.

[0082] In some embodiments, an isolation area is provided between two adjacent third windings 2411. The isolation area can be an area with slots or filled with insulating materials. The form of the isolation area is not limited here as long as the isolation area can achieve insulation between two adjacent third windings 2411.

[0083] In some embodiments, as Figure 5 shown, the wire width of the third winding 2411 along the width direction of the body part 121 and closest to the middle leg 122 of the magnetic core is smaller than the wire width of the third winding 2411 along the width direction of the body part 121 and farthest from the middle leg 122 of the magnetic core.

[0084] Therefore, by setting the wire width of the third winding 2411 along the width direction of the body part 121 and closest to the middle leg 122 of the magnetic core to be smaller than the wire width of the third winding 2411 along the width direction of the body part 121 and farthest from the middle leg 122 of the magnetic core, it is beneficial to weaken the influence of the air gap 10a on each third winding 2411, thereby being beneficial to reducing the AC loss of the third winding unit 241, and further being beneficial to improving the efficiency of the planar transformer 100.

[0085] In some embodiments, as Figure 5 shown, the wire widths of at least two third windings 2411 increase along the width direction of the body part 121 and away from the middle leg 122 of the magnetic core. The increasing manner of the wire widths of at least two third windings 2411 can refer to the above embodiments and will not be elaborated here.

[0086] Therefore, by setting the wire widths of at least two third windings 2411 to increase along the width direction of the body part 121 and away from the middle leg 122 of the magnetic core, it is beneficial to further weaken the influence of the air gap 10a on each third winding 2411, thereby being beneficial to further reducing the AC loss of the third winding unit 241, and further beneficial to improving the efficiency of the planar transformer 100. Moreover, this setting method can make the current density distribution of each third winding 2411 more uniform.

[0087] As Figure 7 shown, in the traditional technology, the current density in a part of the third winding unit 241 is very small, while the current density in another part is very large, and the current density distribution is very uneven. In this embodiment, as Figure 8 shown, there is no phenomenon of both high and low current density in each third winding 2411. Therefore, compared with the traditional technology, the current distribution density of each third winding 2411 is more uniform.

[0088] The fourth winding unit 242 includes at least two fourth windings 2421 arranged at intervals in the fourth wiring area 2122. At least two fourth windings 2421 are connected in parallel. For the way of connecting at least two fourth windings 2421 in parallel, please refer to the above embodiment and will not be elaborated here.

[0089] Therefore, in this embodiment, by dividing the fourth winding unit 242 with an overly wide wire diameter into at least two fourth windings 2421 and then connecting at least two fourth windings 2421 in parallel, it is possible to avoid the overly wide wire diameter of the fourth winding unit 242, thereby weakening the influence of the skin effect and proximity effect, reducing the AC loss of the planar transformer 100, thus reducing the efficiency of the planar transformer 100, and reducing the eddy current loss of the planar transformer 100, thereby avoiding excessive temperature rise of the planar transformer 100, and further being able to improve the efficiency of the planar transformer 100 and the stability of the planar transformer 100.

[0090] Each fourth winding 2421 and each of the third windings 2411 are arranged in one-to-one correspondence along the extending direction of the middle leg 122 of the magnetic core. As Figure 5 shown, in the second wiring area 2112, the third windings 2411_1, 2411_2, 2411_3, 2411_4 and the second winding 2411_5 are arranged at intervals in sequence along the direction indicated by the thin dashed arrow. In the fourth wiring area 2122, the fourth windings 2421_1, 2411_2, 2411_3, 2411_4 and the fourth winding 2411_5 are arranged at intervals in sequence along the direction indicated by the thin dashed arrow. The extending direction along the middle leg 122 of the magnetic core refers to Figure 5The direction indicated by the medium thick solid arrow. Along this direction, the fourth winding 2421_1 corresponds to the third winding 2411_1, the fourth winding 2421_2 corresponds to the third winding 2411_2, and the fourth winding 2421_3 corresponds to the third winding 2411_3.

[0091] In some embodiments, the wire widths of the correspondingly arranged windings are equal. For example, as Figure 5 shown, the wire width of the fourth winding 2421_1 is equal to the wire width of the third winding 2411_1, the wire width of the fourth winding 2421_2 is equal to the wire width of the third winding 2411_2, and the wire width of the fourth winding 2421_3 is equal to the wire width of the third winding 2411_3.

[0092] In some embodiments, the wire width of each fourth winding is within a preset width range. The preset width range can refer to the above embodiments and will not be elaborated here.

[0093] In some embodiments, an isolation area is provided between two adjacent fourth windings 2421. The isolation area can be an area with slots or filled with insulating materials. The form of the isolation area is not limited here as long as the isolation area can achieve insulation between two adjacent fourth windings 2421.

[0094] In some embodiments, as Figure 5 shown, the wire width of the fourth winding 2421 along the width direction of the body part 121 and closest to the middle leg 122 of the magnetic core is smaller than the wire width of the fourth winding 2421 along the width direction of the body part 121 and farthest from the middle leg 122 of the magnetic core.

[0095] Therefore, by setting the wire width of the fourth winding 2421 along the width direction of the body part 121 and closest to the middle leg 122 of the magnetic core to be smaller than the wire width of the fourth winding 2421 along the width direction of the body part 121 and farthest from the middle leg 122 of the magnetic core, it is beneficial to weaken the influence of the air gap 10a on each fourth winding 2421, thereby being beneficial to reducing the AC loss of the fourth winding unit 242, and further being beneficial to improving the efficiency of the planar transformer 100.

[0096] In some embodiments, as Figure 5 shown, the wire widths of at least two fourth windings 2421 increase along the width direction of the body part 121 and away from the middle leg 122 of the magnetic core. The increasing manner of the wire widths of at least two fourth windings 2421 can refer to the above embodiments and will not be elaborated here.

[0097] Therefore, by setting the wire widths of at least two fourth windings 2421 to increase along the width direction of the body portion 121 and away from the middle leg 122 of the magnetic core, it is beneficial to further weaken the influence of the air gap 10a on each fourth winding 2421, thereby being beneficial to further reduce the AC loss of the fourth winding unit 242, and further being beneficial to improve the efficiency of the planar transformer 100. Moreover, this setting method can make the current density distribution flowing through each fourth winding 2421 more uniform.

[0098] As Figure 7 shown, in the traditional technology, the current density in a part of the area in the fourth winding unit 242 is very small, while the current density in a part of the area is very large, and the current density distribution is very uneven. In this embodiment, as Figure 8 shown, for each fourth winding 2421, there is no phenomenon of both high current density and low current density. Therefore, compared with the traditional technology, the current distribution density of each fourth winding 2421 is more uniform.

[0099] The primary winding 22 includes at least one fifth winding unit 221. At least one fifth winding unit 221 is disposed on at least one third wiring layer 213. Each fifth winding unit 221 includes at least two fifth windings 2211 spaced apart on one third wiring layer 213, and at least two fifth windings 2211 are connected in parallel with each other.

[0100] For the way that at least two fifth windings 2211 are connected in parallel with each other, please refer to the above-mentioned embodiment, and details will not be described here.

[0101] Therefore, in this embodiment, by dividing the fifth winding unit 221 with an overly wide wire diameter into at least two fifth windings 2211 and then connecting at least two fifth windings 2211 in parallel, it is possible to avoid the overly wide wire diameter of the fifth winding unit 221, thereby being able to weaken the influence of the skin effect and the proximity effect, reduce the AC loss of the planar transformer 100, thereby reducing the efficiency of the planar transformer 100, and reducing the eddy current loss of the planar transformer 100, thereby avoiding the overheating of the planar transformer 100. Furthermore, it is possible to further improve the efficiency of the planar transformer 100 and improve the stability of the planar transformer 100.

[0102] In some embodiments, the wire width of each fifth winding 2211 is within a preset width range. The preset width range can refer to the above-mentioned embodiment, and details will not be described here.

[0103] In some embodiments, an isolation area is provided between two adjacent fifth windings 2211. The isolation area can be an area with slots or filled with insulating materials. The form of the isolation area is not limited here, as long as the isolation area can achieve insulation between two adjacent fifth windings 2211.

[0104] In some embodiments, as Figure 5 shown, the line width of the fifth winding 2211 along the width direction of the body portion 121 and closest to the middle leg 122 of the magnetic core is smaller than the line width of the fifth winding 2211 along the width direction of the body portion 121 and farthest from the middle leg 122 of the magnetic core.

[0105] Therefore, by setting the line width of the fifth winding 2211 along the width direction of the body portion 121 and closest to the middle leg 122 of the magnetic core to be smaller than the line width of the fifth winding 2211 along the width direction of the body portion 121 and farthest from the middle leg 122 of the magnetic core, it is beneficial to weaken the influence of the air gap 10a on each fifth winding 2211, thereby being beneficial to reducing the AC loss of the fifth winding unit 221, and further being beneficial to improving the efficiency of the planar transformer 100.

[0106] In some embodiments, as Figure 5 shown, the line widths of at least two fifth windings 2211 increase along the width direction of the body portion 121 and away from the middle leg 122 of the magnetic core. The increasing manner of the line widths of at least two fifth windings 2211 may refer to the above embodiments and will not be elaborated here.

[0107] Therefore, by setting the line widths of at least two fifth windings 2211 to increase along the width direction of the body portion 121 and away from the middle leg 122 of the magnetic core, it is beneficial to further weaken the influence of the air gap 10a on each fifth winding 2211, thereby being beneficial to further reducing the AC loss of the fifth winding unit 221, and further being beneficial to further improving the efficiency of the planar transformer 100. Moreover, this setting method can make the current density distribution flowing through each fifth winding 2211 more uniform.

[0108] As Figure 7 shown, in the traditional technology, the current density in a part of the region in the fifth winding unit 221 is very small, while the current density in a part of the region is very large, and the current density distribution is very uneven. However, in this embodiment, as Figure 8 shown, each fifth winding 2211 does not show the phenomenon of both high current density and low current density. Therefore, compared with the traditional technology, the current distribution density of each fifth winding 2211 is more uniform.

[0109] As Figure 4 shown, the third secondary winding 25 includes a plurality of sixth windings 251, a plurality of seventh windings 252, and at least one eighth winding 253.

[0110] The plurality of sixth windings 251 are arranged at intervals on the fourth wiring layer 214.

[0111] The plurality of seventh windings 252 are arranged at intervals on the fifth wiring layer 215.

[0112] At least one eighth winding 253 is disposed on the third wiring layer 213.

[0113] It can be understood that by connecting multiple sixth windings 251 in series, a first series winding can be obtained. By connecting multiple seventh windings 252 in series, a second series winding can be obtained. By connecting the first series winding, the second series winding, and at least one eighth winding 253 in series, a third secondary winding 25 can be obtained.

[0114] The following describes the comparison of the AC resistance between this embodiment and the traditional solution in combination with the simulation results.

[0115] Figure 9 It is a schematic diagram of the AC resistance simulation of a first winding unit provided by an embodiment of the present invention. As Figure 9 shown, curve 1 is the AC resistance change curve when the first winding unit is not divided in the traditional solution, and curve 2 is the AC resistance change curve of the first winding unit in this embodiment. By comparing curve 1 and curve 2, it can be seen that in the full frequency range, the AC resistance of the first winding unit in this embodiment is significantly smaller than that of the first winding unit in the traditional solution by about 10% - 50%.

[0116] Figure 10 It is a schematic diagram of the AC resistance simulation of a second winding unit provided by an embodiment of the present invention. As Figure 10 shown, curve 3 is the AC resistance change curve when the second winding unit is not divided in the traditional solution, and curve 4 is the AC resistance change curve of the second winding unit in this embodiment. By comparing curve 3 and curve 4, it can be seen that in the full frequency range, the AC resistance of the second winding unit in this embodiment is significantly smaller than that of the second winding unit in the traditional solution by about 10% - 50%.

[0117] Figure 11 It is a schematic diagram of the AC resistance simulation of a third winding unit provided by an embodiment of the present invention. As Figure 11 shown, curve 5 is the AC resistance change curve when the third winding unit is not divided in the traditional solution, and curve 6 is the AC resistance change curve of the second winding unit in this embodiment. By comparing curve 5 and curve 6, it can be seen that in the full frequency range, the AC resistance of the third winding unit in this embodiment is significantly smaller than that of the third winding unit in the traditional solution by about 10% - 50%.

[0118] Figure 12 It is a schematic diagram of the AC resistance simulation of a fourth winding unit provided by an embodiment of the present invention. As Figure 12As shown, curve 7 is the AC resistance variation curve of the fourth winding unit without segmentation in the traditional solution, and curve 8 is the AC resistance variation curve of the fourth winding unit in this embodiment. By comparing curve 7 and curve 8, it can be seen that within the full frequency range, the AC resistance of the fourth winding unit in this embodiment is significantly smaller than that of the fourth winding unit in the traditional solution by about 10% - 50%.

[0119] Figure 13 This is a schematic diagram of the AC resistance simulation of a fifth winding unit provided by an embodiment of the present invention. As Figure 13 shown, curve 9 is the AC resistance variation curve of the fifth winding unit without segmentation in the traditional solution, and curve 10 is the AC resistance variation curve of the fifth winding unit in this embodiment. By comparing curve 9 and curve 10, it can be seen that when the frequency is between 100 kHz and 500 kHz, the AC resistance of this embodiment is significantly smaller than that of the traditional solution. Above 500 kHz, the AC resistance of this embodiment will be greater than that of the traditional solution. However, for most current applications, the operating frequency is less than 150 kHz, and more than 90% of the high-frequency losses are less than 500 kHz. Therefore, the fifth winding unit of this embodiment also has great advantages.

[0120] Finally, it should be noted that the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments do not serve as additional limitations to the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosed content of the present invention more thorough and comprehensive. And under the idea of the present invention, the above technical features continue to be combined with each other, and there are many other variations in different aspects of the present invention as described above, all of which are regarded as the scope described in the specification of the present invention. Further, for those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A planar transformer, characterized in that, Comprising: A core module, including a first core and a second core which are oppositely arranged. The second core includes a body part and a core middle column. The core middle column is arranged on a side of the body part facing the first core, and an air gap is formed by an interval between the core middle column and the first core. And A winding module, located between the body part and the first core and sleeved on the core middle column. The winding module includes a substrate, a first winding unit, a second winding unit, a third winding unit and a fourth winding unit. The substrate includes a first wiring layer and a second wiring layer. The first wiring layer is arranged on a side of the substrate close to the air gap, and the second wiring layer is arranged on a side of the substrate far from the air gap. The first wiring layer includes a first wiring area and a second wiring area. The second wiring area is arranged relatively closer to the core middle column than the first wiring area. The first winding unit includes at least two first windings arranged at intervals in the first wiring area, and the at least two first windings are connected in parallel with each other. The third winding unit is arranged in the second wiring area. The second wiring layer includes a third wiring area corresponding to the first wiring area and a fourth wiring area corresponding to the second wiring area. The second winding unit is arranged in the third wiring area, and the fourth winding unit is arranged in the fourth wiring area. The first winding unit and the second winding unit are connected in series to form a first secondary winding, and the third winding unit and the fourth winding unit are connected in series to form a second secondary winding.

2. The planar transformer according to claim 1, wherein, The wire widths of the at least two first windings increase along the width direction of the body part and away from the core middle column.

3. The planar transformer according to claim 1, characterized in that, The second winding unit includes at least two second windings arranged at intervals in the third wiring area, and the at least two second windings are connected in parallel with each other. Each of the second windings and each of the first windings are arranged in one-to-one correspondence along the extending direction of the core middle column.

4. The planar transformer according to claim 3, wherein The wire widths of the at least two second windings increase along the width direction of the body part and away from the core middle column.

5. The planar transformer according to claim 1, characterized in that, The third winding unit includes at least two third windings arranged at intervals in the second wiring area, and the at least two third windings are connected in parallel with each other.

6. The planar transformer according to claim 5, characterized in that, The fourth winding unit includes at least two fourth windings arranged at intervals in the fourth wiring area, and the at least two fourth windings are connected in parallel with each other. Each of the fourth windings and each of the third windings are arranged in one-to-one correspondence along the extending direction of the core middle column.

7. The planar transformer according to claim 6, wherein The wire widths of the at least two fourth windings or the at least two third windings increase along the width direction of the body part and away from the core middle column.

8. The planar transformer according to claim 1, wherein The substrate further includes at least one third wiring layer, and the third wiring layer is located between the first wiring layer and the second wiring layer. The winding module further includes at least one fifth winding unit, and at least one of the fifth winding units is arranged on at least one of the third wiring layers. Each of the fifth winding units includes at least two fifth windings arranged at intervals in the third wiring layer, and the at least two fifth windings are connected in parallel with each other.

9. The planar transformer according to claim 8, wherein The wire widths of the at least two fifth windings increase along the width direction of the body portion and away from the middle leg of the magnetic core.

10. A power supply device, characterized in that, Comprising a planar transformer according to any one of claims 1 to 9.

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