Planar transformer and power supply

Abstract

The embodiment of the utility model discloses a planar transformer and a power supply. The planar transformer comprises a printed circuit board, wherein a magnetic core area, a first synchronous rectification area, a second synchronous rectification area and a first power connection area are arranged on the printed circuit board; the magnetic core is arranged in the magnetic core area and is buckled with the printed circuit board; the winding is arranged on the printed circuit board; the primary side pin and the secondary side pin are arranged on the same side of the printed circuit board; the first synchronous rectification area and the second synchronous rectification area are used for arranging synchronous rectification devices, and the first power connection area is used for electrically connecting the first synchronous rectification area and the second synchronous rectification area; the first power connection area and the magnetic core area are arranged in the first direction, the first synchronous rectification area, the magnetic core area and the second synchronous rectification area are sequentially arranged in the second direction perpendicular to the first direction, the first direction is the same as the direction of an air channel in a power source where the planar transformer is located, and therefore the power source can have high heat dissipation efficiency.

Description

Technical Field

[0001] The present application relates to the field of electronic power technology, and in particular to a planar transformer and a power supply. Background Art

[0002] As the power density of server power supplies increases, high frequency becomes a trend in power converters. As an important component in the power supply, the transformer is gradually miniaturized in the high-frequency design of the power supply. However, in the process of miniaturization of the transformer, the heat dissipation of the power supply becomes an important problem in the miniaturization of the transformer. Therefore, how to make the power supply have efficient heat dissipation capability while miniaturizing the transformer is a technical problem that needs to be solved urgently. Utility Model Content

[0003] In view of the deficiencies in the prior art, the present application provides a planar transformer and a power supply, aiming to solve the technical problem in the prior art that the heat dissipation efficiency of the power supply is poor after the transformer of the power supply is miniaturized.

[0004] To this end, in a first aspect, the present application provides a planar transformer, comprising:

[0005] A printed circuit board, wherein a magnetic core region, a first synchronous rectification region, a second synchronous rectification region and a first power connection region are arranged on the printed circuit board;

[0006] A magnetic core, disposed in the magnetic core region and buckled with the printed circuit board;

[0007] The primary winding and the secondary winding are both arranged on the printed circuit board;

[0008] The primary side pins and the secondary side pins are both arranged on the same side of the printed circuit board;

[0009] Among them, the first synchronous rectification area and the second synchronous rectification area are used to set up synchronous rectification devices; the first power connection area is used to electrically connect the first synchronous rectification area and the second synchronous rectification area; on the printed circuit board, the first power connection area and the magnetic core area are arranged along a first direction, and the first synchronous rectification area, the magnetic core area and the second synchronous rectification area are arranged along a second direction in sequence, and the first direction is perpendicular to the second direction; the first direction is the same as the direction of the air duct in the power supply where the planar transformer is located.

[0010] Furthermore, in the planar transformer, the first synchronous rectification region and the second synchronous rectification region are provided with a synchronous rectification switch and a rectification filter capacitor of the power supply.

[0011] Furthermore, in the planar transformer, synchronous rectification driving circuits are further provided in the first synchronous rectification region and the second synchronous rectification region.

[0012] Furthermore, in the planar transformer, a second power connection area is also provided on the printed circuit board, and the second power connection area is used to electrically connect the first synchronous rectification area and the second synchronous rectification area.

[0013] Furthermore, in the planar transformer, on the printed circuit board, the first power connection area, the magnetic core area and the second power connection area are arranged in sequence along the first direction.

[0014] Furthermore, in the planar transformer, the first power connection area is provided with a synchronous rectification drive circuit and / or a rectification filter capacitor of the power supply; or / and

[0015] The second power connection area is provided with a synchronous rectification drive circuit and / or a rectification filter capacitor of the power supply.

[0016] Further, in the planar transformer, the planar transformer comprises a plurality of the printed circuit boards, and the magnetic core comprises an EI magnetic core;

[0017] The area between the middle column and the side column of the EI magnetic core corresponds to the area on the printed circuit board where the primary winding and the secondary winding are arranged.

[0018] Furthermore, in the planar transformer, the primary pin and the secondary pin are close to the first synchronous rectification region or close to the second synchronous rectification region along the second direction.

[0019] Furthermore, in the planar transformer, at least one of the primary pin and the secondary pin is vertically welded to a mainboard of the power supply.

[0020] Furthermore, in the planar transformer, a primary circuit of the power supply is electrically connected between the primary winding and the primary pin.

[0021] In a second aspect, the present application also provides a power supply, which includes:

[0022] The planar transformer according to the first aspect;

[0023] The housing has an air duct;

[0024] A fan, arranged on the inner side or the outer side of the housing;

[0025] Wherein, the planar transformer is arranged in the air duct, and the direction of the air duct is the same as the first direction.

[0026] The planar transformer provided by the present application includes a printed circuit board, a magnetic core buckled at the magnetic core area of ​​the printed circuit board, pins arranged on the same side of the printed circuit board, and a winding arranged on the printed circuit board. At the same time, the printed circuit board is also provided with a first synchronous rectification area, a second synchronous rectification area, and a first power connection area. The first power connection area and the magnetic core area are arranged along a first direction that is the same as the direction of the air duct in the power supply where the planar transformer is located. The first synchronous rectification area, the magnetic core area, and the second synchronous rectification area are arranged in turn along a second direction perpendicular to the first direction. The first synchronous rectification area and the second synchronous rectification area are used to set synchronous rectification devices, and the first power connection area is used to electrically connect the first synchronous rectification area and the second synchronous rectification area. The planar transformer provided by the present application is small in size. After being installed in a high-frequency power supply, the magnetic core of the planar transformer can avoid affecting the heat dissipation of the synchronous rectification device of the power supply, greatly improving the heat dissipation efficiency of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a diagram showing the position relationship between the magnetic core and the synchronous rectifier device in a traditional power supply;

[0029] Figure 2 The position relationship diagram of the magnetic core and the synchronous rectifier device after improving the traditional power supply;

[0030] Figure 3 A schematic diagram of the structure of a planar transformer provided in an embodiment of the present application;

[0031] Figure 4 A position relationship diagram of various areas on a printed circuit board provided in an embodiment of the present application;

[0032] Figure 5 A schematic diagram of the structure of a power supply provided in an embodiment of the present application;

[0033] Figure 6 A schematic diagram of the arrangement of components in a power supply provided in an embodiment of the present application;

[0034] Figure 7 A position relationship diagram of various areas on a printed circuit board provided in an embodiment of the present application;

[0035] Figure 8 This is another position relationship diagram of various areas on a printed circuit board provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0038] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0039] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0040] In the prior art, the layout design of the printed circuit board in the planar transformer has a great influence on the heat dissipation of the planar transformer, so Figure 1 However, Figure 1 The magnetic core of the power supply and the synchronous rectifier components of the synchronous rectifier module need to be arranged in the direction of the air duct, that is, the magnetic core and the synchronous rectifier components are in a front-to-back position in the direction of the air duct. Figure 1 The positional relationship shown will affect the heat dissipation of the synchronous rectifier device, resulting in poor heat dissipation efficiency of the power supply.

[0041] To this end, in the process of improving the heat dissipation efficiency of traditional power supplies, Figure 2The design is performed in the manner shown, that is, the magnetic core of the power supply and the synchronous rectifier devices of the synchronous rectifier module need to be arranged in the direction of the air duct in sequence, that is, the magnetic core and the synchronous rectifier devices are in a side-by-side position relationship in the direction of the air duct, and the magnetic core will not affect the heat dissipation of the synchronous rectifier devices. However, after the magnetic core and the synchronous rectifier devices are in a side-by-side position relationship in the direction of the air duct, all the synchronous rectifier devices in the synchronous rectifier module are concentrated on one side of the magnetic core, resulting in the heat dissipation efficiency of the power supply is still not very ideal.

[0042] In order to better improve the heat dissipation efficiency of the power supply, the present application can divide the synchronous rectification devices in the synchronous rectification module into two groups and place them on both sides of the magnetic core. At this time, the synchronous rectification devices in the synchronous rectification module and the magnetic core are in a side-by-side relationship in the direction of the air duct, thereby avoiding the heat dissipation of all the synchronous rectification devices in the synchronous rectification module from being affected, thereby greatly improving the heat dissipation efficiency of the power supply.

[0043] The following is a detailed description of the technical solution. Figure 3 and Figure 4 , Figure 3 A schematic diagram of the structure of a planar transformer provided in an embodiment of the present application; Figure 4 A diagram showing the positional relationship of various areas on a printed circuit board provided in an embodiment of the present application.

[0044] like Figure 3 and Figure 4 As shown, a planar transformer 70 includes:

[0045] A printed circuit board 71, on which a magnetic core region 400, a first synchronous rectification region 100, a second synchronous rectification region 200 and a first power connection region 300 are arranged;

[0046] The magnetic core 72 is disposed in the magnetic core area 400 and is engaged with the printed circuit board 71;

[0047] The primary winding and the secondary winding (not shown in the figure) are both arranged on a printed circuit board 71;

[0048] The primary pin 73 and the secondary pin 74 are both arranged on the same side of the printed circuit board 71;

[0049] Among them, the first synchronous rectification area 100 and the second synchronous rectification area 200 are used to set up synchronous rectification devices; the first power connection area 300 is used to electrically connect the first synchronous rectification area 100 and the second synchronous rectification area 200; on the printed circuit board 71, the first power connection area 300 and the magnetic core area 400 are arranged along the first direction, and the first synchronous rectification area 100, the magnetic core area 400 and the second synchronous rectification area 200 are arranged along the second direction in sequence, and the first direction is perpendicular to the second direction; the first direction is the same as the direction of the air duct in the power supply where the planar transformer is located.

[0050] Specifically, the copper layers on the printed circuit board 71 can be used as the primary winding and the secondary winding of the planar transformer 70 , and the first synchronous rectification region 100 and the second synchronous rectification region 200 of the planar transformer 70 are located on the printed circuit board 71 .

[0051] In this embodiment, after the planar transformer 70 is installed in the power supply, at least part of the synchronous rectification devices in the synchronous rectification module of the power supply can be arranged in the first synchronous rectification area 100 and the second synchronous rectification area 200 of the printed circuit board 71, and the synchronous rectification devices in the first synchronous rectification area 100 and the second synchronous rectification area 200 can be electrically connected at the first power connection area 300, and output the rectified DC power at the first power connection area 300.

[0052] That is to say, the first power connection area 300 is used to electrically connect the power and / or signal between the first synchronous rectification area 100 and the second synchronous rectification area 200, that is, the signals required by the synchronous rectification devices in the first synchronous rectification area 100 and the second synchronous rectification area 200 can be transmitted by the first power connection area 300, and at the same time, the DC power output by the synchronous rectification devices after synchronous rectification can also be output by the first power connection area 300.

[0053] In addition, the first direction needs to be consistent with the air duct direction of the power supply, thereby preventing the magnetic core 72 of the planar transformer 70 from affecting the heat dissipation of the synchronous rectifier device, thereby greatly improving the heat dissipation efficiency of the power supply.

[0054] In some embodiments, Figure 5 and Figure 6 As shown, the present application also provides a power supply, which includes:

[0055] The housing 10 has an air duct;

[0056] The fan 20 is disposed inside or outside the housing 10;

[0057] The planar transformer 70 is arranged in the air duct, and a magnetic core region 400, a first synchronous rectification region 100, a second synchronous rectification region 200 and a first power connection region 300 are arranged on the printed circuit board 71 of the planar transformer 70;

[0058] A synchronous rectification module, comprising synchronous rectification devices on a first synchronous rectification region 100 and a second synchronous rectification region 200 of a printed circuit board 71;

[0059] Among them, after the first power connection area 300 and the magnetic core area 400 on the printed circuit board 71 are arranged along the direction of the air duct, the first power connection area 300 and the magnetic core area 400 can be in a front-to-back positional relationship; after the first synchronous rectification area 100, the magnetic core area 400 and the second synchronous rectification area 200 on the printed circuit board 71 are arranged in sequence along the direction perpendicular to the air duct, the first synchronous rectification area 100 and the magnetic core area 400, as well as the magnetic core area 400 and the second synchronous rectification area 200 can be in an up-down positional relationship.

[0060] In this embodiment, the power supply adopts a high-frequency design, and the power supply adopts a planar transformer 70, so that the power supply has the characteristics of high frequency and miniaturization. At the same time, in order to improve the heat dissipation efficiency of the synchronous rectification module of the power supply, the first synchronous rectification area 100, the second synchronous rectification area 200 and the first power connection area 300 are arranged on the planar transformer 70, and the first synchronous rectification area 100, the magnetic core area 400 and the second synchronous rectification area 200 are arranged in sequence along the direction perpendicular to the air duct, that is, all the heat-generating devices in the synchronous rectification module, that is, the synchronous rectification devices, can be placed side by side with the magnetic core at the magnetic core area 400 in the direction of the air duct to improve the heat dissipation efficiency. At the same time, some non-heat-generating devices in the synchronous rectification module are arranged in the first power connection area 300, so as to ensure that the synchronous rectification devices between the first synchronous rectification area 100 and the second synchronous rectification area 200 can achieve synchronous rectification.

[0061] Specifically, the power supply provided in the present application includes a housing 10, a fan 20, an input connector 30, a PFC module, an LLC module, a bus capacitor 60, a planar transformer 70, a synchronous rectification module, an output capacitor 80 and a mainboard. The PFC module includes a PFC inductor 41 and a PFC circuit board 42, wherein the PFC circuit board 42 is provided with a power device. The LLC module includes an inductor core 51 and an LLC circuit board 52, wherein the LLC circuit board 52 is also provided with a power device. The mainboard is arranged in the housing 10, and the PFC inductor 41, the PFC circuit board 42, the inductor core 51 and the LLC circuit board 52, the bus capacitor 60, the planar transformer 70, the output capacitor 80, the input connector 30, and the bus capacitor 60 are all electrically connected to the mainboard.

[0062] Furthermore, if Figure 5 As shown, the fan 20 is installed outside the housing 10, that is, exposed outside the housing 10. At the same time, the fan 20 can be electrically connected to the mainboard.

[0063] In other embodiments, the fan 20 may also be installed on the inner side of the housing 10 , that is, the fan 20 is covered by the housing 10 or partially covered by the housing 10 .

[0064] Specifically, Figure 6 As shown, the space inside the housing 10 has an air duct. The PFC module, LLC module, and planar transformer 70 are sequentially arranged on the air duct from front to back. The PFC module in the PFC module is directly opposite to the fan 20, and the installation position of the fan 20 is in front of the air duct, that is, in front of the PFC inductor 41. At the same time, in order to increase the output power of the power supply, the bus capacitor 60 generally adopts a large-capacity Bulk capacitor. An output capacitor 80 can also be arranged behind the bus capacitor 60, and the output capacitor 80 is electrically connected to the motherboard.

[0065] In some embodiments, at least one of a synchronous rectification switch of a power supply, a rectification filter capacitor, and a synchronous rectification drive circuit is disposed in the first synchronous rectification region 100 and the second synchronous rectification region 200 .

[0066] Specifically, after the planar transformer 70 is installed in the power supply, multiple synchronous rectification switches and rectification filter capacitors in the synchronous rectification module of the power supply can be integrated on the printed circuit board 71 of the planar transformer 70 at the first synchronous rectification area 100 and the second synchronous rectification area 200, thereby effectively reducing losses.

[0067] It is understandable that when the synchronous rectification switch, the rectification filter capacitor, and the synchronous rectification drive circuit are all arranged in the first synchronous rectification region 100 and the second synchronous rectification region 200, the first power connection region 300 may be provided with a filter capacitor and a drive circuit.

[0068] In another embodiment, Figure 7 As shown, the present application can also arrange the magnetic core area 400 and the first power connection area 300 in sequence along the direction of the air duct, that is, the magnetic core area 400 and the first power connection area 300 are in a front-to-back position relationship.

[0069] In some embodiments, Figure 8 As shown, a first power connection area 300 and a second power connection area 500 are provided on the printed circuit board 71 ; wherein the first power connection area 300 and the second power connection area 500 are both used for the first synchronous rectification area 100 and the second synchronous rectification area.

[0070] Further, the first power connection region 300 , the magnetic core region 400 , and the second power connection region 500 may be sequentially arranged along the first direction.

[0071] Specifically, the first power connection area 300 and the second power connection area 500 can be used to electrically connect the first synchronous rectification area 100 and the second synchronous rectification area 200. The signals required by the synchronous rectification devices in the first synchronous rectification area 100 and the second synchronous rectification area 200 can be transmitted by the first power connection area 300 and the second power connection area 500. At the same time, the DC power output by the synchronous rectification device after synchronous rectification can be output through the first power connection area 300 and the second power connection area 500. Then, the first power connection area 300 and the second power connection area 500 can be provided with synchronous rectification drive circuits and / or rectification filter capacitors. Among them, the synchronous rectification drive circuit can be a driver chip of a synchronous rectification switch tube.

[0072] It should be noted that one or more power connection areas may be provided on the planar transformer 70 , and the positional relationship between the power connection area and the magnetic core area 400 may also be selected according to actual application, and this application does not make any specific limitation.

[0073] In some embodiments, Figure 5 As shown, a plurality of printed circuit boards 71 ​​may be provided in the planar transformer 70, and the magnetic core 72 may be an EI magnetic core; wherein the primary winding and the secondary winding may be provided on a plurality of printed circuit boards 71; and the area between the middle column and the side column of the EI magnetic core corresponds to the area on the printed circuit board 71 where the primary winding and the secondary winding are provided.

[0074] In this embodiment, the power density of the power supply is relatively large, so the planar transformer 70 uses a plurality of printed circuit boards 71, which can achieve loss dispersion, and at the same time, there are gaps between each printed circuit board 71 to facilitate heat dissipation. In addition, the synchronous rectification device and the filter capacitor in the synchronous rectification module can also be set on the corresponding first synchronous rectification area 100 and second synchronous rectification area 200 on each printed circuit board 71.

[0075] The magnetic core 72 may be an EI magnetic core, and the magnetic core area 400 corresponding to the multiple printed circuit boards 71 ​​may be hollowed out according to the structure of the magnetic core 72, so that the magnetic core 72 can be buckled on the printed circuit board 71. It should be noted that the present application may also use other types of magnetic cores, that is, magnetic cores with multiple middle columns and side columns. In other words, the magnetic core 72 may be selected according to the actual application, and the present application does not make any specific limitation.

[0076] In some embodiments, Figure 6 , Figure 7 and Figure 8As shown, a primary pin 73 and a secondary pin 74 are disposed on one side of the printed circuit board 71 , and the primary pin 73 and the secondary pin 74 are both disposed on the same side of the magnetic core 72 .

[0077] In this embodiment, the primary winding and the secondary winding of the planar transformer 70 are both arranged on a printed circuit board 71. The primary pin 73 and the secondary pin 74 can be set on the printed circuit board 71. At the same time, the primary pin 73 and the secondary pin 74 can be arranged on the same side of the printed circuit board 71 to facilitate electrical connection with the main board of the power supply.

[0078] In addition, since the synchronous rectification module of the power supply needs to be electrically connected to the mainboard of the power supply, the secondary pin 74 may include a power pin and a signal pin.

[0079] Furthermore, in some embodiments, the primary pin 73 and the secondary pin 74 are located along the second direction, close to the first synchronous rectification region 100 or close to the second synchronous rectification region 200 .

[0080] In this embodiment, the first synchronous rectification region 100, the magnetic core region 400 and the second synchronous rectification region 200 are arranged in sequence along a direction perpendicular to the second direction. That is to say, the first synchronous rectification region 100, the magnetic core region 400 and the second synchronous rectification region 200 can be arranged in sequence from top to bottom on the printed circuit board 71, and the printed circuit board 71 can be vertically arranged on the main board of the power supply. At this time, one of the first synchronous rectification region 100 and the second synchronous rectification region 200 must be close to the main board, while the other area is far away from the main board. Because the primary winding needs to be electrically connected to the main board of the power supply through the primary pin 73, and the primary pin 73 and the secondary pin 74 are both arranged on the same side of the printed circuit board 71, the primary pin 73 and the secondary pin 74 can be arranged along the second direction, close to the first synchronous rectification region 100 or close to the second synchronous rectification region 200.

[0081] Furthermore, in some embodiments, at least one of the primary pin 73 and the secondary pin 74 is vertically welded to the mainboard of the power supply. Specifically, both the primary pin 73 and the secondary pin 74 can be vertically welded to the mainboard of the power supply, thereby enabling the planar transformer 70 to be vertically arranged on the mainboard of the power supply.

[0082] In some embodiments, a primary circuit of a power supply is electrically connected between the primary pin 73 and the primary winding. In this embodiment, the primary circuit may be a primary inverter circuit, which may be a half-bridge inverter circuit or a full-bridge inverter circuit, and for different topological structures, it may also include circuits such as a resonant capacitor and a resonant inductor, which may be selected according to actual applications, and this application does not make specific limitations.

[0083] The planar transformer 70 provided in the present application includes a printed circuit board 71, a magnetic core 72 buckled at the magnetic core area 400 of the printed circuit board 71, and a winding arranged on the printed circuit board 71. At the same time, a first synchronous rectification area 100, a second synchronous rectification area 200 and a first power connection area 300 are also provided on the printed circuit board 71. The first power connection area 300 and the magnetic core area 400 are arranged along a first direction which is the same as the direction of the air duct in the power supply where the planar transformer is located. The first synchronous rectification area 100, the magnetic core area 400 and the second synchronous rectification area 200 are arranged in sequence along a second direction perpendicular to the first direction. The first synchronous rectification area 100 and the second synchronous rectification area 200 are used for synchronous rectification devices in the power supply where the planar transformer 70 is located. The first power connection area 300 is used for electrically connecting the first synchronous rectification area 100 and the second synchronous rectification area 200. The planar transformer 70 provided in the present application is small in size. After being installed in a high-frequency power supply, the magnetic core 72 of the planar transformer 70 can avoid affecting the heat dissipation of the synchronous rectification device of the power supply, thereby greatly improving the heat dissipation efficiency of the power supply.

[0084] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A planar transformer, characterized in that: include: A printed circuit board, wherein a magnetic core region, a first synchronous rectification region, a second synchronous rectification region and a first power connection region are arranged on the printed circuit board; A magnetic core, disposed in the magnetic core region and buckled with the printed circuit board; The primary winding and the secondary winding are both arranged on the printed circuit board; The primary side pins and the secondary side pins are both arranged on the same side of the printed circuit board; Among them, the first synchronous rectification area and the second synchronous rectification area are used to set up synchronous rectification devices; the first power connection area is used to electrically connect the first synchronous rectification area and the second synchronous rectification area; on the printed circuit board, the first power connection area and the magnetic core area are arranged along a first direction, and the first synchronous rectification area, the magnetic core area and the second synchronous rectification area are arranged along a second direction in sequence, and the first direction is perpendicular to the second direction; the first direction is the same as the direction of the air duct in the power supply where the planar transformer is located.

2. The planar transformer according to claim 1, characterized in that: The first synchronous rectification region and the second synchronous rectification region are provided with synchronous rectification switches and rectification filter capacitors.

3. The planar transformer according to claim 2, characterized in that: Synchronous rectification driving circuits are also provided in the first synchronous rectification region and the second synchronous rectification region.

4. The planar transformer according to claim 1, characterized in that: The printed circuit board is also provided with a second power connection area, and the second power connection area is used to electrically connect the first synchronous rectification area and the second synchronous rectification area.

5. The planar transformer according to claim 4, characterized in that: On the printed circuit board, the first power connection area, the magnetic core area, and the second power connection area are sequentially arranged along the first direction.

6. The planar transformer according to claim 4, characterized in that: The first power connection area is provided with a synchronous rectification drive circuit and / or a rectification filter capacitor; or / and The second power connection area is provided with a synchronous rectification drive circuit and / or a rectification filter capacitor.

7. The planar transformer according to claim 1, characterized in that: The planar transformer comprises a plurality of printed circuit boards, and the magnetic core comprises an EI magnetic core; The area between the middle column and the side column of the EI magnetic core corresponds to the area on the printed circuit board where the primary winding and the secondary winding are arranged.

8. The planar transformer according to claim 1, characterized in that: At least one of the primary pin and the secondary pin is vertically welded to the mainboard of the power supply.

9. The planar transformer according to claim 1, characterized in that: The primary circuit of the power supply is electrically connected between the primary winding and the primary pin.

10. A power supply, characterized in that: include: A planar transformer as claimed in any one of claims 1 to 9; The housing has an air duct; A fan, arranged on the inner side or the outer side of the housing; Wherein, the planar transformer is arranged in the air duct, and the direction of the air duct is the same as the first direction.

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