Multilayer board planar transformer and power supply

Abstract

The utility model discloses a multilayer board planar transformer and a power supply, which belong to the technical field of transformers and comprise a multilayer printed circuit board, a plurality of pairs of magnetic core groups and windings, the multi-layer printed circuit board comprises a plurality of layers, a plurality of mounting holes which are arranged at intervals are formed in the multi-layer printed circuit board, and the mounting holes correspond to the magnetic core groups one by one; each pair of magnetic core groups comprises a first magnetic core and a second magnetic core, the first magnetic core of each magnetic core group is positioned on the surface of one side of the printed circuit board and extends into the mounting hole, and the second magnetic core of each magnetic core group is positioned on the surface of the other side of the printed circuit board and extends into the mounting hole; the windings are distributed in different levels of the multi-layer printed circuit board; the multi-layer printed circuit board further comprises a plurality of pins, and the pins comprise metal edge covering pins. According to the multilayer board planar transformer and the power supply, the metal edge wrapping pins are used, pin terminals do not need to be additionally installed any more, manufacturing steps are simplified, and the size of a circuit board can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of transformers, and in particular to a multi-layer planar transformer and a power supply. Background Art

[0002] Transformers, essential components of switching power supplies, typically consist of coil windings and a magnetic core. These components are bulky and prone to generating electromagnetic interference. As miniaturization and higher-frequency power supplies become increasingly common, planar transformers are increasingly being used in miniaturized and high-frequency power supplies. Planar transformers offer significantly better electromagnetic interference consistency than traditional wound transformers, and they also offer excellent heat dissipation, a very small height, and high operating frequencies.

[0003] Compared to traditional transformers that use copper wire as windings, planar transformers typically use multi-layer printed circuit boards (PCBs) for their windings. This offers advantages such as high consistency and low processing costs, effectively addressing the size and height issues associated with conventional transformers. However, direct stacking of PCBs can cause electrical interference and short circuits, and planar transformers have many exposed PCB structures, making them susceptible to environmental influences. Therefore, multi-layer planar transformers are currently commonly used to overcome these shortcomings.

[0004] Multilayer planar transformers incorporate all windings onto a single printed circuit board (PCB). This structure allows for tighter coupling between the primary and secondary sides, thereby reducing leakage inductance and the resulting noise. Typically, when mounting a multilayer planar transformer onto a main printed circuit board (PCB), as described in Chinese patent CN 217239237 U, published on August 19, 2022, additional pin terminals are required to electrically connect the planar transformer to the main PCB. This undoubtedly increases the number of manufacturing steps and complexity, while hindering the reduction of the PCB's size. Utility Model Content

[0005] In order to solve the above problems, the utility model provides a multi-layer planar transformer and a power supply.

[0006] In order to achieve the above-mentioned purpose, the technical solution of this utility model is:

[0007] A multilayer planar transformer comprises a multilayer printed circuit board, multiple pairs of magnetic core groups, and windings; the multilayer printed circuit board comprises multiple levels, and is provided with multiple spaced mounting holes, the mounting holes being arranged in a one-to-one correspondence with the magnetic core groups; each pair of the magnetic core groups comprises a first magnetic core and a second magnetic core, the first magnetic core of each magnetic core group being located on one side surface of the printed circuit board and extending into the mounting holes, and the second magnetic core of each magnetic core group being located on the other side surface of the printed circuit board and extending into the mounting holes; the windings are distributed in different levels of the multilayer printed circuit board; the multilayer printed circuit board further comprises multiple pins, the pins comprising metal-clad pins.

[0008] In a specific embodiment, a plurality of first through holes are defined on the pin.

[0009] In a specific embodiment, the winding includes a primary winding, and the primary winding is distributed on different layers at intervals in the multi-layer printed circuit board.

[0010] In a specific embodiment, the winding further includes a secondary winding, and the primary winding and the secondary winding are respectively distributed on different layers with intervals in the multi-layer printed circuit board.

[0011] In a specific embodiment, the shape of the first magnetic core is the same as that of the second magnetic core.

[0012] In a specific embodiment, the first magnetic core and the second magnetic core are connected by an adhesive.

[0013] In a specific embodiment, the multi-layer printed circuit board uses a through-hole process to achieve electrical connection between various layers.

[0014] In a specific embodiment, both the top layer and the bottom layer of the multi-layer printed circuit board are provided with a silk screen layer covering the windings.

[0015] The utility model also provides a power supply, comprising the above-mentioned multilayer planar transformer and a main printed circuit board, wherein at least one slot is provided on the main printed circuit board so that the multilayer planar transformer can be mounted on the main printed circuit board through the slot.

[0016] In a specific embodiment, the shape of the slot matches the shape of the first magnetic core and the second magnetic core.

[0017] Beneficial effects: The utility model provides a multilayer planar transformer and power supply, which, while meeting the characteristics of conventional planar transformers such as high consistency, good heat dissipation, small leakage inductance, small height and high operating frequency, use metal-wrapped pins. As a result, when the multilayer planar transformer is installed on the main printed circuit board, the pins are directly electrically connected to the main printed circuit board, eliminating the need for additional pin terminals, simplifying the manufacturing steps and helping to reduce the size of the circuit board.

[0018] In order to make the above features and advantages of the utility model more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 4 is a circuit diagram of a power supply in a specific embodiment.

[0020] Figure 2 This is a structural schematic diagram of a multi-layer planar transformer and a main printed circuit board of the utility model.

[0021] Figure 3 for Figure 2 Exploded view of a planar transformer in a multilayer board.

[0022] Figure 4 for Figure 2 Schematic diagram of the internal structure of a multi-layer printed circuit board. DETAILED DESCRIPTION

[0023] To make the purpose and technical solutions of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Below is Figure 1 The equivalent circuit diagram of a multilayer planar transformer of the present invention is introduced by taking the power supply in FIG. 1 as an example. Figure 1 The power supply includes transformer T1 and transformer T2, and the input voltage V in The positive electrode is connected to the first end of the capacitor C1 through the inductor L1, and the second end of the capacitor C1 is connected to the input voltage V inThe first end of the capacitor C1 is connected to the negative electrode of the first end of the resistor R1 and the first end of the capacitor C8. The second end of the resistor R1 and the second end of the capacitor C8 are connected to the cathode of the diode D1. The first end of the capacitor C8 is connected to the first end of the primary winding T1A of the transformer T1. The second end of the primary winding T1A of the transformer T1 is connected to the anode of the diode D1. The first end of the first secondary winding T1B of the transformer T1 is connected to the anode of the diode D2. The cathode of the diode D2 is connected to the second end of the first secondary winding T1B of the transformer T1 through the capacitor C2. The two ends of the capacitor C2 output a first output voltage V o1 The first end of the second secondary winding T1C of the transformer T1 is connected to the anode of the diode D3, and the cathode of the diode D3 is connected to the second end of the second secondary winding T1C of the transformer T1 through the capacitor C3. The two ends of the capacitor C3 output the second output voltage V o2 The first end of the third secondary winding T1D of the transformer T1 is connected to the anode of the diode D4, and the cathode of the diode D4 is connected to the second end of the third secondary winding T1D of the transformer T1 through the capacitor C4. The two ends of the capacitor C4 output the first auxiliary voltage V AUX1 .

[0025] Furthermore, the input voltage V in The positive electrode is connected to the first end of the capacitor C5 through the inductor L2, and the second end of the capacitor C5 is connected to the input voltage V in The first end of the capacitor C5 is connected to the negative electrode of the first end of the resistor R2 and the first end of the capacitor C9. The second end of the resistor R2 and the second end of the capacitor C9 are connected to the cathode of the diode D5. The first end of the capacitor C9 is connected to the first end of the primary winding T2A of the transformer T2. The second end of the primary winding T2A of the transformer T2 is connected to the anode of the diode D5. The first end of the first secondary winding T2B of the transformer T2 is connected to the anode of the diode D6. The cathode of the diode D6 is connected to the second end of the first secondary winding T2B of the transformer T2 via the capacitor C6. The two ends of the capacitor C6 output the third output voltage V o3 The first end of the second secondary winding T2C of the transformer T2 is connected to the anode of the diode D6, and the second end of the second secondary winding T2C of the transformer T2 is connected to the second end of the capacitor C6. The first end of the third secondary winding T2D of the transformer T2 is connected to the anode of the diode D7, and the cathode of the diode D7 is connected to the second end of the third secondary winding T2D of the transformer T2 via the capacitor C7. The two ends of the capacitor C7 output the second auxiliary voltage V AUX2 .

[0026] Figure 2This is a schematic diagram of the structure of a multilayer planar transformer and a main printed circuit board in the utility model. Figure 3 for Figure 2 Exploded view of a multilayer planar transformer. Figure 2 and Figure 3 As shown, the utility model is a multilayer planar transformer 1 mounted on a main printed circuit board 2, and the multilayer planar transformer 1 includes Figure 1 Transformer T1 and transformer T2 of the power supply, Figure 1 Other electrical components of the intermediate power supply are arranged on the main printed circuit board 2 .

[0027] Furthermore, the multilayer planar transformer 1 includes a multilayer printed circuit board 11, multiple pairs of magnetic core groups 12 and windings 13; the multilayer printed circuit board 11 includes multiple levels, and a plurality of spaced mounting holes 111 are opened in the multilayer printed circuit board 11, and the mounting holes 111 are arranged one-to-one corresponding to the magnetic core groups 12; each pair of the magnetic core groups 12 includes a first magnetic core 121 and a second magnetic core 122, and the first magnetic core 121 of each magnetic core group is located on one side surface of the printed circuit board 11 and extends into the mounting hole 111, and the second magnetic core 122 of each magnetic core group is located on the other side surface of the printed circuit board 11 and extends into the mounting hole 111; the windings 13 are distributed in different levels of the multilayer printed circuit board 11.

[0028] Optionally, the shape of the first magnetic core 121 is the same as that of the second magnetic core 122 .

[0029] Optionally, the first magnetic core 121 and the second magnetic core 122 are connected by an adhesive, and the adhesive can bond the first magnetic core 121 and the second magnetic core 122 together without affecting the magnetism of the first magnetic core 121 and the second magnetic core 122 .

[0030] Figure 4 for Figure 2 Schematic diagram of the internal structure of the multi-layer printed circuit board 11.

[0031] More specifically, the windings are distributed on different copper foil layers in the multi-layer printed circuit board 11 .

[0032] More specifically, an insulating layer is provided between different copper foil layers.

[0033] Furthermore, the multilayer printed circuit board 11 includes a plurality of pins 113, and the pins 113 include metal-wrapped pins, so that when the multilayer planar transformer 1 is mounted on the main printed circuit board 2, the pins 113 directly form an electrical connection with the main printed circuit board 2, and there is no need to install additional pin terminals.

[0034] Optionally, the primary winding of the transformer T1 is distributed on different layers with intervals in the multilayer printed circuit board 11, and the primary winding of the transformer T2 is distributed on different layers with intervals in the multilayer printed circuit board 11. This can reduce the inter-turn capacitance of the primary winding, which is conducive to reducing electromagnetic interference.

[0035] Optionally, the primary winding and the secondary winding of the transformer T1 are respectively distributed on different layers with intervals in the multilayer printed circuit board 11, and the primary winding and the secondary winding of the transformer T2 are respectively distributed on different layers with intervals in the multilayer printed circuit board 11. This can reduce the coupling coefficient between the primary and secondary sides, thereby making the power supply efficiency higher.

[0036] Furthermore, a plurality of first through holes 1131 are provided on the pins 113 , which not only ensures the firmness of the welding of the multi-layer planar transformer 1 , but also saves labor costs.

[0037] Furthermore, the multilayer printed circuit board 11 adopts a through-hole process to open through-holes in the insulating layer so that the copper foil layers can be electrically connected through the through-holes, which has a simple structure and lower cost.

[0038] Furthermore, the top layer and the bottom layer of the multi-layer printed circuit board 11 are both provided with a silk screen layer covering the windings to achieve an insulation and voltage resistance effect.

[0039] Furthermore, at least one slot 21 is provided on the main printed circuit board 2, so that the multilayer planar transformer 1 can be directly mounted on the main printed circuit board 2 through the slot 21. As a result, the multilayer planar transformer 1 and the main printed circuit board 2 share a thermal pad, achieving integrated heat dissipation. There is no need to provide an additional thermal pad for the multilayer planar transformer 1.

[0040] More specifically, the shape of the slot 21 matches the shapes of the first magnetic core 121 and the second magnetic core 122 , so that the multilayer planar transformer 1 is stuck in the slot 21 .

[0041] The present invention also provides a power supply, including a multilayer planar transformer 1 and a main printed circuit board 2. The main printed circuit board 2 is provided with at least one slot 21, so that the multilayer planar transformer 1 can be directly mounted on the main printed circuit board 2 through the slot 21.

[0042] Although the present invention has been disclosed above with reference to the embodiments, they are not intended to limit the present invention. Anyone with ordinary skill in the art may make slight modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent applications.

Claims

1. A multilayer planar transformer, characterized in that: include: A multilayer printed circuit board, multiple pairs of magnetic core groups, and windings; the multilayer printed circuit board includes multiple levels, and multiple spaced mounting holes are provided in the multilayer printed circuit board, and the mounting holes are arranged in a one-to-one correspondence with the magnetic core groups; each pair of the magnetic core groups includes a first magnetic core and a second magnetic core, the first magnetic core of each magnetic core group is located on one side surface of the printed circuit board and extends into the mounting hole, and the second magnetic core of each magnetic core group is located on the other side surface of the printed circuit board and extends into the mounting hole; the windings are distributed in different levels of the multilayer printed circuit board; the multilayer printed circuit board also includes multiple pins, and the pins include metal-clad pins.

2. A multilayer planar transformer as claimed in claim 1, characterized in that: A plurality of first through holes are formed on the pins.

3. A multilayer planar transformer as claimed in claim 2, characterized in that: The windings include primary windings, and the primary windings are distributed on different layers at intervals in the multi-layer printed circuit board.

4. A multilayer planar transformer as claimed in claim 3, characterized in that: The winding further includes a secondary winding, and the primary winding and the secondary winding are respectively distributed on different layers with intervals in the multi-layer printed circuit board.

5. A multi-layer planar transformer as claimed in claim 1, characterized in that: The shape of the first magnetic core is the same as that of the second magnetic core.

6. A multi-layer planar transformer according to claim 1, characterized in that: The first magnetic core and the second magnetic core are connected by an adhesive.

7. The multi-layer planar transformer according to claim 1, characterized in that: The multi-layer printed circuit board adopts a through-hole process to achieve electrical connection and conduction between various levels.

8. The multi-layer planar transformer according to claim 1, characterized in that: The top layer and the bottom layer of the multilayer printed circuit board are both provided with a silk screen layer covering the windings.

9. A power supply, characterized in that: It comprises a multilayer planar transformer as described in any one of claims 1 to 8, and also comprises a main printed circuit board, wherein at least one slot is opened on the main printed circuit board, so that the multilayer planar transformer is mounted on the main printed circuit board through the slot.

10. A power supply as claimed in claim 9, characterized in that: The shape of the slot matches the shapes of the first magnetic core and the second magnetic core.

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