CN-121641636-B - PCB hollow inductor, design method thereof and switching power supply

CN121641636BCN 121641636 BCN121641636 BCN 121641636BCN-121641636-B

Abstract

The invention provides a PCB hollow inductor, a design method thereof and a switching power supply, wherein the design method comprises the steps of determining the number of turns, the winding width and the winding thickness of windings of the PCB hollow inductor, designing the number of layers of windings in a PCB and the width and the thickness of winding metal in each winding layer, sequentially connecting the winding metal in each winding layer in series to form a PCB winding, wherein the PCB winding is embedded in an insulating support body formed by insulating media, forming a metal shielding body at the periphery of the PCB winding, wherein the metal shielding body is provided with the insulating media between the metal shielding body and the PCB winding, the metal shielding body comprises four peripheral side shielding walls, an upper shielding wall and a lower shielding wall, and the starting end and the tail end of the PCB winding penetrate through the corresponding peripheral side shielding walls through an input terminal and an output terminal respectively and are led out. The invention solves the problems of poor magnetic shielding performance, large high-frequency loss and the like of the PCB planar inductor in the prior art.

Inventors

BA DEJUN
LV XIAOFENG
WANG YIHE
YU FAXIN

Assignees

浙江大学

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (12)

1. The design method of the PCB hollow inductor is characterized by comprising the following steps of: Determining the number of turns, the winding width and the winding thickness of the winding of the PCB hollow inductor, and designing the number of layers of winding layers in the PCB and the width and the thickness of winding metal in each winding layer according to the number of turns, the winding width and the winding thickness; Sequentially connecting winding metals in each winding layer in series to form a PCB winding, wherein the PCB winding is embedded in an insulating support body formed by insulating media; Forming a metal shielding body on the periphery of the PCB winding, wherein the metal shielding body and the PCB winding are provided with the insulating medium; The metal shielding body comprises four peripheral shielding walls, an upper shielding wall and a lower shielding wall, and the starting end and the tail end of the PCB winding penetrate through the corresponding peripheral shielding walls through the input terminal and the output terminal respectively and are led out; the design method further comprises the following steps: Arranging a plurality of first island metals in each winding layer, wherein each first island metal is sequentially arranged between a starting end and a tail end along the outer side edge of the winding metal and is arranged opposite to the corresponding ends of other winding metals; arranging a plurality of second island metals in the upper shielding wall and the lower shielding wall, wherein the second island metals are arranged in one-to-one opposite to the starting end and the tail end of the winding metal in any winding layer and the first island metals; and forming the interlayer interconnection hole by adopting a metallization via hole process so as to electrically interconnect the island metals which are oppositely arranged together.
2. The method for designing a PCB air-core inductor according to claim 1, wherein the method for determining the number of winding turns comprises obtaining an inductance value of the PCB air-core inductor based on an electrical parameter design requirement, obtaining a coil radius and a coil length of the PCB air-core inductor based on a space dimension design requirement, substituting the inductance value, the coil radius and the coil length into an air-core inductor number calculation formula to obtain the number of winding turns, and/or, The method for determining the winding width and the winding thickness comprises the steps of obtaining the maximum current and the maximum current density of the PCB hollow inductor based on the electrical parameter design requirement, obtaining the effective cross-sectional area of the PCB hollow inductor according to the maximum current and the maximum current density, and obtaining the winding width and the winding thickness by combining the space dimension design requirement.
3. The method for designing a PCB hollow core inductor according to claim 1, wherein the method for sequentially connecting the winding metals in each winding layer in series comprises: The initial ends and the tail ends of the winding metals in the adjacent winding layers are arranged in a staggered manner, wherein the tail ends of the winding metals in the upper winding layer are arranged opposite to the initial ends of the winding metals in the lower winding layer; the end of the winding metal in the upper winding layer and the beginning of the winding metal in the lower winding layer are electrically interconnected through the interlayer interconnection holes so as to serially connect the winding metals in each winding layer in sequence.
4. The method of designing a PCB hollow core inductor according to claim 1, wherein the method of forming a metal shield comprises: arranging first shielding metal around the winding metal in each winding layer, wherein the insulating medium is arranged between the first shielding metal and the winding metal; a shielding layer is arranged above a first winding layer and below a last winding layer in the PCB respectively, wherein a second shielding metal is arranged in the shielding layer and at least covers an area surrounded by the first shielding metal; and adopting a metallization via hole process to treat shielding metal of each layer in the PCB, and forming a plurality of metal columns around the PCB winding to serve as four peripheral shielding walls, wherein two shielding layers serve as the upper shielding wall and the lower shielding wall respectively, so that the metal shielding body is formed.
5. The method for designing a PCB air-core inductor according to any one of claims 1-4, further comprising removing the insulating medium in the core region of the PCB winding before forming the metal shield.
6. The method for designing a PCB hollow core inductor according to any one of claims 1 to 4, wherein after forming the metal shield, the method further comprises: a radiator is provided on the upper shielding wall or the lower shielding wall, and/or, And forming an input electrode and an output electrode on the outer side of the upper shielding wall and/or the lower shielding wall, wherein the input electrode and the output electrode are electrically interconnected with the input terminal and the output terminal respectively.
7. A PCB hollow core inductor, the PCB hollow core inductor comprising: the PCB winding is embedded in an insulating support body formed by insulating media and comprises a plurality of winding metals which are sequentially connected in series, wherein each winding metal is formed in each winding layer of the PCB; A metal shield formed at an outer circumference of the PCB winding, wherein the metal shield and the PCB winding have the insulating medium therebetween; The metal shielding body comprises four peripheral shielding walls, an upper shielding wall and a lower shielding wall, and the starting end and the tail end of the PCB winding penetrate through the corresponding peripheral shielding walls through the input terminal and the output terminal respectively and are led out; And a plurality of first island metals are further arranged in each winding layer, wherein each first island metal is sequentially arranged between the starting end and the tail end along the outer side edge of the winding metal and is opposite to the corresponding ends of other winding metals, a plurality of second island metals are further arranged in the upper shielding wall and the lower shielding wall, each second island metal is opposite to each first island metal, and the opposite ends of each island metal and the corresponding winding metal are electrically interconnected through metallized through holes.
8. The PCB hollow core inductor of claim 7, wherein in the PCB winding, the start and end of the winding metal in adjacent winding layers are arranged in a staggered manner, wherein the end of the winding metal in an upper winding layer is disposed opposite to the start of the winding metal in a lower winding layer and is electrically interconnected through an interlayer interconnection hole.
9. The PCB air-core inductor according to claim 7, wherein a first shielding metal is further arranged around the winding metal in each winding layer, the insulating medium is arranged between the first shielding metal and the winding metal, a shielding layer is further arranged above the first winding layer and below the last winding layer in the PCB, a second shielding metal is arranged in the shielding layer and at least covers the area surrounded by the first shielding metal, and the shielding metal of each layer in the PCB forms a plurality of metal columns to serve as four peripheral shielding walls based on metallized through holes, wherein the two shielding layers serve as the upper shielding wall and the lower shielding wall respectively.
10. The PCB hollow core inductor of claim 7, wherein the core region of the PCB winding is hollow.
11. The PCB hollow core inductor according to any one of claims 7-10, wherein the PCB hollow core inductor further comprises: a radiator arranged on the upper shielding wall or the lower shielding wall and/or, And an input electrode and an output electrode formed outside the upper shield wall and/or the lower shield wall, wherein the input electrode and the output electrode are electrically interconnected with the input terminal and the output terminal, respectively.
12. A switching power supply, characterized in that the switching power supply comprises an output inductor, wherein the output inductor is obtained by the design method of the PCB hollow inductor according to any one of claims 1 to 6 or is realized by the PCB hollow inductor according to any one of claims 7 to 11.

Description

PCB hollow inductor, design method thereof and switching power supply Technical Field The invention relates to the technical field of power electronics, in particular to a PCB hollow inductor, a design method thereof and a switching power supply. Background With the wide application of third generation semiconductor devices (such as gallium nitride devices), the operating frequency of the switching power supply is continuously increased to be more than MHz, and the advantages of power density increase, passive element volume reduction and the like are brought by the high frequency, but more severe requirements are also brought to the magnetic element. The traditional winding inductance or magnetic powder core inductance has the problems of large eddy current loss, difficult thermal management, difficult further reduction of volume, easy generation of serious electromagnetic interference (EMI) of a high-frequency magnetic field and the like at high frequency. The planar inductor of the Printed Circuit Board (PCB) is concerned by the advantages of easy integration, high consistency, suitability for automatic production and the like, however, the planar inductor of the PCB is mostly of a simple planar spiral structure, magnetic fields of the planar inductor are distributed in an open mode, strong near-field radiation can be generated under high-frequency high current, peripheral sensitive circuits are interfered, and the planar inductor is also easily interfered by the outside. In addition, conventional magnetic core materials (e.g., ferrite, magnetic powder cores) suffer from a dramatic increase in loss at high frequencies, limiting further increases in efficiency and frequency. Therefore, it is needed to develop a power inductor with high-efficiency magnetic shielding capability, low high-frequency loss, compact structure and easy integration with a PCB so as to meet the application requirements of high-frequency and high-density switching power supplies. It should be noted that the foregoing description of the background art is only for the purpose of providing a clear and complete description of the technical solution of the present invention and is presented for the convenience of understanding by those skilled in the art. The above-described solutions are not considered to be known to the person skilled in the art simply because they are set forth in the background of the invention section. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, the present invention is directed to providing a PCB hollow inductor, a design method thereof, and a switching power supply, which are used for solving the problems of poor magnetic shielding performance, large high frequency loss and the like of the PCB planar inductor in the prior art. To achieve the above and other related objects, the present invention provides a method for designing a PCB hollow inductor, the method comprising: Determining the number of turns, the winding width and the winding thickness of the winding of the PCB hollow inductor, and designing the number of layers of winding layers in the PCB and the width and the thickness of winding metal in each winding layer according to the number of turns, the winding width and the winding thickness; Sequentially connecting winding metals in each winding layer in series to form a PCB winding, wherein the PCB winding is embedded in an insulating support body formed by insulating media; Forming a metal shielding body on the periphery of the PCB winding, wherein the metal shielding body and the PCB winding are provided with the insulating medium; the metal shielding body comprises four peripheral shielding walls, an upper shielding wall and a lower shielding wall, and the starting end and the tail end of the PCB winding penetrate through the corresponding peripheral shielding walls through the input terminal and the output terminal respectively and are led out. Optionally, the method for determining the number of winding turns comprises obtaining an inductance value of the PCB air core inductor based on electrical parameter design requirements, obtaining a coil radius and a coil length of the PCB air core inductor based on space dimension design requirements, substituting the inductance value, the coil radius and the coil length into an air core inductor number calculation formula to obtain the number of winding turns, and/or, The method for determining the winding width and the winding thickness comprises the steps of obtaining the maximum current and the maximum current density of the PCB hollow inductor based on the electrical parameter design requirement, obtaining the effective cross-sectional area of the PCB hollow inductor according to the maximum current and the maximum current density, and obtaining the winding width and the winding thickness by combining the space dimension design requirement. Optionally, the method for sequentially connecting the winding metals in each