TWI885320B - Sandwich structure power supply module - Google Patents

Abstract

A sandwich structure power supply module includes stacked inductor pact, PCBs and power device chips. The inductor pack includes a magnetic core and windings. The magnetic core is covered by two pairs of metal layers for connecting to power pins of the power device chips via the PCBs. Compared to the prior art module structure, the disclosed power supply module saves PCB (Printed Circuit Board) footprint, and improves load current/power density. Meanwhile, the disclosed power supply module minimizes the output current trace impedance on PCB and mainly delivers output current through inductor legs to achieve high-efficiency.

Description

Sandwich structure power module

The disclosed embodiments relate to electronic components, and more specifically, the present invention relates to a power module structure.

Generally, a power converter is used to convert input power into output power with appropriate voltage and current for the load. A multiphase power converter includes multiple power stages connected in parallel and working in staggered phases, so it has the advantages of small output voltage ripple, fast transient response, and low rated ripple current requirement for input capacitors. Due to the above advantages, multiphase power converters are widely used in applications with large output current and low voltage, such as servers, microprocessors, etc.

The rapid development of modern GPUs (graphics processing units) and CPUs (central processing units) has put forward higher and higher requirements on the current capability of multi-phase power converters. At the same time, the size of these processors is getting smaller and smaller, which means that the size of multi-phase power converters needs to be reduced accordingly. The increasing current and decreasing size have made the heat dissipation of multi-phase power converters more challenging. In other words, a power converter with high current density, high efficiency and excellent heat dissipation capability is needed.

The purpose of the present invention is to provide a power module with a sandwich structure, which is used to stack and integrate the inductor, power switch and driver in the power circuit system into a smaller module.

According to an embodiment of the present invention, an inductor group for a power module includes: a magnetic core having N channels running through the magnetic core from top to bottom, wherein N is an integer greater than 1; N coils respectively passing through the N channels of the magnetic core; and two groups of metal sheets, each group of metal sheets including two metal sheets, which are bonded after adding an isolation layer in the middle, and the two groups of metal sheets respectively cover two opposite sides of the magnetic core, and the two metal sheets in each group of metal sheets are respectively electrically connected to different potentials.

A power module according to an embodiment of the present invention includes the aforementioned inductor group, and further includes: a PCB top board located on the inductor group; and N power device chips located on the PCB top board, wherein each power device chip has at least one pin electrically connected to a corresponding coil through the PCB top board.

In one embodiment, the power module further includes: a PCB bottom plate, located below the inductor group; and a connector, connecting the PCB top plate and the PCB bottom plate, wherein the connector has a plurality of metal columns, which are respectively welded to corresponding pads of the PCB top plate and the PCB bottom plate.

According to one embodiment of the present invention, an inductor group that can be used in a power module includes: a magnetic core having N channels running through the magnetic core from top to bottom, wherein N is an integer greater than 1; N coils passing through the N channels of the magnetic core respectively; and a first metal sheet, a second metal sheet and a third metal sheet, wherein the first metal sheet and the second metal sheet respectively cover two opposite sides of the magnetic core, and the third metal sheet covers one of the remaining sides of the magnetic core.

The power module with sandwich structure of the present invention has the following advantages: (1) compared with the power module with flat structure in the prior art, it can reduce the area on the PCB board, thereby improving the load current/power density; (2) by transmitting the output current through the legs (coils) of the inductor, it can reduce the routing of the output current loop on the PCB board and avoid the high impedance of the PCB board routing, thereby improving the circuit efficiency; and (3) the structure of the power module of the present invention with the power device chip on the top and the inductor group on the bottom can greatly benefit from the top cooling system commonly used in GPU, CPU and ASIC systems.

In the following description, some specific details, such as the specific circuit structures in the embodiments and the specific parameters of these circuit elements, are used to provide a better understanding of the embodiments of the present invention. Those skilled in the art can understand that the embodiments of the present invention can be implemented even in the absence of some details or in the combination of other methods, elements, materials, etc. In addition, the meaning of "coupled" referred to herein is directly connected or indirectly connected through other circuit elements.

The embodiments described below will use specific implementation devices and application backgrounds as examples to illustrate the devices and working methods of various embodiments of the present invention, so that those skilled in the art can better understand the present invention. However, those skilled in the art should understand that these descriptions are only exemplary and are not intended to limit the scope of the present invention.

FIG1 shows a schematic diagram of the circuit structure of an existing multi-phase power converter 10. As shown in FIG1 , the multi-phase power converter 10 includes a controller 101, N power devices 103 and N inductors L1, where N is an integer and N>1. As shown in FIG1 , each power stage 102, also referred to as each phase 102, includes a power device 103 and an inductor L1. Each power device 103 includes power switches M1, M2 and a driver DR1 for driving the power switches M1, M2. The controller 101 provides N-phase control signals 105-1~105-N to control the N power devices 103 respectively to control the N phases 102 to work out of phase, that is, the N inductors L1 draw energy from the input end in turn and provide energy to the load 104 in turn. It should be understood that in FIG1 , the outputs of each phase of the multi-phase power converter 10 are connected together to provide energy to the load, which is only one application. In other applications, the multi-phase power converter 10 can also work in the manner of multiple single-phase power converters, that is, each phase can be connected to an independent load separately and provide different output voltages to meet the requirements of different loads.

The power stage 102 with the BUCK topology shown in FIG1 is only an example. A person skilled in the art should understand that power stages with other topologies are also applicable to the multi-phase power converter of the embodiment of the present invention.

In the following embodiments of the present invention, the inductor L1 may be implemented by a coupled inductor or by N single inductors.

When N=2, the multi-phase power converter 10 is used as a dual-phase power converter, or two independent power converters.

FIG2 shows a schematic diagram of a power module 20 with a sandwich structure that integrates a dual-phase power converter according to an embodiment of the present invention. In FIG1 , when N=2, the power stage 102 can be implemented by the power module 20. The power module 20 with a sandwich structure includes: a printed circuit board (PCB) bottom plate 201, located at the bottom of the power module 20; an inductor group 206, located on the PCB bottom plate 201, including two inductors, wherein each inductor has a first end and a second end; a PCB top plate 202, located on the inductor group 206; a connector 204, having a plurality of metal pillars 205, each metal pillar 205 being soldered to corresponding pads on the PCB top plate 202 and the PCB bottom plate 201; and Two power device chips 203 are located on the top of the PCB top board 202, wherein each power device chip 203 has one or more pins connected to the second end of the inductor in the inductor group 206 through the PCB top board 202; wherein each inductor has a coil 207, and the two ends of the coil 207 are bent to a plane perpendicular to the length direction of the coil 207 and extend on the PCB top board 202 and the PCB bottom board 201.

In FIG2 , the power module 20 further includes other components 208 that are separately arranged on the PCB top board 202. The components 208 include, for example, various resistors, capacitors, etc. in the power converter 10, such as an input capacitor for providing a pulse current at the input end of the power converter 10, and filter capacitors and resistors for supplying power to the power switch driver and the internal logic circuit.

In one embodiment, the metal pillar 205 includes a copper pillar for soldering the PCB bottom plate 201 to the PCB top plate 202. A person skilled in the art should understand that any metal pillar that can be used to electrically connect two PCB boards can be used in the present invention.

The power module 20 is usually placed on the motherboard of the processor to provide power to the devices on the motherboard. The PCB base plate 201 is welded on the motherboard, and some pins of the power module 20 are welded to the motherboard through the PCB base plate 201. In some embodiments, the PCB base plate 201 can also be omitted. The power module 20 can be directly welded to the motherboard through the connector 204 and the inductor group 206.

In the present invention, the power device chip is stacked on the inductor group, as shown in FIG2, thereby saving the area of the power converter 10 on the PCB board. Each power device chip 203 integrates the power device 103 shown in FIG1, that is, including the power switches M1 and M2 shown in FIG1 and the driver DR1 used to drive the power switches M1 and M2, as well as the circuit connected to the auxiliary coil not shown in FIG1. The pins of the power device chip 203 are soldered to the pads of the PCB top board 202, and then the pads of the PCB top board 202 are electrically connected to the pads of the PCB bottom board 201 through the inductor group 206 and the connector 204. In this way, the power device chip 203 can be electrically connected through the PCB bottom board 201. The power module 20 also includes a metal sheet 209 for conducting large current signals such as reference ground. The metal sheet 209 wraps a portion of the magnetic core of the inductor group 206 and is welded to the PCB top plate 202 and the PCB bottom plate 201 at the same time. The position of the metal sheet 209 depends on the position of the ground pin of the power device chip 203. In the embodiment of Figure 2, the metal sheet 209 is mainly wrapped around the side of the inductor group 206, and its two ends are bent to form welding areas close to the corresponding pads on the PCB board on the upper and lower surfaces of the inductor group 206, so that on the horizontal plane, that is, the plane of the PCB board, a large area of the metal sheet 209 is used to replace the PCB wiring to carry large current, reduce circuit loss, and improve circuit efficiency.

FIG3 shows a three-dimensional exploded view of an inductor assembly 30 according to an embodiment of the present invention. The inductor assembly 30 can be used as the inductor assembly 206 in the power module of FIG2. As shown in FIG3, the inductor assembly 30 includes: a magnetic core, including a first magnetic core portion 301 and a second magnetic core portion 302, wherein the first magnetic core portion 301 and the second magnetic core portion 302 are combined together to form two channels 303-1 and 303-2 at the joint surface of the first magnetic core portion 301 and the second magnetic core portion 302; and coils 304-1 and 304-2, passing through the channels 303-1 and 303-2 respectively.

In the embodiment of FIG. 3 , when the inductor assembly 30 is applied to the power module 20 shown in FIG. 2 , the channels 303 - 1 and 303 - 2 are parallel to the PCB bottom plate 201 and the PCB top plate 202 , that is, the channels 303 - 1 and 303 - 2 have a radial direction along the axis “A” shown in FIG. 2 .

In the embodiment of FIG. 3 , the coil 304-1 has a first end 304-3 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface. The extended part is also equivalent to extending on the surface of the PCB top board 202 and soldered to the PCB top board 202. The coil 304-1 has a second end 304-5 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface. The extended part is also equivalent to extending on the surface of the PCB bottom board 201 and soldered to the PCB bottom board 201. In other words, the first end 304-3 and the second end 304-5 of the coil 304-1 extend along a plane perpendicular to the magnetic core channels 303-1 and 303-2, and the sides of the extended surface also extend on the surfaces of the PCB top board 202 and the PCB bottom board 201. Similarly, the coil 304-2 has a first end 304-4 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface, and the extended part is also equivalent to extending on the surface of the PCB top board 202 and soldered to the PCB top board 202, and has a second end 304-6 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface, and the extended part is also equivalent to extending on the surface of the PCB bottom board 201 and soldered to the PCB bottom board 201. In other words, the first end 304-4 and the second end 304-6 of the coil 304-2 extend along a plane perpendicular to the magnetic core channels 303-1 and 303-2, and the side edges of the extended surface also extend on the surfaces of the PCB top board 202 and the PCB bottom board 201.

In the embodiment of FIG. 3 , the shapes of the first core portion 301 and the second core portion 302 of the magnetic core are not symmetrical, wherein the first core portion 301 has a planar shape, and the second core portion 302 has two grooves, and channels 303-1 and 303-2 are respectively formed by the two grooves of the second core portion 302 and a surface 301-1 of the first core portion 301, as shown in FIG. 3 .

In the embodiment of FIG. 3 , the metal sheets 305-1 and 305-2 have an L shape. The two ends of the metal sheets 305-1 and 305-2 are respectively welded to the PCB top plate 202 and the PCB bottom plate 201. The ends of the metal sheets 305-1 and 305-2 welded to the PCB top plate 202 are bent 90 degrees and extended on the surface of the magnetic core, which is equivalent to extending on the surface of the PCB top plate 202, and are electrically connected to the ground pin of the power device chip 203 through the pad of the PCB top plate 202, thereby reducing the wiring of the PCB top plate 202 and its wiring impedance.

FIG4 shows a three-dimensional exploded view of an inductor assembly 40 according to an embodiment of the present invention. The inductor assembly 40 can be used as the inductor assembly 206 in the power module of FIG2. As shown in FIG4, the inductor assembly 40 includes: a magnetic core, including a first magnetic core portion 401 and a second magnetic core portion 402, wherein the first magnetic core portion 401 and the second magnetic core portion 402 are combined together to form two channels 403-1 and 403-2 at the joint surface of the two; and coils 404-1 and 404-2, passing through the channels 403-1 and 403-2 respectively.

In the embodiment of FIG. 4 , when the inductor assembly 40 is applied to the power module 20 shown in FIG. 2 , the channels 403-1 and 403-2 are perpendicular to the PCB bottom plate 201 and the PCB top plate 202 , that is, the channels 403-1 and 403-2 have a radial direction along the axis “B” shown in FIG. 2 .

In the embodiment of FIG. 4 , the coil 404-1 has a first end 404-3 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface, and the extended part is also equivalent to extending on the surface of the PCB top board 202, and is soldered to the PCB top board 202, and has a second end 404-5 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface, and the extended part is also equivalent to extending on the surface of the PCB bottom board 201, and is soldered to the PCB bottom board 201. In other words, the first end 404-3 and the second end 404-5 of the coil 404-1 extend along a plane perpendicular to the magnetic core channels 403-1 and 403-2, and the extended surface also extends on the surface of the PCB top board 202 and the PCB bottom board 201. Similarly, the coil 404-2 has a first end 404-4 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface, and the extended part is also equivalent to extending on the surface of the PCB top board 202 and soldered to the PCB top board 202, and has a second end 404-6 bent 90 degrees and extending on the surface of the magnetic core, and covering a part of the surface, and the extended part is also equivalent to extending on the surface of the PCB bottom board 201 and soldered to the PCB bottom board 201. In other words, the first end 404-4 and the second end 404-6 of the coil 404-2 extend along a plane perpendicular to the magnetic core channels 403-1 and 403-2, and the extension surface also extends on the surface of the PCB top board 202 and the PCB bottom board 201.

In some embodiments, the second end 404-5 of the coil 404-1 and the second end 404-6 of the coil 404-2 may not be bent. Whether the second end of the coil is bent, the direction of the bend and the shape of the extended surface, etc., depends on the position of the corresponding pad on the PCB bottom plate 201, or if there is no PCB bottom plate 202, it depends on the position of the corresponding pad on the motherboard where the power module 20 is located.

In the embodiment of FIG. 4 , the shapes of the first core portion 401 and the second core portion 402 of the magnetic core are not symmetrical, wherein the first core portion 401 has a planar shape, the second core portion 402 has two grooves, and channels 403-1 and 403-2 are respectively formed by the two grooves of the second core portion 402 and a surface 401-1 of the first core portion 401.

In the embodiment of FIG. 4 , the metal sheets 405-1 and 405-2 have a C-shape. The two ends of the metal sheets 405-1 and 405-2 are respectively welded to the PCB top plate 202 and the PCB bottom plate 201. One end of the metal sheets 405-1 and 405-2 welded to the PCB bottom plate 201 is bent 90 degrees and extended on the surface of the magnetic core, which is equivalent to extending on the surface of the PCB bottom plate 201. The extended surface is welded to the corresponding pad of the PCB bottom plate 201, thereby reducing the routing of the PCB bottom plate 201 and its routing impedance. Similarly, the metal sheets 405-1 and 405-2 are welded to one end of the PCB top plate 202 and bent 90 degrees to extend on the surface of the magnetic core, which is equivalent to extending on the surface of the PCB top plate 202, and are electrically connected to the ground pin of the power device chip 203 through the solder pad of the PCB top plate 202, thereby reducing the routing of the PCB top plate 202 and its routing impedance.

FIG5 shows a three-dimensional exploded view of an inductor assembly 50 according to an embodiment of the present invention. The inductor assembly 50 can be used as the inductor assembly 206 in the power module of FIG2. As shown in FIG5, the inductor assembly 50 includes: a magnetic core, including a first magnetic core portion 501 and a second magnetic core portion 502, wherein the first magnetic core portion 501 and the second magnetic core portion 502 are combined together to form two channels 503-1 and 503-2 at the joint surface of the first magnetic core portion 501 and the second magnetic core portion 502; and coils 504-1 and 504-2, passing through the channels 503-1 and 503-2 respectively.

In the embodiment of FIG. 5 , when the inductor assembly 50 is applied to the power module 20 shown in FIG. 2 , the channels 503 - 1 and 503 - 2 are perpendicular to the PCB bottom plate 201 and the PCB top plate 202 , that is, the channels 503 - 1 and 503 - 2 have a radial direction along the axis “B” shown in FIG. 2 .

In the embodiment of FIG. 5 , the metal sheet 505 has a C-shape. The two ends of the metal sheet 505 are respectively welded to the PCB top plate 202 and the PCB bottom plate 201. One end of the metal sheet 505 welded to the PCB bottom plate 201 is bent 90 degrees and extended on the surface of the magnetic core, which is equivalent to extending on the surface of the PCB bottom plate 201. The extended surface is welded to the corresponding pad of the PCB bottom plate 201, thereby reducing the routing of the PCB bottom plate 201 and its routing impedance. Similarly, one end of the metal sheet 505 soldered to the PCB top board 202 is bent 90 degrees and extended on the surface of the magnetic core, which is equivalent to extending on the surface of the PCB top board 202, and is electrically connected to the ground pin of the power device chip 203 through the solder pad of the PCB top board 202, thereby reducing the wiring of the PCB top board 202 and its wiring impedance. In the embodiment of FIG. 5, the part of the metal sheet 505 that wraps the side surface of the magnetic core is extended as much as possible to increase the area to reduce its own impedance.

Compared with the inductor assembly 40 shown in FIG4 , the inductor assembly 50 in FIG5 has a single metal sheet 505 for electrically connecting the ground pin of the power device chip 203 to the PCB bottom plate 201. Compared with FIG4 , FIG5 lacks a metal sheet, so the metal sheet 505 and the coils 504-1 and 504-2 have a larger extensible area on the upper and lower surfaces of the magnetic core, thereby making the distribution of the ground pin of the power device chip 203 more flexible.

In FIG. 5 , the first magnetic core portion 501 and the second magnetic core portion 502 of the magnetic core are similar to the magnetic core structure in FIG. 4 , and for the sake of brevity, they are not further described here.

FIG6 shows a schematic diagram of the structure of a magnetic core 60 according to an embodiment of the present invention. In FIG6, the magnetic core 60 includes a first magnetic core portion 601 and a second magnetic core portion 602 of symmetrical shapes, wherein each magnetic core portion has two grooves. When the magnetic core 60 is used in the inductor assembly of the embodiments of FIG3-FIG5, the grooves of the two magnetic core portions overlap to form two channels for the coil to pass through.

FIG. 7 shows a schematic diagram of the structure of a magnetic core 70 according to an embodiment of the present invention. In FIG. 7 , the magnetic core 70 includes a first magnetic core portion 701, a second magnetic core portion 702, and a third magnetic core portion 703-1 to 703-3. The first magnetic core portion 701, the second magnetic core portion 702, and the third magnetic core portions 703-1 and 703-2 construct a first channel 704-1. The first magnetic core portion 701, the second magnetic core portion 702, and the third magnetic core portions 703-2 and 703-3 construct a second channel 704-2. As can be seen from FIG. 7 , when there are more third magnetic core portions, more magnetic core channels can be constructed. The first magnetic core portion 701, the second magnetic core portion 702, and the third magnetic core portions 703-1 to 703-3 can be made of different materials, thereby providing a more flexible and adjustable inductance-current curve.

In some embodiments of the present invention, the core parts of the magnetic core can be made of the same material but have different shapes, or made of different materials, such as ferrite, iron powder or other suitable materials, in order to achieve the desired inductance-current characteristic curve, for example, a large inductance value at a small current and a small inductance value at a large current. A large inductance value at a small current can make the system more efficient, while a small inductance value at a large current can make the system transient better.

For the purpose of briefly explaining the principle of the present invention, the embodiments of FIG. 3 to FIG. 5 only show a magnetic core having two channels through which two coils can be passed. A person skilled in the art should know that, according to the needs of the application, the magnetic core can have any number of channels through which any number of coils can be passed, and single or multiple channels are in line with the subject matter of the present invention.

In some embodiments, there may be air gaps between different core parts of the magnetic core to form coupled inductors. In some embodiments, there are no air gaps between the core parts, thereby forming multiple single inductors.

In the present invention, in order to make the surface of the inductor module flat, the coil and metal sheet covering the surface of the magnetic core are embedded in the surface of the magnetic core, as shown in Figures 3 to 5.

FIG8 shows a three-dimensional exploded view of an inductor 80 according to an embodiment of the present invention. The inductor 80 can be used as the inductor 206 in the power module of FIG2. As shown in FIG8, the inductor 80 includes: a magnetic core having a symmetrical structure in a top view, two channels 801-1 and 801-2 passing through the upper surface 801-3 of the magnetic core 801 to the lower surface 801-4, and symmetrically distributed on both sides of the center axis "D" in the top view; and coils 802-1 and 802-2 passing through the channels 801-1 and 801-2 respectively.

In the embodiment of FIG. 8 , when the inductor 80 is applied to the power module 20 shown in FIG. 2 , the channels 801-1 and 801-2 are perpendicular to the PCB bottom plate 201 and the PCB top plate 202 , that is, the channels 801-1 and 801-2 have a radial direction along the axis “B” shown in FIG. 2 .

In the embodiment of FIG. 8 , coils 802 - 1 and 802 - 2 are straight strip structures.

In the embodiment of FIG8 , the metal sheets 803-1, 803-2, 805-1 and 805-2 are “C” shaped when viewed from the side, closely attached to the magnetic core 801 and partially wrapped around the magnetic core 801. The metal sheets 805-1, 805-2 and 806 are used to weld the PCB top plate 202 and the PCB bottom plate 201. As shown in FIG8 , both ends of the metal sheets 803-1, 803-2, 805-1 and 805-2 are bent 90 degrees and extended along the PCB top plate 202 and the PCB bottom plate 201. The extended surface is welded to the corresponding pads of the PCB top plate 202 and the PCB bottom plate 201, thereby saving the internal wiring of the PCB board and minimizing the high impedance caused by the internal wiring of the PCB board. In one embodiment, metal sheets 803-1 and 803-2 are used to electrically connect the power pins of the power device chip 203 (the pins for receiving the input voltage Vin shown in FIG. 1) to the PCB bottom plate 201 or the motherboard through the PCB top plate 202. Metal sheets 805-1 and 805-2 are used to electrically connect the ground pins of the power device chip 203 to the PCB bottom plate 201 or the motherboard through the PCB top plate 202. In the embodiment of FIG. 8, the middle parts of the two ends of the metal sheets 803-1 and 803-2 are hollowed out, leaving the two side parts for connecting the PCB board. Matchingly, the two side parts of the two ends of the metal sheets 805-1 and 805-2 are hollowed out, leaving the middle parts for connecting the PCB board. An isolation layer 804-1 is added between the metal sheet 803-1 and the metal sheet 805-1, and after bonding, the isolation layer 804-1 is covered on one side of the magnetic core 801. Similarly, an isolation layer 804-2 is added between the metal sheet 803-2 and the metal sheet 805-2, and after bonding, the isolation layer 804-2 is covered on the other opposite side of the magnetic core 801. The isolation layer 804-1 is used to prevent the metal sheet 803-1 and the metal sheet 805-1 from short-circuiting. The isolation layer 804-2 is used to prevent the metal sheet 803-2 and the metal sheet 805-2 from short-circuiting. The upper and lower ends of the metal sheets 803-1, 803-2, 805-1 and 805-2 are bent and cover the upper and lower surfaces of the magnetic core 801 as much as possible to minimize the internal wiring of the PCB board and reduce the wiring impedance of the PCB board. At the same time, the metal sheets 803-1, 803-2, 805-1 and 805-2 are as wide as possible to reduce the resistance of the metal sheets themselves.

It should be understood that in some embodiments, metal sheets 803-1 and 803-2 can be electrically connected to the ground pin of the power device chip 203 through the PCB top plate 202, and metal sheets 805-1 and 805-2 can be electrically connected to the power pin of the power device chip 203 through the PCB top plate 202, that is, the potential of the connection between metal sheets 803-1 and 803-2 and the potential of the connection between metal sheets 805-1 and 805-2 can be interchanged.

FIG. 9 shows a three-dimensional exploded view of an inductor 90 according to an embodiment of the present invention. The inductor 90 can be used as the inductor 206 in the power module of FIG. 2. The inductor group 90 is similar to the inductor group 80 in FIG. 8, except that in FIG. 9, the coils 902-1 and 902-2 are not straight strip structures like the coils 801-1 and 801-2 in FIG. 8. In FIG. 9, the coils 902-1 and 902-2 respectively include three parts, wherein the first part 902-A extends downward from the upper surface 901-3 and is perpendicular to the upper surface 901-3, the second part 902-B extends upward from the lower surface 901-4 and is perpendicular to the lower surface 901-4, and the third part 902-C connects the first part 902-A and 902-B in the middle. In one embodiment, the third portion 902-C is radially parallel to the upper surface 901-3 and the lower surface 901-4 of the magnetic core.

FIG10 shows a three-dimensional exploded view of an inductor 100 according to an embodiment of the present invention. The inductor 100 can be used as the inductor 206 in the power module of FIG2. The inductor assembly 100 is similar to the inductor assembly 90 in FIG9, except that, in FIG10, the third portion 1002-C of each coil is long enough so that the first portion 1002-A and the second portion 1002-B of the coil are exposed on the surface of the magnetic core, wherein the exposed surfaces of the first portion 1002-A and the second portion 1002-B are flush with the surface of the magnetic core to make the surface of the magnetic core flat.

FIG. 11 shows a three-dimensional exploded view of an inductor assembly 110 according to an embodiment of the present invention. The inductor assembly 110 can be used as the inductor 206 in the power module of FIG. 2 . The inductor assembly 110 is similar to the inductor assembly 100 in FIG. 10 , except that, in FIG. 11 , the third portion 1102-C of each coil is long enough so that the first portion 1102-A and the second portion 1102-B of the coil are exposed on the surface of the magnetic core, wherein the exposed surfaces of the first portion 1102-A and the second portion 1102-B are flush with the surface of the magnetic core to make the surface of the magnetic core flat. In one embodiment, the third portion 1102-C is radially parallel to the upper surface 1101-3 and the lower surface 1101-4 of the magnetic core.

FIG. 12 shows a three-dimensional exploded view of an inductor assembly 120 according to an embodiment of the present invention. The inductor assembly 120 can be used as the inductor 206 in the power module of FIG. 2 . The inductor assembly 120 is similar to the inductor assembly 100 in FIG. 10 , except that in FIG. 12 , the metal sheets 1203-1, 1203-2, and 1204 do not cover each other. In FIG. 12 , the metal sheets 1203-1 and 1203-2 cover two opposite sides of the magnetic core 1001, and the metal sheet 1204 covers any remaining side. Seen from the side, the metal sheets 1203-1, 1203-2 and 1204 are all "C" shaped, that is, after the two ends of each metal sheet are bent 90 degrees, they wrap around the upper surface 1001-3 and part of the lower surface 1001-4 of the magnetic core 1001.

In the embodiment of FIG12 , metal sheets 1203-1 and 1203-2 are connected to a first potential, and metal sheet 1204 is connected to a second potential. The first potential may be the potential of a ground pin of the power device 203, and the second potential may be the potential of a power pin of the power device 203, and vice versa.

FIG13 shows a three-dimensional exploded view of an inductor group 130 according to an embodiment of the present invention. The inductor group 130 can be used as the inductor 206 in the power module of FIG2 . The inductor group 130 is similar to the inductor group 120 in FIG12 , except that in FIG13 , the inductor group 130 includes more metal sheets, that is, the inductor group 130 includes metal sheets 1203-1, 1203-2, 1304-1 and 1304-2. In FIG13 , the metal sheets 1203-1 and 1203-2 cover two opposite sides of the magnetic core 1001 and are electrically connected to the first potential, while the metal sheets 1304-1 and 1304-2 cover the remaining two opposite sides, respectively, and are electrically connected to the second potential. Similar to the metal sheet in FIG. 12 , metal sheets 1203-1, 1203-2, 1304-1 and 1304-2 are all “C” shaped when viewed from the side, i.e., each metal sheet is bent 90 degrees at both ends to wrap around a portion of the upper surface 1001-3 and the lower surface 1001-4 of the magnetic core 1001. More metal layer distribution provides greater flexibility for the distribution of pads on the top PCB 202 and the bottom PCB 201 (or the motherboard where the power module is located).

In different embodiments of the present invention, the metal sheet can have different shapes to wrap the magnetic core. Moreover, when the shape of the magnetic core changes, the shape of the metal sheet will also change accordingly. It should be understood that the metal sheet and the coil do not touch each other to avoid short circuit.

In some embodiments, the metal sheets in FIGS. 8-13 may have different shapes, such as an "L" shape, that is, one end of the metal sheet is bent and includes the upper surface or the lower surface of the magnetic core, as shown in the metal sheets 305-1 and 305-2 in FIG. 3. In some embodiments, some metal sheets or metal sheets as shown in FIGS. 8-13 may be flat, that is, none of the ends are bent. Furthermore, in some embodiments, metal sheets of different shapes, such as a "C" shape and a flat shape, may be combined together as long as there is an isolation layer in the middle.

In the present invention, the coil passes through a channel inside the magnetic core, which means that the channel and the coil have matching shapes. In some embodiments, the coil is first shaped and then the coil is wrapped with the magnetic core material to make the entire inductor.

In some embodiments of the present invention, the surface of the magnetic core has an epoxy coating to isolate the magnetic core from the metal layer covering it.

In the present invention, in order to make the outer surface of the inductor flat, the portion of the coil exposed on the outer surface of the inductor and the metal layer covering the outer surface of the inductor are embedded into the outer surface of the inductor, as shown in FIGS. 3-5 and 8-13.

In summary, many changes and variations of the present invention are obviously feasible. Therefore, it should be understood that within the scope defined by the patent application, the present invention may not be implemented according to the above specific description. It should also be understood that the above disclosure only relates to some preferred embodiments of the present invention, and changes may be made to the present invention without departing from the spirit and scope defined by the patent application of the present invention. When only one preferred embodiment is disclosed, it is not difficult for ordinary technicians in this field to think of its variations and put them into practice without departing from the spirit and scope defined by the patent application of the present invention.

10: Multiphase power converter 101: Controller 102: Power stage 103: Power device 104: Load M1, M2: Power switch DR1: Driver L1, 80, 90, 100: Inductor 20: Power module 201: PCB bottom plate 202: PCB top plate 203: Power device chip 204: Connector 205: Metal pillar 206: Inductor group. 207, 304-1, 304-2, 404-1, 404-2, 504-1, 504-2, 802-1, 802-2, 902-1, 902-2, 1002-1, 1002-2, 1102-1, 1102-2: Coil 208: Components 209,305-1,305-2,405-1,405-2,505,803-1,803-2,805-1,805-2, 1203-1,1203-2,1204,1304-1,1304-2: Metal sheets 30,40,50,110: Inductor 301,302,401,402,501,502,601,602,701,702,703-1,703-2, 703-3: Magnetic core 303-1,303-2,403-1,403-2,503-1,503-2,704-1,704-2,801-1, 801-2,901-1,901-2,1001-1,1001-2,1101-1,1101-2: Channel 304-3,304-4,304-5,304-6,404-3,404-4,404-5,404-6,504-3, 504-4,504-5,504-6: Endpoint 301-1,401-1,501-1: Surface 60,70,801,901,1001,1101: Core 801-3,801-4,901-3,901-4,1001-3,1001-4,1101-3,1101-4: Surface 804-1,804-2: Isolation layer 902-A,902-B,902-C,1102-A,1102-B,1102-C: Coil part 105-1~105-N: Control signal

In order to better understand the present invention, the present disclosure will be described in detail according to the following drawings. The same components have the same drawing numbers. The following drawings are for illustration only and may only show part of the device and may not be drawn to actual scale. [Figure 1] shows a circuit diagram of an existing multi-phase power converter 10; [Figure 2] shows a schematic diagram of a power module 20 with a sandwich structure that integrates a two-phase power converter according to an embodiment of the present invention; [Figure 3] shows a three-dimensional exploded view of an inductor group 30 according to an embodiment of the present invention; [Figure 4] shows a three-dimensional exploded view of an inductor group 40 according to an embodiment of the present invention; [Figure 5] shows a three-dimensional exploded view of an inductor group 50 according to an embodiment of the present invention; [Figure 6] shows a structural schematic diagram of a magnetic core 60 according to an embodiment of the present invention; [Figure 7] shows a structural schematic diagram of a magnetic core 70 according to an embodiment of the present invention; [Figure 8] shows a three-dimensional exploded view of an inductor group 80 according to an embodiment of the present invention; [Figure 9] shows a three-dimensional exploded view of an inductor group 90 according to an embodiment of the present invention; [Figure 10] shows a three-dimensional exploded view of an inductor group 100 according to an embodiment of the present invention. [Figure 11] shows a three-dimensional exploded view of an inductor group 110 according to an embodiment of the present invention. [Figure 12] shows a three-dimensional exploded view of an inductor group 120 according to an embodiment of the present invention. [Figure 13] shows a three-dimensional exploded view of an inductor group 130 according to an embodiment of the present invention.

80: Inductor

801: Magnetic core

801-1,801-2: Channel

801-3,801-4: Surface

802-1,802-2: Coil

803-1,803-2,805-1,805-2:Metal sheet

804-1,804-2: Isolation Layer

Claims (17)

An inductor group for a power module includes: a magnetic core having N channels running through the magnetic core from top to bottom, wherein N is an integer greater than 1; N coils respectively passing through the N channels of the magnetic core; and two groups of metal sheets, each group of metal sheets including two metal sheets, which are bonded after adding an isolation layer in the middle, and the two groups of metal sheets respectively cover two opposite sides of the magnetic core, and the two metal sheets in each group of metal sheets are respectively electrically connected to different potentials. The inductor assembly as described in claim 1, wherein at least one of the metal sheets is in a "C" shape, having a first end bent and extending on an upper surface of the magnetic core, and having a second end bent and extending on a lower surface of the magnetic core. The inductor assembly as described in claim 1, wherein at least one of the metal sheets is in an inverted "L" shape, with one end bent and extending on an upper surface of the magnetic core. The inductor assembly as described in claim 1, wherein at least one of the metal sheets is in an "L" shape, with one end bent and extending on the lower surface of the magnetic core. An inductor assembly as described in claim 1, wherein the metal sheet has a planar shape. An inductor assembly as described in claim 1, wherein the coil is straight. The inductor set as described in claim 1, wherein each of the coils includes a first portion, a second portion and a third portion, the first portion extending downward from an upper surface of the magnetic core and perpendicular to the upper surface of the magnetic core, the second portion extending upward from a lower surface of the magnetic core and perpendicular to the lower surface of the magnetic core, and the third portion connecting the first portion and the second portion inside the magnetic core. An inductor assembly as described in claim 7, wherein the length of the third portion is parallel to the upper surface of the magnetic core and is long enough to allow the first portion and the second portion to be exposed on one side of the magnetic core. The inductor assembly as described in claim 1, wherein each coil includes a first part, a second part and a third part, the first part extends from one side of the magnetic core to the inside of the magnetic core and is exposed on an upper surface of the magnetic core, the second part extends from another opposite side of the magnetic core to the inside of the magnetic core and is exposed on a lower surface of the magnetic core, and the third part connects the first part and the second part inside the magnetic core. A power module, comprising an inductor group as described in any one of claim items 1-9, and further comprising: a PCB top board located on the inductor group; and N power device chips located on the PCB top board, wherein each power device chip has at least one pin electrically connected to the corresponding coil through the PCB top board. The power module as described in claim 10 further comprises: a PCB bottom plate, located under the inductor group; and a connector, connecting the PCB top plate and the PCB bottom plate, wherein the connector has a plurality of metal pillars, which are respectively soldered to a corresponding pad of the PCB top plate and the PCB bottom plate. An inductor group that can be used in a power module includes: a magnetic core having N channels running through the magnetic core from top to bottom, wherein N is an integer greater than 1; N coils, respectively passing through the N channels of the magnetic core; and a first metal sheet, a second metal sheet and a third metal sheet, wherein the first metal sheet and the second metal sheet respectively cover two opposite sides of the magnetic core, and the third metal sheet covers one of the remaining sides of the magnetic core, wherein the first metal sheet, the second metal sheet and the third metal sheet can be used to connect one or more potentials. An inductor assembly as described in claim 12, wherein the first metal sheet and the second metal sheet are electrically connected to a first potential, and the third metal sheet is electrically connected to a second potential. The inductor assembly as described in claim 12 further includes a fourth metal sheet covering the side of the magnetic core opposite to the side where the third metal sheet is located. The inductor set as described in claim 14, wherein the first metal sheet and the second metal sheet are electrically connected to a first potential, and the third metal sheet and the fourth metal sheet are electrically connected to a second potential. An inductor assembly as described in claim 12, wherein each coil includes a first portion, a second portion, and a third portion, wherein the first portion extends downward from an upper surface of the magnetic core and is perpendicular to the upper surface of the magnetic core, the second portion extends upward from a lower surface of the magnetic core and is perpendicular to the lower surface of the magnetic core, and the third portion connects the first portion and the second portion inside the magnetic core. An inductor assembly as described in claim 16, wherein the length of the third portion is parallel to the upper surface of the magnetic core and is long enough to allow the first portion and the second portion to be exposed on the side of the magnetic core.

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