Inductance device and power converter using same

Abstract

An inductance device comprises a supporting body, a magnetic core and a plurality of branches. The magnetic core is arranged in the supporting body. And a plurality of branches arranged on the support body and connected in parallel with each other. Each of the plurality of branches has a winding structure and respectively surrounds the magnetic core. And all the windings arranged on different branches are arranged in a mutually staggered manner.

Description

TECHNICAL FIELD

[0001] The present application relates to electronic components, and more particularly to inductors used in power conversion devices. BACKGROUND

[0002] An inductor is a component that operates on the principle of electromagnetic induction. Inductors store energy in a magnetic field and play a key role in many electronic and power systems. In the context of power supply and filtering applications, inductors are responsible for energy storage and voltage conversion in power converters, such as DC-DC converters (e.g., Buck, Boost converters), and filter out high-frequency interference in the voltage to protect the circuit from operating stably.

[0003] Generally, the basic structure of an inductor includes a winding and a magnetic core. The winding is mainly in the form of a coil, which generates a magnetic field when an electric current passes through it. The magnetic core serves as the main magnetic path and restricts the magnetic flux path within the core to concentrate and strengthen the magnetic field, thereby achieving the effect of increasing inductance. The types of magnetic cores include toroids, E-shapes, U-shapes, bar shapes, column shapes, etc., which may differ depending on the application.

[0004] With the increasing demand for miniaturization of power converters, the use of space in electronic products is becoming increasingly tight. Although traditional inductors can achieve a higher inductance in a limited volume / size, space is still needed on the surface of the printed circuit board (PCB) on which the inductor is disposed to set and fix the magnetic core, thereby occupying a portion of the product design volume (space). SUMMARY

[0005] In view of the above, the present application proposes an inductor that integrates the magnetic core into the support body to avoid occupying the surface of the printed circuit board and improves inductance and reduces conductor loss by using a specific branch, winding configuration, and board layer arrangement.

[0006] One embodiment of the present application proposes an inductor, comprising: a support body, a magnetic core, and a plurality of branches. The magnetic core is disposed in the support body. The plurality of branches are disposed in the support body and connected in parallel with each other. Each of the plurality of branches has a winding structure and surrounds the magnetic core.

[0007] According to some aspects of the foregoing embodiment, the support body includes a plurality of board layers, and each of the plurality of board layers is provided with a winding. The winding structure of each of the plurality of branches is composed of a predetermined number of windings connected in series. Moreover, the predetermined number of windings are disposed on different board layers.

[0008] According to some aspects of the foregoing embodiments, the plurality of branches comprises a first branch and an nth branch, and all windings disposed on different branches are disposed in an interleaved manner.

[0009] According to some aspects of the foregoing embodiments, n is at least 2, and the predetermined number is at least 2.

[0010] According to some aspects of the foregoing embodiments, the plurality of branches comprises a first branch and an nth branch, and the plurality of windings of the plurality of winding structures constituting the first branch and the nth branch are disposed in a symmetrical manner.

[0011] According to some aspects of the foregoing embodiments, each of the first branch and the nth branch comprises at least one winding and another winding, and the symmetrical disposition comprises: from the one winding of the first branch to the one winding of the nth branch, and from the one winding of the nth winding to the other winding of the first branch.

[0012] According to some aspects of the foregoing embodiments, the product of the predetermined number and the number of branches is not greater than the number of the plurality of board layers.

[0013] According to some aspects of the foregoing embodiments, the surface layer of the support body covers the magnetic core.

[0014] According to some aspects of the foregoing embodiments, the support body is a multi-layer printed circuit board.

[0015] According to some aspects of the foregoing embodiments, the winding disposed on each board layer is composed of a conductor.

[0016] According to some aspects of the foregoing embodiments, the conductor is copper.

[0017] According to some aspects of the foregoing embodiments, the portion of the magnetic core surrounded by the winding is a continuous structure.

[0018] According to some aspects of the foregoing embodiments, the magnetic core is inlaid in the support body.

[0019] Another embodiment of the present application provides a power converter, comprising: a switching module, and the inductor device as described above, and the inductor device is coupled to the switching module. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A schematic diagram showing the winding structure of two inductors.

[0021] Figure 2 A schematic diagram showing the structure of the inductor device of the present application.

[0022] Figure 3 A schematic diagram showing Figure 2 A diagram showing the configuration relationship between the branches and the board layers of the inductor device.

[0023] Wherein, the reference numerals are explained as follows:

[0024] 11, 12: winding structure

[0025] w a ~ w f : coil

[0026] 20: inductance device

[0027] 21: support body (printed circuit substrate)

[0028] 22: magnetic core

[0029] LL1~LL6: plate layer

[0030] B1~B6: 1st branch~3rd branch

[0031] w1~w6: winding on LL1~LL6 plate layer

[0032] I: current flowing through inductance device

[0033] I1~I3: current flowing through 1st branch~3rd branch DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objectives, features and advantages of the present application more apparent and easy to understand, the following preferred embodiments are specifically described in detail below, together with the accompanying drawings.

[0035] Figure 1 Schematic diagram showing winding structure of two inductors. Figure 1 Among them, winding 11 is a 3-layer structure, having coils w a , w b and w c respectively arranged on the 1st layer, the 2nd layer and the 3rd layer. Winding 12 is also a 3-layer structure, having coils w d , w e and w f respectively arranged on the 1st layer, the 2nd layer and the 3rd layer. It should be noted that the number of turns of coils w a ~ w b are all 1, and coils w a ~ w c are connected in series; the number of turns of coils w d ~ w f are all 3, and coils w d ~ w f are connected in parallel. The equivalent number of turns of winding 11 and winding 12 are both 3.

[0036] In the same footprint, for example, 160mm 2In the case of the inductance and copper loss of the winding 11 and the winding 12, the results are shown in Table 1.

[0037] Table 1

[0038]

[0039] From Table 1, it can be seen that the winding 11 (1 turn per 1 layer, 3 layers in series) can achieve a higher inductance per unit of copper loss (conductor loss) than the winding 12 (3 turns per 1 layer, 3 layers in parallel).

[0040] Referring to Equation [1], when two inductors (or windings) L1 and L2 (the inductance is assumed to be L) are connected in parallel and are perfectly coupled to each other (i.e., the mutual inductance M of L1 and L2 is L), the parallel equivalent inductance L of the inductors L1 and L2 eq will ideally remain L.

[0041]

[0042] However, in reality, inductors (windings) disposed in different layers are not perfectly coupled to each other, and the inductance decreases as the number of layers connected in parallel increases, and the difficulty of achieving the target inductance increases.

[0043] The inductance device (inductor) of the present application introduces a high-permeability material (magnetic core) into a support body in which a winding is formed, thereby increasing the inductance. The support body is, for example, a printed circuit board (PCB) having a plurality of board layers, each of which has a winding (wire coil) formed thereon. In addition, the high-permeability material is, for example, a ferrite magnetic core. In an embodiment of the present application, the magnetic core is integrated into the printed circuit board, and the inductance device (inductor) having this architecture is referred to as a heterogeneously integrated inductance device (inductor).

[0044] The heterogeneously integrated inductor of the present application has a series equivalent inductance as shown in Equation [2] if three windings are formed in the first to third board layers, respectively.

[0045] L eq = L1 + L2 + L3 + 2 × (L 12 + L 23 + L 13 ) … [2]

[0046] where L1 to L3 are the self-inductances of the windings of the first to third board layers, L 12 , L 23 , and L 13These are the mutual inductances between the first and second plate windings, the mutual inductances between the second and third plate windings, and the mutual inductances between the first and third plate windings, respectively. As can be seen from formula [2], by increasing the coupling between the plates, the overall series inductance will be greatly increased. Here, we take three plates as an example for explanation. As the number of plates increases, the mutual inductance between the plates will increase significantly.

[0047] Furthermore, taking a heterogeneous integrated inductor with 20 windings formed on 20 layers as an example, the characteristic results of inductors without integrated magnetic cores and with integrated magnetic cores in the printed circuit board (PCB) are shown in Table 2.

[0048] Table 2

[0049] PCB with magnetic core? Copper loss (W) Inductance (nH) No 2.26 151.00 Yes 2.65 229.00

[0050] As shown in Table 2, although adding a magnetic core increases copper losses by 17.3%, it increases inductance by 51%. Therefore, it is worthwhile to increase the overall inductance at the cost of a small increase in copper losses.

[0051] The inductor device proposed in this invention avoids occupying the surface area of ​​the printed circuit board by integrating (setting) the magnetic core within the printed circuit board. Furthermore, by employing specific branch and winding configurations and layer arrangements, the inductance is increased and conductor losses (copper losses) are reduced. The branch and winding configurations, as well as the layer arrangements, of the inductor device of this invention will be described below.

[0052] Figure 2 This diagram shows the structure of the inductor device of the present invention. The inductor device 20 of the present invention includes: a support body 21, a magnetic core 22, and n branches B1 to B2. n (drawn in) Figure 3 A magnetic core 21, such as ferrite, is disposed within a support 21. The support 21 is, for example, a printed circuit board. The printed circuit board has at least k layers LL1 to LL1. k A total of k windings (w1~w1) are formed on these k layers. k ). Figure 2 The diagram is drawn using k=6 as an example, but it is not limited to this. Support 21 has branches B1 to B2. n And these branches B1 to B n They are connected in parallel. It should be noted that each branch has a winding structure ws1~ws n Furthermore, this winding structure is formed by connecting windings arranged on different plates in series. All branches B1 to B... n The winding structure ws1~ws n Then it surrounds the magnetic core 22.

[0053] the winding structure (ws1-ws n ) of each of the plurality of branches (B1-B k ) is configured by connecting a predetermined number (p) of winding in series; and p x n = k.

[0054] Since the k winding w1-w k are formed on the k plate layer LL1-LL k correspondingly, in the following description, sometimes for the sake of brevity, the winding w k may be indicated to correspond to the plate layer LL k , or the plate layer LL k may be indicated to correspond to the winding w 10 .

[0055] In addition, the number of turns (the number of coils) of the winding formed on each plate layer can be equal to 1 or greater than 1, and in the following description, it is assumed that the winding formed on each plate layer has only one turn, but it is not limited thereto.

[0056] In addition, the magnetic core 22 can be embedded in the support 21 and not exposed on the surface of the support, that is, the magnetic core is not exposed on the surface of the printed circuit board. In this way, the surface area of the printed circuit board is not occupied, and other electronic components can be used.

[0057] Figure 2 The structure shown is an example in which k is equal to 6, but it is not limited thereto. As shown in FIG. 2, the winding is provided on the six plate layers in the printed circuit board (PCB). In addition, the winding is provided on the six plate layers in the printed circuit board (PCB). Figure 2 Figure 2

[0058] Figure 3 The configuration relationship diagram of the branches and the plate layers of the inductance device 20 is shown in FIG. 3. The branch can also be referred to as a parallel branch or a current branch. Figure 2 In the embodiment shown in FIG. 4, the inductance device 20 has a first branch B1, a second branch B2, and a third branch B3; that is, the case where n = 3. In this embodiment, the predetermined number p is 2, but the predetermined number p can be greater than 2. The winding of each branch is connected in series by the predetermined number p, and the winding of each branch is connected in parallel by n.

[0059] Figure 3 Figure 3 ​​​​As is apparent, the first branch B1 has a winding structure ws1 composed of the winding w1 of the plate layer LL1 connected in series with the winding w4 of the plate layer LL4, the second branch B2 has a winding structure ws2 composed of the winding w2 of the plate layer LL2 connected in series with the winding w5 of the plate layer LL5, and the third branch B3 has a winding structure ws3 composed of the winding w3 of the plate layer LL3 connected in series with the winding w6 of the plate layer LL6. The aforementioned three winding structures ws1 to ws3 are connected in parallel with each other. When the current I flows through the inductance device 20, the currents II to I3 flow through the first to third branches (B1 to B3), respectively.

[0060] Table III Figure 3 the configuration relationship of the branches B1 to B3 and the plate layers LL1 to LL6 is as follows. This configuration relationship is also referred to as an arrangement relationship or a stacking relationship.

[0061] Table III

[0062]

[0063] As is apparent from Table III, the windings w1 and w4 in the first branch B1, the windings w2 and w5 in the second branch B2, and the windings w3 and w6 in the third branch B3 are arranged in a stacked manner in the support body 21 in such a way that they are interleaved with each other. This arrangement is hereinafter referred to as an interleaved arrangement. This interleaved arrangement is formed by connecting the winding w1 of the plate layer LL1 and the winding w2 of the plate layer LL4 in series, connecting the winding w2 of the plate layer LL2 and the winding w5 of the plate layer LL5 in series, and connecting the winding w3 of the plate layer LL3 and the winding w6 of the plate layer LL6 in series, respectively, by means of vias.

[0064] Table IV

[0065] Table IV

[0066]

[0067]

[0068] The "interleaved" arrangement in Table IV is the arrangement shown in Table III.

[0069] The "general" arrangement in Table IV is formed by connecting the winding w1 of the plate layer LL1 and the winding w2 of the plate layer LL2 in series, connecting the winding w3 of the plate layer LL3 and the winding w4 of the plate layer LL4 in series, and connecting the winding w5 of the plate layer LL5 and the winding w6 of the plate layer LL6 in series, respectively, by means of vias.

[0070] The "symmetrical" arrangement in Table 4 is to connect the winding w1 of the plate layer LL1 and the winding w5 of the plate layer LL5 in series through the via, to connect the winding w2 of the plate layer LL2 and the winding w4 of the plate layer LL4 in series, and to connect the winding w3 of the plate layer LL3 and the winding w6 of the plate layer LL6 in series, to form the 1st branch B1 to the 3rd branch B3. Since the winding w1 to w6 and the corresponding arrangement "B1-B2-B3-B2-B1-B3" of the branch have a part of the symmetrical relationship "1-2-3-2-1", it is called the symmetrical arrangement.

[0071] It is noted that, according to Table 4, the copper loss (power loss) of the interleaved inductance device is smaller than that of the symmetrical inductance device, and the copper loss of the symmetrical inductance device is smaller than that of the general inductance device. Therefore, the inductance device arranged in the interleaved manner has a lower copper loss.

[0072] Table 5 shows the four different winding arrangement modes of the inductor and the corresponding copper loss when the PCB has 12 plate layers. It is noted that there are 3 branches (B1 to B3), and the predetermined number p is 4.

[0073] Table 5

[0074]

[0075]

[0076] The "(full) interleaved", "general", and "symmetrical" arrangements in Table 5 are similar to the "interleaved", "general", and "symmetrical" arrangements in Table 4, and will not be described in detail.

[0077] The "half interleaved" arrangement in Table 5 is to connect the winding w1 and w2 of the plate layer LL1 and LL2 in series with the winding w7 and w8 of the plate layer LL7 and LL7 through the via, to connect the winding w3 and w4 of the plate layer LL3 and LL4 in series with the winding w9 and w10 of the plate layer LL9 and LL10, and to connect the winding w5 and w6 of the plate layer LL5 and LL6 in series with the winding w11 and w12 of the plate layer LL11 and LL12, to form the 1st branch B1 to the 3rd branch B3. According to Table 5, the copper loss of the inductance device arranged in the interleaved manner is still lower (2.08 W), and the copper loss of the inductance device arranged in the symmetrical manner is the second lowest (2.26 W). 10 10 11 12 11 12

[0078] ​​​​​​Table VI summarizes the four different winding configurations of the inductor when the PCB has 18 layers, and the corresponding copper losses. Note that there are three branches (Bl- B3) and the fixed number p is 6.

[0079] Table VI

[0080]

[0081]

[0082] The "general", "half-interleaved", "(full) interleaved", and "symmetric" arrangements in Table VI are similar to those in Table V and will not be described in detail.

[0083] From Table VI, it can be seen that the interleaved arrangement has the lowest copper loss (3.97 W), and the symmetric arrangement has the second lowest copper loss (4.16 W).

[0084] From Tables IV to VI, it can be seen that the interleaved arrangement generally has the lowest copper loss, and the symmetric arrangement generally has the second lowest copper loss. Therefore, the best choice for the heterogeneous integrated inductor device of the present application is the interleaved arrangement, and the second best choice is the symmetric arrangement.

[0085] Conventional inductor structures, such as inductors using E-E cores, have a design using air gaps. As a result, the imaginary impedance of the windings closer to the air gap has a clear tendency to be smaller (see Table VII). In Table VII, the imaginary impedance of the windings near layers L5, L6, and L7 is clearly smaller because the air gap is located between layers L6 and L7.

[0086] Table VII

[0087]

[0088] The core of the heterogeneous integrated inductor device of the present application has a continuous structure around the windings, so it does not have a design using air gaps. Therefore, the imaginary impedance of each winding layer is more continuous. In addition, the interleaved arrangement is used to make the impedance of the branches formed by the windings of different layers (after averaging) more consistent, thereby improving the current sharing degree and reducing the loss. Referring to Table VIII, compared with conventional inductor devices, the impedance of each winding layer changes less and is more continuous.

[0089] Table VIII

[0090]

[0091]

[0092] In summary, the (heterogeneous integrated) inductor device of the present application has at least the following features:

[0093] (1) The magnetic core is arranged in the printed circuit substrate (supporting body) to increase the inductance and reduce the loss. In addition, the magnetic core does not protrude from the surface layer of the printed circuit substrate, so as to avoid occupying the surface layer space.

[0094] (2) The winding structures of each branch are arranged in an interleaved manner to achieve current sharing and reduce loss.

[0095] (3) The winding structures of each branch are arranged in a symmetrical manner to achieve current sharing and reduce loss.

[0096] (4) The windings of different layers in each branch are connected in series, which can avoid the problem that the overall inductance of the multi-layer winding structure decreases when connected in parallel due to imperfect coupling of the traces of each layer of the printed circuit substrate.

[0097] Another embodiment of the present application discloses a power converter, comprising: a switching module; and the aforementioned inductor device, which is coupled with the switching module.

[0098] Although the present application has been disclosed as above with embodiments, it is not intended to limit the present application, and any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present application, so the protection scope of the present application shall be subject to the appended claims.

Claims

1. An inductor device, comprising: Support structure; The magnetic core is disposed on the aforementioned support. as well as Multiple branch lines are installed on the aforementioned support structure and connected in parallel with each other; Each of the aforementioned branches has a winding structure and is respectively wrapped around the aforementioned magnetic core.

2. The inductor device as claimed in claim 1, wherein, The aforementioned support body comprises multiple plates, and each of the multiple plates is provided with a winding; the winding structure of each of the multiple branches is composed of a predetermined number of the aforementioned windings connected in series; and the predetermined number of windings are arranged on different plates.

3. The inductor device as claimed in claim 2, wherein, The aforementioned multiple branches have a first branch to an nth branch, and in the first branch to the nth branch, all windings on different branches are arranged in an alternating manner.

4. The inductor device as claimed in claim 3, wherein, n is at least 2, and the aforementioned predetermined quantity is at least 2.

5. The inductor device as claimed in claim 2, wherein, The aforementioned multiple branches have a first branch to an nth branch, and the multiple windings constituting the multiple winding structures of the first branch to the nth branch are arranged in a symmetrical manner.

6. The inductor device as claimed in claim 5, wherein, Each of the first to the nth branches includes at least one winding and another winding connected in series; the symmetrical arrangement includes a configuration from one winding of the first branch to one winding of the nth branch, and from one winding of the nth branch to another winding of the first branch.

7. The inductor device as claimed in claim 3 or 5, wherein the product of the predetermined number and the number of branches is not greater than the number of the plurality of layers.

8. The inductor device as claimed in claim 7, wherein, The surface of the aforementioned support is covered by the aforementioned magnetic core.

9. The inductor device as claimed in claim 2, wherein, The aforementioned support is a multilayer printed circuit board.

10. The inductor device as claimed in claim 9, wherein, The windings in each of the aforementioned plates are made of conductors.

11. The inductor device as claimed in claim 10, wherein, The conductor mentioned above is copper.

12. The inductor device as claimed in claim 1, wherein, The portion of the magnetic core surrounded by the windings is a continuous, integral structure.

13. The inductor device as claimed in claim 1, wherein, The magnetic core is embedded in the support body.

14. A power converter, comprising: Switch module; as well as The inductor device according to claims 1 to 13 is coupled to the aforementioned switch module.

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