Switching power supply system device comprising planar-array inductor

Abstract

A switching power supply system device (80) comprises: a power conversion unit in which a plurality of power conversion circuits (81-84) are connected in parallel, each performing a switching operation, and that obtains an output voltage by combining outputs of the switching operations; a switching control circuit (800) that controls the switching operations; and a planar-array inductor (10) that constitutes a power inductor for the plurality of power conversion circuits (81-84). The planar-array inductor (10) comprises a magnetic body (100), and a plurality of winding wires formed in an array with respect to the magnetic body (100). Each of the plurality of winding wires is composed of a plurality of layers of copper-foil wires that are laminated with a non-magnetic and non-conducting adhesive layer (ADH) therebetween, the copper-foil wires that are adjacent to each other among the plurality of copper foil wires being electrically connected by means of an inter-layer via conductor. The magnetic body (100) is obtained by press-fitting and heat-curing sheets of magnetic material on the inside and outside of the plurality of winding wires, and is shaped to cover the plurality of winding wires. The switching control circuit (800) periodically changes a current peak value that flows through the plurality of winding wires during the switching operation period.

Description

Switching power supply system with planar array inductor

[0001] The present invention relates to a switching power supply system device including a plurality of inductors and a plurality of power conversion circuits each including one of the plurality of inductors.

[0002] Patent Document 1 describes an M-phase coupled inductor. The M-phase coupled inductor in Patent Document 1 includes a ladder-shaped magnetic core having multiple rectangular parallelepiped inner legs and multiple windings wound around the inner legs. Gaps are provided between the multiple inner legs.

[0003] Patent Document 2 describes a switching power supply system. The switching power supply system of Patent Document 2 includes a plurality of switching circuit units and a control unit. Each of the plurality of switching circuit units includes an inductor.

[0004] The multiple inductors that make up the switching circuit section each include multiple windings formed on a multilayer printed circuit board and magnetic sheets that are arranged to sandwich the multilayer printed circuit board.

[0005] U.S. Patent No. 8,294,544 International Publication No. 2020 / 035967

[0006] In the case of a ladder-type core such as that disclosed in Patent Document 1, when increasing the number of coupled inductors, the inductors must be arranged horizontally or vertically, resulting in a complex shape. Also, in the case of a ladder-type core, the winding structure becomes more complex as the number of coupled inductors increases.

[0007] Furthermore, in the case of a ladder-type core as in Patent Document 1, or in the case of multiple windings sandwiched between magnetic sheets as in Patent Document 2, small spaces are formed between the multiple windings and the magnetic material (magnetic body or magnetic sheet). These spaces have low relative permeability and high thermal resistance. Therefore, if the magnetic flux density is increased in these structures, the volume of the inductor will increase.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a switching power supply system equipped with a thin planar array inductor that can suppress localized heat generation and localized increases in magnetic flux density.

[0009] A switching power supply system device equipped with a planar array inductor of the present invention comprises a power conversion section that connects a plurality of power conversion circuits in parallel and combines the currents output by each switching operation to obtain an output voltage, a switching control circuit that controls the switching operation, and a planar array inductor that includes a plurality of power inductors that make up the plurality of power conversion circuits.

[0010] The planar array inductor includes a planar core and multiple windings arranged around the planar core. Each of the multiple windings uses multiple layers of copper foil wiring laminated with a nonmagnetic and nonconductive adhesive layer sandwiched therebetween, and adjacent copper foil wirings are electrically connected using interlayer via conductors. The planar core is shaped to cover the multiple windings, and sheet-like magnetic material is crimped and heat-cured on the inside and outside of the multiple windings. The switching control circuit controls the entire periodic switching operation by sequentially shifting the windings that have the peak current values ​​flowing through them over time during an entire switching cycle for a series of switching operations based on each switching operation, and also periodically shifts the position and time in the planar core where the magnetic flux generated by the currents in the multiple windings achieves the maximum magnetic flux density.

[0011] In this configuration, the heat generated in the planar core and the multiple windings is integrated using thermal conduction and uniformly distributed across the plane, suppressing local increases in magnetic flux density and local heat generation in the planar core.

[0012] According to the present invention, in a switching power supply system device including a planar array inductor, it is possible to suppress localized heat generation and localized increases in magnetic flux density while realizing a thin design.

[0013] FIG. 1 is a perspective view of a planar array inductor according to a first embodiment of the present invention. FIG. 2 is a perspective view of multiple windings of the planar array inductor according to the first embodiment of the present invention. FIG. 3 is a perspective view of one inductor constituting the planar array inductor according to the first embodiment of the present invention. FIG. 4 is an exploded perspective view of one inductor constituting the planar array inductor according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of the planar array inductor according to the first embodiment of the present invention. FIGS. 6(A), 6(B), 6(C), 6(D), and 6(E) are side cross-sectional views showing the state at each step in the manufacturing process of the planar array inductor according to the first embodiment of the present invention. FIG. 7 is an equivalent circuit diagram of a switching power supply system according to the first embodiment of the present invention. FIG. 8 is a graph showing the time change in output current value when multiphase control is performed and when it is not performed. FIG. 9 is an exploded perspective view showing an example of the structure of the switching power supply system according to the first embodiment of the present invention. FIG. 10 is a perspective view of multiple windings of a planar array inductor according to a second embodiment of the present invention. FIG. 11 is an exploded perspective view of one inductor constituting the planar array inductor according to the second embodiment of the present invention.

[0014] First Embodiment A switching power supply system including a planar array inductor according to a first embodiment of the present invention will be described with reference to the drawings.

[0015] (Planar Array Inductor) Fig. 1 is a perspective view of a planar array inductor according to a first embodiment of the present invention. Fig. 2 is a perspective view of a plurality of windings of the planar array inductor according to the first embodiment of the present invention. Fig. 3 is a perspective view of one inductor constituting the planar array inductor according to the first embodiment of the present invention. Fig. 4 is an exploded perspective view of one inductor constituting the planar array inductor according to the first embodiment of the present invention. Fig. 5 is a cross-sectional view of the planar array inductor according to the first embodiment of the present invention. Fig. 5 shows A-A shown in Figs. 1 and 3. Note that in each figure, the three orthogonal axes are referred to as the X-axis, Y-axis, and Z-axis, but these are names of axes used to facilitate explanation and do not limit, for example, the direction in which the planar array inductor 10 is used.

[0016] 1, 2, 3, 4, and 5, the planar array inductor 10 includes an inductor 11, an inductor 12, an inductor 13, and an inductor 14. In this embodiment, an example is shown in which the planar array inductor 10 is composed of four inductors 11-14, but the number is not limited to four as long as there is a plurality of inductors.

[0017] The planar array inductor 10 includes a magnetic material 100. The planar array inductor 10 includes a plurality of winding conductors 111, 112 and an interlayer via conductor 119 that constitute the inductor 11, a plurality of winding conductors 121, 122 and an interlayer via conductor 129 that constitute the inductor 12, a plurality of winding conductors 131, 132 and an interlayer via conductor 139 that constitute the inductor 13, and a plurality of winding conductors 141, 142 and an interlayer via conductor 149 that constitute the inductor 14.

[0018] The planar array inductor 10 includes a plurality of external terminals P101, P102 for the inductor 11, a plurality of external terminals P201, P202 for the inductor 12, a plurality of external terminals P301, P302 for the inductor 13, and a plurality of external terminals P401, P402 for the inductor 14. The planar array inductor 10 includes external connection via conductors Via101, Via102 for the inductor 11, external connection via conductors Via201, Via202 for the inductor 12, external connection via conductors Via301, Via302 for the inductor 13, and external connection via conductors Via401, Via402 for the inductor 14.

[0019] 3 and 4, the winding conductors 111 and 112 are wound in a substantially complete circle. The winding conductors 111 and 112 are formed from linear (strip) copper foil having a predetermined width.

[0020] The winding conductors 111 and 112 are stacked so that their planes are parallel to each other, and are arranged so that the winding conductors 111 and 112 face each other over substantially the entire circumference.

[0021] The winding conductors 111 and 112 are arranged with an adhesive layer ADH (see FIG. 5 ) sandwiched therebetween, and the adhesive layer ADH bonds the winding conductors 111 and 112 together. In this case, the adhesive layer ADH is arranged over substantially the entire surface where the winding conductors 111 and 112 face each other. The adhesive layer ADH is made of a non-magnetic and non-conductive (insulating) material.

[0022] An external connection pad conductor 113 is connected to one end of the winding conductor 111. The other end of the winding conductor 111 is connected to one end of the winding conductor 112 through the interlayer via conductor 119. This electrically connects the winding conductors 111 and 112 via the interlayer via conductor 119. An external connection pad conductor 114 is connected to the other end of the winding conductor 112. With this configuration, the inductor 11 achieves a thin helical winding having the pad conductor 113 at one end and the pad conductor 114 at the other end.

[0023] The helical winding of the inductor 11 is covered with the magnetic material 100. More specifically, the magnetic material 100 is filled inside and outside the helical winding of the inductor 11, and has a shape that does not have any air gaps.

[0024] The magnetic body 100 is formed using, for example, a metal composite type magnetic material (metal composite material). More specifically, the magnetic material of the magnetic body 100 is a thermosetting resin containing a plurality of metallic magnetic particles covered with an insulating resin film such as an epoxy resin.

[0025] The magnetic body 100 has a main surface F101 and a main surface F102. A plurality of external terminals P101 and P102 are formed on the main surface F101 of the magnetic body 100. The external terminals P101 and P102 are, for example, rectangular in plan view (Z-axis direction). The external terminals P101 and P102 correspond to "external electrodes" of the present invention. The external terminals P101 and P102 are formed by metal plating using gold (Au) or nickel (Ni).

[0026] The pad conductor 113 is connected to an external terminal P101 through an external connection via conductor Via101 formed in the magnetic body 100. The pad conductor 114 is connected to an external terminal P102 through an external connection via conductor Via102 formed in the magnetic body 100. The external connection via conductor Via101 is formed integrally with the external terminal P101, for example, and the external connection via conductor Via102 is formed integrally with the external terminal P102.

[0027] With this configuration, inductor 11 realizes a planar inductor having a planar core whose thickness (the dimension in the Z-axis direction in the figure) is smaller than the dimensions in other directions (the dimensions in the X-axis and Y-axis directions in the figure) that make up the surface on which the winding conductors are formed.

[0028] (Multiple Inductors 12, 13, 14) The basic configuration of the multiple inductors 12, 13, 14 is similar to that of the inductor 11. Therefore, the configuration of the multiple inductors 12, 13, 14 will be described briefly.

[0029] (Inductor 12) Winding conductor 121 and winding conductor 122 are laminated and connected by interlayer via conductor 129. This realizes a helical winding in inductor 12. The helical winding of inductor 12 is covered with magnetic body 100.

[0030] One end of the winding conductor 121 is connected to an external terminal P201 through a pad conductor 123 and an external connection via conductor Via201. The other end of the winding conductor 122 is connected to an external terminal P202 through a pad conductor 124 and an external connection via conductor Via202.

[0031] (Inductor 13) Winding conductor 131 and winding conductor 132 are laminated and connected by interlayer via conductor 139. This realizes a helical winding in inductor 13. The helical winding of inductor 13 is covered with magnetic body 100.

[0032] One end of the winding conductor 131 is connected to an external terminal P301 through a pad conductor 133 and an external connection via conductor Via301. The other end of the winding conductor 132 is connected to an external terminal P302 through a pad conductor 134 and an external connection via conductor Via302.

[0033] (Inductor 14) Winding conductor 141 and winding conductor 142 are laminated and connected by interlayer via conductor 149. This realizes a helical winding in inductor 14. The helical winding of inductor 14 is covered with magnetic body 100.

[0034] One end of the winding conductor 141 is connected to an external terminal P401 through a pad conductor 143 and an external connection via conductor Via401. The other end of the winding conductor 142 is connected to an external terminal P402 through a pad conductor 144 and an external connection via conductor Via402.

[0035] (Overall configuration of planar array inductor 10) The helical windings of the above-mentioned inductor 11, the helical windings of the inductor 12, the helical windings of the inductor 13, and the helical windings of the inductor 14 are arranged at intervals in a direction (X-axis direction in the figure) perpendicular to the direction in which each of the multiple windings is stacked (Z-axis direction in the figure).

[0036] The helical winding of inductor 11, the helical winding of inductor 12, the helical winding of inductor 13, and the helical winding of inductor 14 arranged in this manner are covered with magnetic body 100. As a result, the multiple inductors 11, 12, 13, and 14 have a structure in which they are arranged side by side in a plane in a direction perpendicular to the thickness direction of magnetic body 100, which is a planar core. Therefore, planar array inductor 10 has a thin outer shape.

[0037] 1 , the magnetic body 100 is a flat plate whose thickness dimension (length in the Z-axis direction) is shorter than its dimensions in other directions (lengths in the X-axis direction and the Y-axis direction). The magnetic body 100 has main surfaces F101 and F102 orthogonal to the thickness direction, side surfaces F103 and F104 on both sides of the direction in which the multiple inductors 11, 12, 13, and 14 are arranged, and side surfaces F105 and F106 orthogonal to the main surfaces F101, F102, F103, and F104. The helical windings of the inductors 11, 12, 13, and 14 are arranged side by side between the side surfaces F103 and F104 in a direction parallel to the main surfaces F101 and F102.

[0038] In this configuration, the helical winding of inductor 11, the helical winding of inductor 12, the helical winding of inductor 13, and the helical winding of inductor 14 are covered by magnetic body 100, which has no local air gaps. In other words, there are no air gaps within magnetic body 100, and further, there are no air gaps between magnetic body 100 and each of the winding conductors of the multiple inductors 11, 12, 13, and 14 and magnetic body 100. More specifically, there is no air gap between magnetic body 100 and each of the winding conductors of the multiple inductors 11, 12, 13, and 14 on both the inside and outside of each of the winding conductors of the multiple inductors 11, 12, 13, and 14, and magnetic body 100 is in close contact with inductors 11, 12, 13, and 14.

[0039] This makes it possible to prevent the relative permeability from being locally reduced in the planar array inductor 10. Therefore, even if the planar array inductor 10 is small and thin, the inductance of the plurality of inductors 11, 12, 13, and 14 can be increased.

[0040] Furthermore, the planar array inductor 10 does not have any areas with locally high thermal resistance. Furthermore, since the magnetic body 100 is a metal composite type magnetic material, the planar array inductor 10 has excellent thermal conductivity and can keep thermal resistance low. As a result, heat generated by current flowing through the multiple inductors 11, 12, 13, and 14 of the planar array inductor 10 does not remain localized, but is diffused throughout the magnetic body 100. As a result, the planar array inductor 10 can suppress localized heat generation.

[0041] Furthermore, in this configuration, for example, when the number of inductors is increased, it is only necessary to increase the number of inductors arranged in a plane and increase the area of ​​the magnetic body 100 accordingly. On the other hand, when the number of inductors is reduced, it is only necessary to decrease the number of inductors arranged in a plane and decrease the area of ​​the magnetic body 100 accordingly. Therefore, the shape of the planar array inductor 10 does not become complicated when the number of inductors is changed.

[0042] The helical windings of inductors 11, 12, 13, and 14 are arranged so that the ends connected to their respective external terminals are on the same side relative to each other.

[0043] (Manufacturing method of planar array inductor 10) Figures 6(A), 6(B), 6(C), 6(D), and 6(E) are side cross-sectional views showing the state at each step in the manufacturing process of the planar array inductor according to the first embodiment of the present invention. Note that in this embodiment, one planar array inductor is illustrated. However, in actual manufacturing, multiple planar array inductors are formed and then singulated in a so-called multi-state in which multiple planar array inductors can be formed. Also, although only the inductor 11 is shown in Figures 6(A) to 6(E), the inductors 12, 13, and 14 are also formed together with the inductor 11.

[0044] 6A, the copper foil M101 and the copper foil M102 are bonded together with a non-magnetic and non-conductive adhesive layer (adhesive material) ADH, for example, by using a vacuum press.

[0045] Here, by making the adhesive layer ADH thinner than the copper foils M101 and M102, the copper foils M101 and M102 are bonded together with a low gap GAP, and the winding conductors 111 and 112 of the inductor 11 are fixed and positioned with a low gap GAP.

[0046] 6B, a recess H119 is formed through the copper foil M102 and the adhesive layer ADH. The recess H119 is formed in the copper foil M102 by laser processing, and in the adhesive layer ADH by etching.

[0047] 6C, electrolytic plating is performed to fill the recesses H119 with copper, thereby forming interlayer via conductors 119.

[0048] As shown in Figure 6 (D), a helical winding in which the winding conductor 111 and the winding conductor 112 are bonded together by the adhesive layer ADH is formed by performing pattern etching on a laminate in which the copper foil M101 and the copper foil M102 are bonded together by the adhesive layer ADH.

[0049] As shown in Fig. 6(E), a sheet of thermosetting magnetic material is pressed and heated to harden it (using a hot vacuum press) so as to cover the helical winding. This hardens the magnetic material to a high density, forming a magnetic body 100 (flat core) that is tightly adhered to both the inside and outside of the helical winding.

[0050] After this, although not shown in the figure, laser processing is performed on the magnetic body 100 to form holes for external connection via conductors, and copper plating, nickel plating, and Au plating are performed to fill these holes, thereby forming external connection via conductors Via101, Via102, and external terminals P101 and P102.

[0051] (Switching power supply system 80) Fig. 7 is an equivalent circuit diagram of the switching power supply system according to the first embodiment of the present invention. As shown in Fig. 7, the switching power supply system 80 includes a planar array inductor 10 which is a power inductor, a switching control circuit 800, a power conversion circuit 81, a power conversion circuit 82, a power conversion circuit 83, a power conversion circuit 84, and a capacitor 88.

[0052] A DC power supply is connected between the high-side power supply input terminal and the low-side power supply input terminal of the switching power supply system device 80. The high-side power supply input terminal is connected to the positive electrode of the DC power supply, and the low-side power supply input terminal is connected to the negative electrode of the DC power supply.

[0053] In general, the switching power supply system 80 configures a power conversion section by connecting a plurality of power conversion circuits 81-84 in parallel, and obtains an output voltage by combining outputs from the respective power conversion circuits 81-84 that are subjected to switching operations.

[0054] The power conversion circuit 81 includes a driver circuit 810, a switching element Q81H, a switching element Q81L, and the inductor 11 of the planar array inductor 10. The driver circuit 810 is realized by an analog IC. The switching element Q81H and the switching element Q81L are power semiconductor elements, such as power MOSFETs.

[0055] The driver circuit 810 is connected to the gate terminal of the switching element Q81H and the gate terminal of the switching element Q81L. The driver circuit 810 controls the switching of the switching element Q81H and the switching element Q81L based on a control signal for the power conversion circuit 81 (for the driver circuit 810) from the switching control circuit 800.

[0056] The drain terminal of switching element Q81H is connected to the high-side power supply input terminal of switching power supply system 80. The source terminal of switching element Q81H is connected to the drain terminal of switching element Q81L. The source terminal of switching element Q81L is connected to the low-side power supply input terminal (terminal connected to the reference potential line) of switching power supply system 80. The reference potential line connects the low-side power supply input terminal (terminal connected to the negative pole of the DC power supply) of switching power supply system 80 to the low-side output terminal of switching power supply system 80 (terminal connected to the negative pole of load 89).

[0057] The node between the source terminal of the switching element Q81H and the drain terminal of the switching element Q81L is connected to an external terminal P101 of the planar array inductor 10. The external terminal P101 is connected to one terminal of the inductor 11. The other terminal of the inductor 11 is connected to an external terminal P102.

[0058] The power conversion circuit 82 includes a driver circuit 820, a switching element Q82H, a switching element Q82L, and the inductor 12 of the planar array inductor 10. The driver circuit 820 is realized by an analog IC. The switching element Q82H and the switching element Q82L are power semiconductor elements, such as power MOSFETs.

[0059] The driver circuit 820 is connected to the gate terminal of the switching element Q82H and the gate terminal of the switching element Q82L. The driver circuit 820 controls the switching of the switching element Q82H and the switching element Q82L based on a control signal for the power conversion circuit 82 (for the driver circuit 820) from the switching control circuit 800.

[0060] The drain terminal of switching element Q82H is connected to the high-side power supply input terminal of switching power supply system 80. The source terminal of switching element Q82H is connected to the drain terminal of switching element Q82L. The source terminal of switching element Q82L is connected to the low-side power supply input terminal of switching power supply system 80 (the terminal connected to the reference potential line).

[0061] The node between the source terminal of the switching element Q82H and the drain terminal of the switching element Q82L is connected to an external terminal P201 of the planar array inductor 10. The external terminal P201 is connected to one terminal of the inductor 12. The other terminal of the inductor 12 is connected to an external terminal P202.

[0062] The power conversion circuit 83 includes a driver circuit 830, a switching element Q83H, a switching element Q83L, and the inductor 13 of the planar array inductor 10. The driver circuit 830 is realized by an analog IC. The switching element Q83H and the switching element Q83L are power semiconductor elements, such as power MOSFETs.

[0063] Driver circuit 830 is connected to the gate terminal of switching element Q83H and the gate terminal of switching element Q83L. Driver circuit 830 controls the switching of switching element Q83H and switching element Q83L based on a control signal for power conversion circuit 83 (for driver circuit 830) from switching control circuit 800.

[0064] The drain terminal of switching element Q83H is connected to the high-side power supply input terminal of switching power supply system 80. The source terminal of switching element Q83H is connected to the drain terminal of switching element Q83L. The source terminal of switching element Q83L is connected to the low-side power supply input terminal of switching power supply system 80 (the terminal connected to the reference potential line).

[0065] The node between the source terminal of the switching element Q83H and the drain terminal of the switching element Q83L is connected to an external terminal P301 of the planar array inductor 10. The external terminal P301 is connected to one terminal of the inductor 13. The other terminal of the inductor 13 is connected to an external terminal P302.

[0066] The power conversion circuit 84 includes a driver circuit 840, a switching element Q84H, a switching element Q84L, and the inductor 14 of the planar array inductor 10. The driver circuit 840 is realized by an analog IC. The switching element Q84H and the switching element Q84L are power semiconductor elements, such as power MOSFETs.

[0067] Driver circuit 840 is connected to the gate terminal of switching element Q83 H and the gate terminal of switching element Q84 L. Driver circuit 840 controls the switching of switching element Q84 H and switching element Q84 L based on a control signal for power conversion circuit 84 (for driver circuit 840) from switching control circuit 800.

[0068] The drain terminal of switching element Q84H is connected to the high-side power supply input terminal of switching power supply system 80. The source terminal of switching element Q84H is connected to the drain terminal of switching element Q84L. The source terminal of switching element Q84L is connected to the low-side power supply input terminal of switching power supply system 80 (the terminal connected to the reference potential line).

[0069] The node between the source terminal of the switching element Q84H and the drain terminal of the switching element Q84L is connected to an external terminal P401 of the planar array inductor 10. The external terminal P401 is connected to one terminal of the inductor 14. The other terminal of the inductor 14 is connected to an external terminal P402.

[0070] The external terminal P102, the external terminal P202, the external terminal P302, and the external terminal P402 are connected together, and this node is connected to the Hi-side output terminal of the switching power supply system device 80.

[0071] The capacitor 88 is a smoothing capacitor and is connected between the high-side output terminal and the low-side output terminal connected to the reference potential line.

[0072] (Operation of Switching Power Supply System Apparatus 80) In this configuration, the switching control circuit 800 performs multiphase control according to the output voltage and output current to the load 89. More specifically, the switching control circuit 800 selects a power conversion circuit to be driven according to the output voltage and output current. The switching control circuit 800 generates a control signal to sequentially drive the power conversion circuits to be driven according to the switching operation cycle of the switching elements of the power conversion circuits to be driven.

[0073] By performing such multiphase control, switching power supply system apparatus 80 can periodically change, in the switching operation cycle, the peak value of the current flowing through the multiple windings that make up each of the multiple inductors 11, 12, 13, and 14. Furthermore, switching power supply system apparatus 80 can periodically move, within magnetic body 100, the position and time at which the magnetic flux density becomes maximum due to the magnetic flux created by the currents in the multiple windings that make up each of the multiple inductors 11, 12, 13, and 14 in magnetic body 100.

[0074] As a result, the switching power supply system 80 equipped with the planar array inductor 10 can uniformly distribute the heat generated in the magnetic body 100 and the multiple windings that make up each of the multiple inductors 11, 12, 13, and 14 in a plane while integrating the heat through thermal conduction. Therefore, the switching power supply system 80 equipped with the planar array inductor 10 can suppress a local increase in magnetic flux density in the magnetic body 100, despite being thin.

[0075] In particular, since the planar array inductor 10 does not have any internal voids, local heat generation can be more effectively suppressed, and an increase in local magnetic flux density in the magnetic body 100 can be more effectively suppressed.

[0076] By being provided with the above configuration, the switching power supply system 80 including the planar array inductor 10 can suppress heat generation, suppress output voltage ripple in the switching power supply system 80, and suppress the generation of electromagnetic noise due to changes in the current peak value. Therefore, the switching power supply system 80 including the planar array inductor 10 can realize a highly efficient, high-performance switching power supply system that suppresses heat generation.

[0077] Furthermore, by performing multiphase control, the switching power supply system 80 can achieve the following advantageous effects. Fig. 8 is a graph showing the change in output current value over time when multiphase control is performed and when it is not performed. In Fig. 8, the solid line shows the case when multiphase control is performed, and the dashed line shows the case when multiphase control is not performed.

[0078] 8, the peak value of the current can be lowered and the difference between the maximum and minimum values ​​of the current can be reduced compared to when multiphase control is not performed. Therefore, the planar array inductor 10 can further suppress heat generation and output voltage ripple.

[0079] (Structure of Switching Power Supply System Apparatus 80) FIG. 9 is an exploded perspective view showing an example of the structure of a switching power supply system apparatus according to the first embodiment of the present invention.

[0080] 9, a switching power supply system 80 includes a heat sink HS, a semiconductor substrate SS, an insulating layer LYIN1, a control circuit layer LYCC, an insulating layer LYIN2, a planar array inductor 10, an insulating layer LYIN3, a power device layer LYPD, and a passivation layer LYPS, which are stacked in this order. A switching control circuit 800 and a plurality of driver circuits 810, 820, 830, and 840 are formed in the control circuit layer LYCC. Switching elements of a plurality of power conversion circuits 81, 82, 83, and 84 are formed in the power device layer LYPD.

[0081] In this way, the switching power supply system 80 is realized in a shape in which a plurality of functional layers are stacked. In this case, the plurality of inductors 11, 12, 13, and 14 are formed by the planar array inductor 10, so that the switching power supply system 80 can realize a structure in which a plurality of functional layers are stacked.

[0082] This structure allows the switching power supply system 80 to have a small planar area.

[0083] Although the planar array inductor 10 described above uses a winding conductor that is substantially rectangular in plan view, the planar shape of the winding conductor is not limited to this. For example, the planar shape of the winding conductor may be circular or the like.

[0084] Second Embodiment A switching power supply system including a planar array inductor according to a second embodiment of the present invention will be described with reference to the drawings.

[0085] Fig. 10 is a perspective view of a plurality of windings of a planar array inductor according to a second embodiment of the present invention. Fig. 11 is an exploded perspective view of one inductor constituting the planar array inductor according to the second embodiment of the present invention.

[0086] 10 and 11, the planar array inductor 10A according to the second embodiment differs from the planar array inductor 10 according to the first embodiment in the shape of the winding conductor. Other configurations of the planar array inductor 10A are similar to those of the planar array inductor 10, and descriptions of similar parts will be omitted.

[0087] The planar array inductor 10A includes a plurality of inductors 11A, 12A, 13A, and 14A. The plurality of inductors 11A, 12A, 13A, and 14A are so-called center-tapped windings.

[0088] The winding portion of the inductor 11A includes a winding conductor 111A and a winding conductor 112A. The winding conductors 111A and 112A are formed by a central conductor and two winding conductors arranged on either side of it. The winding conductors 111A and 112A are connected by an interlayer via conductor 119A. The winding conductors 111A and 112A are stacked and bonded with a small gap by an adhesive (not shown). A pad conductor 113A is connected to the winding conductor 111A, and a pad conductor 114A is connected to the winding conductor 112A.

[0089] The winding portion of the inductor 12A includes a winding conductor 121A, a winding conductor 122A, an interlayer via conductor 129A, a pad conductor 123A, and a pad conductor 124A, and has the same configuration as the winding portion of the inductor 11A.

[0090] The winding portion of the inductor 13A includes a winding conductor 131A, a winding conductor 132A, an interlayer via conductor 139A, a pad conductor 133A, and a pad conductor 134A, and has the same configuration as the winding portion of the inductor 11A.

[0091] The winding portion of the inductor 14A includes a winding conductor 141A, a winding conductor 142A, an interlayer via conductor 149A, a pad conductor 143A, and a pad conductor 144A, and has the same configuration as the winding portion of the inductor 11A.

[0092] The windings of inductors 11A, 12A, 13A, and 14A are arranged in a plane as shown in Fig. 10. The windings of inductors 11A, 12A, 13A, and 14A are covered by a magnetic body (planar core) (not shown). There are no air gaps inside the magnetic body.

[0093] With this configuration, the planar array inductor 10A can achieve the same effects as the planar array inductor 10. Furthermore, since the planar array inductor 10A has a center-tapped winding, magnetic coupling between adjacent windings can be suppressed. Therefore, the planar array inductor 10A can shorten the distance between adjacent windings, and can have a small planar shape.

[0094] <1> A switching power supply system device including a planar array inductor, the planar array inductor including: a power conversion unit that connects a plurality of power conversion circuits in parallel and combines currents output by the switching operations of the respective power conversion circuits to obtain an output voltage; a switching control circuit that controls the switching operations; and a planar array inductor that includes a plurality of power inductors that constitute the plurality of power conversion circuits, the planar array inductor including: a planar core; and a plurality of windings that are arranged on the planar core, each of the plurality of windings using a plurality of layered copper foil wirings that are laminated with a non-magnetic and non-conductive adhesive layer sandwiched therebetween, and adjacent copper foil wirings among the plurality of copper foil wirings are electrically connected using interlayer via conductors, the planar core is shaped to cover the plurality of windings and is in close contact with the inside and outside of the plurality of windings, and the switching control circuit controls the periodic overall switching operation by sequentially shifting the windings that reach the current peak value over time during an overall switching period for a series of switching operations based on the respective switching operations, and periodically shifting the position and time in the planar core at which the magnetic flux created by the currents in the plurality of windings provides the maximum magnetic flux density, A switching power supply system device equipped with a planar array inductor that uses thermal conduction to integrate the heat generated in the planar core and the multiple windings and distributes the heat uniformly across a plane, thereby suppressing local increases in magnetic flux density and local heat generation in the planar core.

[0095] <2> A switching power supply system device including the planar array inductor according to <1>, wherein the sheet-like magnetic material is a metal composite material.

[0096] <3> A switching power supply system device comprising the planar array inductor of either <1> or <2>, wherein the planar array inductor has laser vias formed in the sheet-like magnetic material and external electrodes formed by metal plating.

[0097] <4> A switching power supply system device including the planar array inductor according to <3>, wherein the external electrodes are plated with gold or nickel.

[0098] <5> A switching power supply system device including the planar array inductor according to any one of <1> to <4>, wherein the plurality of windings are center-tapped windings.

[0099] <6> A switching power supply system including the planar array inductor according to any one of <1> to <4>, wherein the plurality of windings are helical windings.

[0100] <7> A switching power supply system including the planar array inductor according to any one of <1> to <6>, wherein the interlayer via conductors are copper foil.

[0101] <8> A switching power supply system device including a planar array inductor according to any one of <1> to <7>, wherein the planar core includes: a thermosetting resin base material; and a plurality of magnetic particles mixed into the resin base material, each of which is covered with an insulating resin.

[0102] <9> A switching power supply system device including a planar array inductor according to any one of <1> to <8>, wherein the planar core is formed by crimping and heat-hardening a sheet-like magnetic material on the inside and outside of the plurality of windings.

[0103] <10> A switching power supply system device including the planar array inductor according to any one of <1> to <9>, wherein the switching control circuit controls the current flowing through the plurality of windings by multiphase control of the output current.

[0104] 10, 10A: Planar array inductor 11, 11A, 12, 12A, 13, 13A, 14, 14A: Inductor 80: Switching power supply system device 81, 82, 83, 84: Power conversion circuit 88: Capacitor 89: Load 100: Magnetic material 111, 111A, 112, 112A, 121, 121A, 122, 122A, 131, 131A, 132, 132A, 141, 141A, 142, 142A: Winding conductor 113, 113A, 114, 114A, 123, 123A, 124, 124A, 133, 133A, 134, 134A, 143, 143A, 144, 144A: Pad conductor 119, 119A, 129, 129A, 139, 139A, 149, 149A: Interlayer via conductor 800: Switching control circuit 810, 820, 830, 840: Driver circuit ADH: Adhesive layer H119: Recess HS: Heat sink LYCC: Control circuit layer LYIN1, LYIN2, LYIN3: Insulation layer LYPD: Power device layer LYPS: Passivation layer M101, M102: Copper foil P101, P102, P201, P202, P301, P302, P401, P402: External terminals Q81H, Q81L, Q82H, Q82L, Q83H, Q83L, Q84H, Q84L: Switching elements SS: Semiconductor substrate Via101, Via102, Via201, Via202, Via301, Via302, Via401, Via402: external connection via conductors

Claims

1. a power conversion unit that connects a plurality of power conversion circuits in parallel and combines currents output by switching operations of the respective power conversion circuits to obtain an output voltage; A switching control circuit for controlling the switching operation; A planar array inductor including a plurality of power inductors that configure the plurality of power conversion circuits; In a switching power supply system device having a planar array inductor, The planar array inductor comprises: A planar core; A plurality of windings arranged on the planar core; Equipped with Each of the plurality of windings is configured to use a plurality of layered copper foil wirings laminated with a non-magnetic and non-conductive adhesive layer sandwiched therebetween, and adjacent copper foil wirings in the plurality of copper foil wirings are electrically connected to each other using interlayer via conductors; the planar core is shaped to cover the plurality of windings and is in close contact with the inside and outside of the plurality of windings, The switching control circuit includes: In an entire switching period for a series of switching operations based on the respective switching operations, the peak value of a current flowing through the plurality of windings is shifted sequentially over time to control the entire periodic switching operation, and the position and time at which the magnetic flux density becomes maximum due to the magnetic flux generated by the currents of the plurality of windings is shifted periodically in the planar core; The heat generated in the planar core and the plurality of windings is integrated by thermal conduction and uniformly distributed in a plane, thereby suppressing a local increase in magnetic flux density and local heat generation in the planar core. A switching power supply system device equipped with a planar array inductor.

2. The sheet-like magnetic material constituting the planar core is a metal composite material. A switching power supply system comprising the planar array inductor according to claim 1.

3. The planar array inductor has laser vias formed in a sheet-like magnetic material constituting the planar core, and external electrodes formed by metal plating.

3. A switching power supply system comprising the planar array inductor according to claim 1.

4. The external electrodes are plated with gold or nickel. A switching power supply system comprising the planar array inductor according to claim 3.

5. The plurality of windings are center tapped windings.

3. A switching power supply system comprising the planar array inductor according to claim 1.

6. the plurality of windings are helical windings; 3. A switching power supply system comprising the planar array inductor according to claim 1.

7. The interlayer via conductor is a copper foil.

3. A switching power supply system comprising the planar array inductor according to claim 1.

8. The planar core is A thermosetting resin substrate; A plurality of magnetic particles that are mixed into the resin base material and each of which is covered with an insulating resin; Equipped with 3. A switching power supply system comprising the planar array inductor according to claim 1.

9. The planar core is formed by pressing and heat-hardening a sheet-shaped magnetic material on the inside and outside of the plurality of windings.

3. A switching power supply system comprising the planar array inductor according to claim 1.

10. The switching control circuit includes: controlling current flowing through the plurality of windings by multi-phase control of output current; 3. A switching power supply system comprising the planar array inductor according to claim 1.