Switching power supply device with composite power inductor

Abstract

A switching power supply device (80) provided with a composite power inductor (10) is provided with a linear inductor conductor (31), a linear inductor conductor (32), an inductor conductor (33), and one magnetic body (20) that forms a magnetic path for magnetic flux generated by current flowing through the inductor conductor (31), the inductor conductor (32), and the inductor conductor (33). One end of the inductor conductor (31) is connected to the first input terminal and the other end is connected to one end of the inductor conductor (33), and one end of the inductor conductor (32) is connected to the second input terminal and the other end is connected to one end of the inductor conductor (33). The inductor conductor (31), the inductor conductor (32), and the inductor conductor (33) are sandwiched by the magnetic body (20) or included inside the magnetic body (20). The inductor conductor (31) and the inductor conductor (32) are arranged in parallel so that magnetic fluxes generated by currents flowing through the respective conductors are cancelled out in an inner leg portion (10ZI) between the inductor conductor (31) and the inductor conductor (32) in the magnetic body (20), and so that magnetic fluxes generated by currents flowing through the respective conductors are cancelled out in outer leg portions (10ZO1, 10ZO2) on the outside of the inductor conductor (31) and the inductor conductor (32) in the magnetic body (20), and the magnetic fluxes generated by currents flowing through the respective conductors are cancelled out in the outer leg portions (10ZO1, 10ZO2) on the outside of the inductor conductor (31) and the inductor conductor (32). Magnetic fluxes generated by currents flowing through the conductors are mutually enhanced. The inductor conductor (33) is disposed such that a plane formed by a magnetic flux generated by a current flowing through the conductor and a plane formed by a magnetic flux generated by a current flowing through the inductor conductor (31) and the inductor conductor (32) are orthogonal to each other. The inductor conductor (31) and the inductor conductor (32) are inductors constituting the power conversion circuit, and the inductor conductor (33) is an inductor constituting a low-pass filter for the output current of the power conversion circuit.

Description

Technical Field

[0001] The present invention relates to a switching power supply device including a composite power inductor. Background Art

[0002] Patent Document 1 discloses a ferrite laminate component including a coil conductor and a magnetic body. The ferrite laminate component of Patent Document 1 includes an inductor with a center tap and three terminals (a first terminal, a second terminal, and a third terminal).

[0003] The first terminal is connected to a center tap of the inductor, the second terminal is connected to one end of the inductor, and the third terminal is connected to the other end of the inductor.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2007-194474 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, in the structure described in Patent Document 1, when it is necessary to connect an inductor to the center tap in the circuit, the ferrite laminate component must include a separate inductor element.

[0009] For example, in order to suppress output ripple noise in a switching power supply device having a plurality of power conversion circuits, it is necessary to provide a filter circuit at the output terminals of the plurality of power conversion circuits. However, if this is to be achieved using the structure of Patent Document 1, the inductors of the plurality of power conversion circuits and the inductors of the filter circuit (output filter circuit) must be provided separately. Therefore, the number of components constituting the switching power supply device increases, and the device becomes physically larger.

[0010] Therefore, an object of the present invention is to realize a composite power inductor for a switching power supply device that can realize desired characteristics with a small number of components and a physically small shape.

[0011] Technical solutions to solve problems

[0012] The switching power supply device with a composite power inductor of the present invention comprises: a first inductor conductor in a straight line shape; a second inductor conductor in a straight line shape; a third inductor conductor; and a magnetic body, forming a magnetic circuit of magnetic flux generated by current flowing through the first inductor conductor, the second inductor conductor, and the third inductor conductor. One end of the first inductor conductor is connected to the first input terminal, and the other end is connected to one end of the third inductor conductor, and one end of the second inductor conductor is connected to the second input terminal, and the other end is connected to one end of the third inductor conductor. The first inductor conductor, the second inductor conductor, and the third inductor conductor are sandwiched by the magnetic body or included inside the magnetic body. The first inductor conductor and the second inductor conductor are arranged in parallel so that: in the inner leg portion between the first inductor conductor and the second inductor conductor in the magnetic body, the magnetic fluxes generated by the current flowing through each conductor cancel each other, and in the outer leg portion of the magnetic body that is closer to the outside than the first inductor conductor and the second inductor conductor, the magnetic fluxes generated by the current flowing through each conductor reinforce each other. The third inductor conductor is arranged so that the plane formed by the magnetic flux generated by the current flowing through the conductor is orthogonal to the plane formed by the magnetic flux generated by the current flowing through the first inductor conductor and the second inductor conductor. The first inductor conductor and the second inductor conductor are inductors constituting a power conversion circuit, and the third inductor conductor is an inductor constituting a low-pass filter for the output current of the power conversion circuit.

[0013] Effects of the Invention

[0014] According to the present invention, the functions realized by multiple power inductors can be constituted by an integrated composite power inductor, and the magnetic saturation of the magnetic body can be suppressed by canceling the magnetic flux generated by the DC output current, and the output voltage ripple can be reduced by forming a low-pass filter for the output current. A composite power inductor for a switching power supply device can be realized with a small number of components and a physically small shape, and as a power inductor and a switching power supply device, desired characteristics such as small size and light weight, high efficiency, and high performance can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an equivalent circuit diagram of a switching power supply device including a composite power inductor according to a first embodiment of the present invention.

[0016] Figure 2 (A) Figure 2 (B) is an external perspective view of the composite power inductor according to the first embodiment of the present invention.

[0017] Figure 3 It is an exploded perspective view of the composite power inductor according to the first embodiment of the present invention.

[0018] Figure 4 These are four views of the composite power inductor according to the first embodiment of the present invention.

[0019] Figure 5 These are four views (a top view, a first end view, a second end view, and a first side view) of a magnetic body in which a first magnetic body and a second magnetic body according to a first embodiment of the present invention are combined, and a top view of the first magnetic body.

[0020] Figure 6 These are four views (a plan view, a first end view, a second end view, and a first side view) of the third magnetic body according to the first embodiment of the present invention.

[0021] Figure 7 These are four views (a plan view, a first end view, a second end view, and a first side view) of the conductor member according to the first embodiment of the present invention.

[0022] Figure 8 (A) Figure 8 (B) Figure 8 (C) is a diagram schematically showing one state of the current and magnetic field of the composite power inductor according to the first embodiment of the present invention.

[0023] Fig. 9 It is a perspective view showing an example of a switching power supply device according to the first embodiment of the present invention.

[0024] Fig.10 It is an exploded perspective view of a composite power inductor according to a second embodiment of the present invention.

[0025] Fig.11 It is a perspective view of the appearance of a composite power inductor according to a second embodiment of the present invention.

[0026] Fig.12 It is a perspective view of the appearance of a composite power inductor according to a third embodiment of the present invention.

[0027] Fig.13 It is an exploded perspective view of a composite power inductor according to a fourth embodiment of the present invention.

[0028] Fig.14 It is an external perspective view of a composite power inductor according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0029] [First embodiment]

[0030] A composite power inductor and a switching power supply device according to a first embodiment of the present invention will be described with reference to the drawings.

[0031] (Circuit structure of a switching power supply device equipped with a composite power inductor)

[0032] Figure 1 FIG. 1 is an equivalent circuit diagram of a switching power supply device having a composite power inductor according to a first embodiment of the present invention. Figure 1 As shown, the switching power supply device 80 includes a composite power inductor 10 , a power semiconductor IC 81 , a power semiconductor IC 82 , a capacitor 881 , a capacitor 882 , and a capacitor 883 .

[0033] The power semiconductor IC 81 includes a drive circuit 810, a switch element Q81H, and a switch element Q81L. The power semiconductor IC 82 includes a drive circuit 820, a switch element Q82H, and a switch element Q82L. The switch element Q81H, the switch element Q81L, the switch element Q82H, and the switch element Q82L are power semiconductor elements, such as power MOSFETs.

[0034] The composite power inductor 10 includes an inductor 11, an inductor 12, and an inductor 13. The composite power inductor 10 includes a first input terminal P101, a second input terminal P102, an output terminal P103, a first capacitor terminal P191, and a second capacitor terminal P192.

[0035] A DC power source is connected between the Hi side power input terminal and the Low side power input terminal of the switching power source device 80. The Hi side power input terminal is connected to the positive electrode of the DC power source, and the Low side power input terminal is connected to the negative electrode of the DC power source.

[0036] The drive circuit 810 is connected to the gate terminal of the switching element Q81H and the gate terminal of the switching element Q81L.

[0037] The drain terminal of the switching element Q81H is connected to the Hi-side power input terminal of the switching power supply device 80. The source terminal of the switching element Q81H is connected to the drain terminal of the switching element Q81L. The source terminal of the switching element Q81L is connected to the Low-side power input terminal (terminal connected to the reference potential line) of the switching power supply device 80. The reference potential line connects the Low-side power input terminal (terminal connected to the negative electrode of the DC power supply) of the switching power supply device 80 and the Low-side output terminal (terminal connected to the negative electrode of the load 89) of the switching power supply device 80.

[0038] A node between a source terminal of the switching element Q81H and a drain terminal of the switching element Q81L is connected to one terminal of the inductor 11 via a first input terminal P101 of the composite power inductor 10 .

[0039] The other terminal of the inductor 11 is connected to one terminal of the capacitor 881 via the first capacitor terminal P191 of the composite power inductor 10. The other terminal of the capacitor 881 is connected to a reference potential line.

[0040] The first power conversion circuit is formed by these power semiconductor IC 81 (drive circuit 810, switch element Q81H, switch element Q81L), inductor 11 and capacitor 881. As described above, inductor 11 is an inductor (first inductor) for the first power conversion circuit, and capacitor 881 is an output capacitor for the first power conversion circuit.

[0041] The drive circuit 820 is connected to the gate terminal of the switching element Q82H and the gate terminal of the switching element Q82L.

[0042] The drain terminal of the switching element Q82H is connected to the Hi-side power input terminal of the switching power supply device 80. The source terminal of the switching element Q82H is connected to the drain terminal of the switching element Q82L. The source terminal of the switching element Q82L is connected to the Low-side power input terminal (terminal connected to the reference potential line) of the switching power supply device 80.

[0043] A node between the source terminal of the switching element Q82H and the drain terminal of the switching element Q82L is connected to one terminal of the inductor 12 via the second input terminal P102 of the composite power inductor 10 .

[0044] The other terminal of the inductor 12 is connected to one terminal of the capacitor 882 via the second capacitor terminal P192 of the composite power inductor 10. The other terminal of the capacitor 882 is connected to the reference potential line.

[0045] The second power conversion circuit is formed by these power semiconductor IC 82 (drive circuit 820, switch element Q82H, switch element Q82L), inductor 12 and capacitor 882. As described above, inductor 12 is an inductor (second inductor) for the second power conversion circuit, and capacitor 882 is an output capacitor for the second power conversion circuit.

[0046] The other terminal of inductor 11 and the other terminal of inductor 12 are connected to one terminal of inductor 13. The other terminal of inductor 13 is connected to the Hi-side output terminal (the terminal connected to the positive electrode of load 89) of switching power supply device 80 via output terminal P103 of composite power inductor 10.

[0047] The capacitor 883 is connected between the Hi-side output terminal and the Low-side output terminal.

[0048] Thus, the inductor 13 and the capacitor 883 constitute an output filter circuit of the switching power supply device 80. Specifically, the inductor 13 and the capacitor 883 constitute a low-pass filter for the output current of the power conversion circuit.

[0049] Furthermore, with the above configuration, the switching power supply device 80 includes the first power conversion circuit and the second power conversion circuit connected in parallel, and an output filter circuit connected to a node between an output terminal of the first power conversion circuit and an output terminal of the second power conversion circuit.

[0050] Thus, the switching power supply device 80 can realize a multi-DC-DC converter using switching elements and suppress output ripple noise.

[0051] (Composite Power Inductor)

[0052] Figure 2 (A) Figure 2 (B) is an external perspective view of the composite power inductor according to the first embodiment of the present invention. Figure 3 It is an exploded perspective view of the composite power inductor according to the first embodiment of the present invention. Figure 4 These are four views of the composite power inductor according to the first embodiment of the present invention. Figure 4 A plan view (a view obtained by viewing the surface opposite to the mounting surface), a first end view, a second end view, and a first side view are shown. Figure 5 These are four views (a top view, a first end view, a second end view, and a first side view) of a magnetic body in which a first magnetic body and a second magnetic body according to a first embodiment of the present invention are combined, and a top view of the first magnetic body. Figure 6 These are four views (a plan view, a first end view, a second end view, and a first side view) of the third magnetic body according to the first embodiment of the present invention. Figure 7 It is a four-view drawing (top view, first end view, second end view, first side view) of the conductor component involved in the first embodiment of the present invention. In addition, in each figure, the three orthogonal axes are called X-axis, Y-axis, and Z-axis, but this is the axis name used to make the description easier, for example, it does not limit the direction in which the composite power inductor 10 is arranged on the circuit board, etc.

[0053] like Figure 2 (A) Figure 2 (B) Figure 3 , Figure 4 As shown, the composite power inductor 10 includes a magnetic body 21, a magnetic body 22, a magnetic body 23, and a conductive member 30. The magnetic body 21 corresponds to a first magnetic member, the magnetic body 22 corresponds to a second magnetic member, and the magnetic body 23 corresponds to a third magnetic member.

[0054] (Magnetic body)

[0055] like Figure 5 As shown, the magnetic body 21 and the magnetic body 22 are flat plates.

[0056] The magnetic body 21 has a main plane 2101, a main plane 2102, an end face 20E1, an end face 20E2, a side face 20S1, and a side face 20S2. The main plane 2101 and the main plane 2102 are opposite to each other and are perpendicular to the Z-axis direction (the thickness direction of the magnetic body 21). The end face 20E1 and the end face 20E2 are opposite to each other, parallel to the X-axis direction (the long side direction of the magnetic body 21 in this embodiment) and perpendicular to the Y-axis direction (the short side direction of the magnetic body 21 in this embodiment). In addition, the end face 20E1 and the end face 20E2 also correspond to the end face of the magnetic body 20 in which the magnetic body 21 and the magnetic body 22 are overlapped. The side face 20S1 and the side face 20S2 are opposite to each other, parallel to the Y-axis direction and perpendicular to the X-axis direction. In addition, the side face 20S1 and the side face 20S2 also correspond to the end face of the magnetic body 20 in which the magnetic body 21 and the magnetic body 22 are overlapped.

[0057] The magnetic body 21 has a groove 211 and a groove 212. The groove 211 and the groove 212 are recessed from the main plane 2101. The groove 211 and the groove 212 are extended parallel to the Y-axis direction of the magnetic body 21, reach the end surface 20E1 and the end surface 20E2, and open to the outside of the magnetic body 21. In the X-axis direction, the distance between the groove 211 and the groove 212 (the inner leg portion 10ZI of the composite power inductor 10 (refer to Figure 2 The width of (A)) is greater than the distance between the groove 211 and the side surface 20S1 (the outer leg portion 10ZO1 of the composite power inductor 10 (refer to Figure 2 (A)) width) and the distance between the groove 212 and the side 20S2 (the outer leg portion 10ZO2 of the composite power inductor 10 (refer to Figure 2 (A)) width) length.

[0058] The grooves 211 and 212 are arranged at intervals in the X-axis direction of the magnetic body 21 . The depths of the grooves 211 and 212 are substantially the same as the heights (thicknesses) of the inductor conductors 31 and 32 of the conductor member 30 .

[0059] The magnetic body 21 includes a groove 213. The groove 213 is shaped to extend in the X-axis direction and communicates with the end of the groove 211 on the end surface 20E2 side and the end of the groove 212. The groove 213 opens to the outside of the magnetic body 21 at the end surface 20E2 of the magnetic body 21.

[0060] The magnetic body 22 contacts the principal plane 2101 of the magnetic body 21. Thus, the magnetic body 20 having a substantially rectangular parallelepiped shape in which the magnetic body 21 and the magnetic body 22 are stacked is formed.

[0061] like Figure 6 As shown, the magnetic body 23 includes a main body 231, a protrusion 232 and a protrusion 233. The main body 231 is a rectangular parallelepiped extending in the X-axis direction. The protrusion 232 is formed at one end in the direction in which the main body 231 extends, and is a shape that protrudes from the main body 231 in the Y-axis direction. The protrusion 233 is formed at the other end in the direction in which the main body 231 extends, and is a shape that protrudes from the main body 231 in the Y-axis direction (the same direction as the protrusion 232).

[0062] The magnetic body 23 is arranged and fixed to the magnetic body 21 so that the tip end surface of the protrusion 232 and the tip end surface of the protrusion 233 abut against the end surface 20E2 of the magnetic body 21 .

[0063] (Conductor component)

[0064] like Figure 7 As shown in FIG. 1 , the conductor member 30 includes an inductor conductor 31, an inductor conductor 32, an inductor conductor 33, a connection conductor 34, a terminal conductor 381, a terminal conductor 382, ​​a terminal conductor 391, and a terminal conductor 392. For example, the inductor conductor 31, the inductor conductor 32, the inductor conductor 33, the connection conductor 34, the terminal conductor 381, the terminal conductor 382, ​​the terminal conductor 391, and the terminal conductor 392 are formed by pressing a conductor plate having a predetermined thickness. In addition, the same in this embodiment means the same within the range including the manufacturing error.

[0065] The inductor conductor 31 and the inductor conductor 32 are plate-shaped and linear conductors. The width W31 of the inductor conductor 31 and the width W32 of the inductor conductor 32 are the same. The width W31 of the inductor conductor 31 and the width W32 of the inductor conductor 32 are the same as the width of the groove 211 and the width of the groove 212 in the magnetic body 21.

[0066] The length of the inductor conductor 31 is the same as the length of the inductor conductor 32 , and the distances between the end surface 20E1 and the end surface 20E2 of the magnetic body 21 are the same.

[0067] The inductor conductor 31 and the inductor conductor 32 are shaped to extend in the Y-axis direction and are arranged at intervals in the X-axis direction. That is, the inductor conductor 31 and the inductor conductor 32 are parallel. The arrangement interval of the inductor conductor 31 and the inductor conductor 32 is the same as the arrangement interval of the grooves 211 and the grooves 212 in the magnetic body 21.

[0068] The terminal conductor 381 is a plate-shaped conductor extending in the Z-axis direction. The terminal conductor 381 is connected to one end of the inductor conductor 31 in the extending direction. The terminal conductor 382 is a plate-shaped conductor extending in the Z-axis direction. The terminal conductor 382 is connected to one end of the inductor conductor 32 in the extending direction.

[0069] The connection conductor 34 is a conductor extending in the X-axis direction and connects the other end of the inductor conductor 31 and the other end of the inductor conductor 32 .

[0070] The inductor conductor 33 is a plate-shaped conductor extending in the Z-axis direction. That is, the direction in which the inductor conductor 33 extends is orthogonal to the direction in which the inductor conductor 31 and the inductor conductor 32 extend.

[0071] The inductor conductor 33 is disposed between the inductor conductor 31 and the inductor conductor 32 in the X-axis direction. The inductor conductor 33 is disposed in the Y-axis direction at substantially the same position as the other end of the direction in which the inductor conductor 31 and the inductor conductor 32 extend. The inductor conductor 33 is disposed in the Z-axis direction on the same side as the terminal conductor 381 and the terminal conductor 382 with respect to the inductor conductor 31 and the inductor conductor 32.

[0072] The inductor conductor 33 is connected to the other end of the inductor conductor 31 and the other end of the inductor conductor 32 via the connection conductor 34 .

[0073] The width W33 of the inductor conductor 33 is larger than the width W31 of the inductor conductor 31 and the width of the inductor conductor 32 ( W33 > W31 = W32 ).

[0074] The terminal conductor 391 is a plate-shaped conductor extending in the Z-axis direction. The terminal conductor 391 is connected to the other end in the direction in which the inductor conductor 31 extends. The terminal conductor 392 is a plate-shaped conductor extending in the Z-axis direction. The terminal conductor 392 is connected to one end in the direction in which the inductor conductor 32 extends. The terminal conductors 391 and 392 are arranged on the same side as the inductor conductor 33, the terminal conductors 381, and the terminal conductors 382 with respect to the inductor conductors 31 and 32 in the Z-axis direction.

[0075] (Specific structure of composite power inductor)

[0076] like Figure 2 (A) Figure 2 (B) Figure 3As shown, the conductor member 30 is arranged on the magnetic body 21 so that the inductor conductor 31 and the inductor conductor 32 are respectively embedded in the groove 211 and the groove 212 of the magnetic body 21. The connection conductor 34 of the conductor member 30 is arranged so that at least a portion is embedded along the groove 213 of the magnetic body 21. The inductor conductor 33, the terminal conductor 391 and the terminal conductor 392 of the conductor member 30 are in contact with the end surface 20E2 of the magnetic body 21. The terminal conductor 381 and the terminal conductor 382 of the conductor member 30 are in contact with the end surface 20E1 of the magnetic body 21. In addition, the terminal conductor 391 and the terminal conductor 392 may not be in contact with the end surface 20E2. Similarly, the terminal conductor 381 and the terminal conductor 382 may not be in contact with the end surface 20E1.

[0077] The tip of the terminal conductor 381 (the tip opposite to the end connected to the inductor conductor 31 ) and the tip of the terminal conductor 382 (the tip opposite to the end connected to the inductor conductor 32 ) are substantially flush with the principal plane 2102 of the magnetic body 21 .

[0078] The tip end of the terminal conductor 391 (the end opposite to the end connected to the inductor conductor 31 ) and the tip end of the terminal conductor 392 (the end opposite to the end connected to the inductor conductor 32 ) are substantially flush with the principal plane 2102 of the magnetic body 21 .

[0079] The tip end of the inductor conductor 33 (the end on the opposite side to the end connected to the inductor conductor 31 and the inductor conductor 32 via the connection conductor 34 ) is substantially flush with the principal plane 2102 of the magnetic body 21 .

[0080] The magnetic body 23 is arranged to surround the inductor conductor 33. Specifically, the magnetic body 23 is fixed to the end surface 20E1 of the magnetic body 21 so that the inductor conductor 33 is embedded between the protrusion 232 and the protrusion 233.

[0081] With such a structure, the inductor conductor 31 and the inductor conductor 32 are surrounded by the laminated body of the magnetic body 21 and the magnetic body 22. The inductor conductor 31 is sandwiched between the inner leg portion 10ZI and the outer leg portion 10ZO1. The inductor conductor 32 is sandwiched between the inner leg portion 10ZI and the outer leg portion 10ZO2.

[0082] Furthermore, the inductor conductor 33 is surrounded by the magnetic body 21 and the magnetic body 23 .

[0083] (Connection Relationship Between Composite Power Inductor 10 and Other Circuit Elements of Switching Power Supply Device 80)

[0084] The top end of the terminal conductor 381 is connected to the node of the switch element Q81H and the switch element Q81L of the power semiconductor IC 81. The terminal conductor 381 is the first input terminal P101 of the composite power inductor 10 in the equivalent circuit. The inductor conductor 31 is the inductor 11 of the composite power inductor 10 in the equivalent circuit, and corresponds to the first inductor conductor of the present invention.

[0085] The top end of the terminal conductor 382 is connected to the node of the switch element Q82H and the switch element Q82L of the power semiconductor IC 82. The top end of the terminal conductor 382 is the second input terminal P102 of the composite power inductor 10 in the equivalent circuit. The inductor conductor 32 is the inductor 12 of the composite power inductor 10 in the equivalent circuit, and corresponds to the second inductor conductor of the present invention.

[0086] The tip of the inductor conductor 33 is connected to the Hi-side output terminal of the switching power supply device 80 and one terminal of the capacitor 883. The tip of the inductor conductor 33 is the output terminal P103 of the composite power inductor 10 in the equivalent circuit. The inductor conductor 33 is the inductor 13 of the composite power inductor 10 in the equivalent circuit, and corresponds to the third inductor conductor of the present invention.

[0087] The tip of the terminal conductor 391 is connected to one terminal of the capacitor 881. The tip of the terminal conductor 391 is the first capacitor terminal P191 of the composite power inductor 10 in the equivalent circuit, and the terminal conductor 391 corresponds to the first capacitor terminal conductor of the present invention.

[0088] The tip of the terminal conductor 392 is connected to one terminal of the capacitor 882. The tip of the terminal conductor 392 is the second capacitor terminal P192 of the composite power inductor 10 in the equivalent circuit, and the terminal conductor 392 corresponds to the second capacitor terminal conductor of the present invention.

[0089] (Current and magnetic field of composite power inductor)

[0090] Figure 8 (A) Figure 8 (B) Figure 8 (C) is a diagram schematically showing one state of the current and magnetic field of the composite power inductor according to the first embodiment of the present invention. Figure 8 (A) is a stereogram, Figure 8 (B) is a top view. Figure 8 (C) is an end view.

[0091] like Figure 8 (A) Figure 8 (B) Figure 8As shown in (C), when the switching power supply device 80 operates, currents flow in the same direction in the inductor conductor 31 and the inductor conductor 32. Specifically, in the inductor conductor 31, the current I31 flows from the end surface 20E2 toward the end surface 20E1, and in the inductor conductor 32, the current I32 flows from the end surface 20E2 toward the end surface 20E1, and the directions of the currents I31 and I32 are the same.

[0092] Thus, in the inner leg portion 10ZI between the inductor conductor 31 and the inductor conductor 32, the direction of the magnetic field H31 generated by the current I31 passing through the inductor conductor 31 and the direction of the magnetic field H32 generated by the current I32 passing through the inductor conductor 32 become opposite. Thus, the magnetic flux based on the current I31 of the inductor conductor 31 and the magnetic flux based on the current I32 of the inductor conductor 32 cancel each other out. Therefore, the magnetic flux density in the inner leg portion 10ZI can be reduced, and magnetic saturation can be suppressed. As a result, the distance between the inductor conductor 31 and the inductor conductor 32 can be shortened, in other words, the width of the inner leg portion 10ZI can be narrowed. Therefore, the composite power inductor 10 can suppress characteristic degradation and achieve miniaturization.

[0093] In addition, the directions of the magnetic field H31 and the magnetic field H32 in the outer leg 10ZO1 are the same, and the directions of the magnetic field H31 and the magnetic field H32 in the outer leg 10ZO2 are the same. As a result, in the outer leg 10ZO1 and the outer leg 10ZO2, the magnetic flux based on the current I31 of the inductor conductor 31 and the magnetic flux based on the current I32 of the inductor conductor 32 reinforce each other. Therefore, the composite power inductor 10 can improve the characteristics without increasing the size.

[0094] In addition, if Figure 8 (A) Figure 8 (B) Figure 8 As shown in (C), when the switching power supply device 80 is in operation, a current I33 flows in the inductor conductor 33 in parallel with the stacking direction of the magnetic body 21 and the magnetic body 22. That is, the direction of the current I33 flowing in the inductor conductor 33 is orthogonal to the direction of the current I31 flowing in the inductor conductor 31 and the direction of the current I32 flowing in the inductor conductor 32.

[0095] Thus, the plane formed by the magnetic field H33 based on the current I33 is orthogonal to the plane formed by the magnetic field H31 based on the current I31 and the plane formed by the magnetic field H32 based on the current I32. Therefore, the magnetic flux based on the current I33 is not substantially coupled with the magnetic flux based on the current I31 and the magnetic flux based on the current I32, and the magnetic flux density does not increase. As a result, the magnetic saturation of the inductor conductor 33 can be suppressed, and the output filter circuit including the inductor conductor 33 (inductor 13) can achieve the desired filter characteristics without increasing the shape of the composite power inductor 10.

[0096] As described above, according to the structure of the present embodiment, the composite power inductor 10 can be realized in a physically small shape, and desired characteristics can be realized as the composite power inductor 10 and the switching power supply device 80. In addition, the composite power inductor 10 realizes the inductors of multiple power conversion circuits and the inductors of the output filter circuit in one housing, and the number of components can be reduced compared to the previous structure in which the inductors of multiple power conversion circuits and the inductors of the output filter circuit are separately provided. That is, the functions realized by multiple power inductors can be constituted by one integrated composite power inductor, and the magnetic saturation of the magnetic body can be suppressed by offsetting the magnetic flux generated by the DC output current, and the output voltage ripple can be reduced by constituting a low-pass filter for the output current.

[0097] Furthermore, in the structure of the present embodiment, the inductor conductor 31 and the inductor conductor 32 are surrounded by the laminate of the magnetic body 21 and the magnetic body 22. Thus, the inductance of the inductor 11 based on the inductor conductor 31 and the inductance of the inductor 12 based on the inductor conductor 32 can be increased without changing the shape. In addition, the magnetic flux of the current I31 based on the inductor conductor 31 and the magnetic flux based on the inductor conductor 32 are concentrated inside the laminate of the magnetic body 21 and the magnetic body 22, and are not easily leaked to the outside. Therefore, the composite power inductor 10 can achieve a small shape and suppress the influence on the outside.

[0098] Similarly, the inductor conductor 33 is surrounded by the magnetic body 21 and the magnetic body 23. Thus, the inductance of the inductor 13 based on the inductor conductor 33 can be increased without changing the shape. In addition, the magnetic flux of the current I33 based on the inductor conductor 33 is concentrated inside the structure including the magnetic body 21 and the magnetic body 23, and is not easy to leak to the outside. Therefore, the composite power inductor 10 can achieve a small shape, and the magnetic flux of the inductor conductor 33 is suppressed from coupling to the terminal conductor 391 and the terminal conductor 392, and the influence on the outside can be suppressed.

[0099] Furthermore, in the composite power inductor 10, the width W33 of the inductor conductor 33 is wider than the width W31 of the inductor conductor 31 and the width W32 of the inductor conductor 32. The current I33 of the inductor conductor 33 is a composite current of the current I31 of the inductor conductor 31 and the current I32 of the inductor conductor 32, and is larger than the current I31 and the current I32.

[0100] However, since the width W33 of the inductor conductor 33 is large, even if the current I33 increases, the resistance to the current I33 can be reduced, and the composite power inductor 10 can suppress the transmission loss and heat loss in the inductor conductor 33 .

[0101] In addition, the length of the inductor conductor 33 is shorter than the length of the inductor conductor 31 and the length of the inductor conductor 32. Therefore, even if the current I33 increases, the resistance to the current I33 can be reduced, and the composite power inductor 10 can suppress the transmission loss and heat loss in the inductor conductor 33.

[0102] (Structural example of a switching power supply device)

[0103] Fig. 9 1 is a perspective view showing an example of a switching power supply device according to a first embodiment of the present invention. Fig. 9 As shown, the switching power supply device 80 includes a circuit board 800, a composite power inductor 10, a power semiconductor IC 81, a power semiconductor IC 82, a plurality of capacitors 881, a plurality of capacitors 882, and a plurality of capacitors 883. The composite power inductor 10, the power semiconductor IC 81, the power semiconductor IC 82, the plurality of capacitors 881, the plurality of capacitors 882, and the plurality of capacitors 883 are mounted electronic components.

[0104] The circuit board 800 includes a component mounting surface and a grounding surface. On the component mounting surface, a connection conductor pattern 801, a connection conductor pattern 802, a connection conductor pattern 803, a connection conductor pattern 804, and a connection conductor pattern 805 are formed, each in the form of a film. In addition, on the component mounting surface, a plurality of grounding conductor patterns 809 are formed, each in the form of a film. On the grounding surface, a grounding conductor pattern 890 is formed. The grounding conductor pattern 890 is formed at a position that overlaps at least with the plurality of grounding conductor patterns 809 when the circuit board 800 is viewed from above, for example, formed on substantially the entire surface.

[0105] The power semiconductor IC81 and the power semiconductor IC82 are arranged on the end surface 20E2 side of the composite power inductor 10. The power semiconductor IC81 and the power semiconductor IC82 are arranged along the end surface 20E2, the power semiconductor IC81 is arranged at a position close to the terminal conductor 381 of the composite power inductor 10, and the power semiconductor IC82 is arranged at a position close to the terminal conductor 382 of the composite power inductor 10.

[0106] The power semiconductor IC 81 and the terminal conductor 381 are mounted on the connection conductor pattern 801 and are electrically and physically connected to the connection conductor pattern 801. The power semiconductor IC 82 and the terminal conductor 382 are mounted on the connection conductor pattern 802 and are electrically and physically connected to the connection conductor pattern 802.

[0107] Multiple capacitors 881, multiple capacitors 882, and multiple capacitors 883 are arranged on the end surface 20E1 side of the composite power inductor 10. Multiple capacitors 881 are arranged near the terminal conductor 391 of the composite power inductor 10, multiple capacitors 882 are arranged near the terminal conductor 392 of the composite power inductor 10, and multiple capacitors 883 are arranged near the inductor conductor 33 of the composite power inductor 10.

[0108] The inductor conductor 33 and the plurality of capacitors 883 are mounted on the connection conductor pattern 803 and are electrically and physically connected to the connection conductor pattern 803. The terminal conductor 391 and the plurality of capacitors 881 are mounted on the connection conductor pattern 804 and are electrically and physically connected to the connection conductor pattern 804. The terminal conductor 392 and the plurality of capacitors 882 are mounted on the connection conductor pattern 805 and are electrically and physically connected to the connection conductor pattern 805.

[0109] The plurality of capacitors 881 , the plurality of capacitors 882 , and the plurality of capacitors 883 are respectively mounted on the ground conductor pattern 809 , and are electrically connected to a reference potential.

[0110] With such a structure, the switching power supply device 80 can realize a space-saving shape.

[0111] [Second embodiment]

[0112] A composite power inductor according to a second embodiment of the present invention will be described with reference to the drawings. Fig.10 It is an exploded perspective view of a composite power inductor according to a second embodiment of the present invention. Fig.11 It is a perspective view of the appearance of a composite power inductor according to a second embodiment of the present invention.

[0113] like Fig.10 , Fig.11As shown, the composite power inductor 10A according to the second embodiment differs from the composite power inductor 10 according to the first embodiment in the structure of the conductor member 30A and the arrangement of the magnetic body 23. The other structures of the composite power inductor 10A are the same as those of the composite power inductor 10, and the description of the same parts is omitted.

[0114] The conductor member 30A includes an inductor conductor 33A. The inductor conductor 33A is disposed on the opposite side of the terminal conductors 391 and 392 with respect to the inductor conductors 31 and 32 in the Z-axis direction. Thus, the inductor conductor 33A contacts the end surface of the magnetic body 22.

[0115] The magnetic body 23 is fixed to the end surface of the magnetic body 22 so as to surround the inductor conductor 33A.

[0116] With such a configuration, similarly to the composite power inductor 10 according to the first embodiment, the composite power inductor 10A can be realized in a physically small shape and desired characteristics can be realized as the composite power inductor 10A.

[0117] Furthermore, in this structure, the inductor conductor 33A is not sandwiched between the terminal conductor 391 and the terminal conductor 392. Therefore, the width of the inductor conductor 33A can be increased. Thus, the composite power inductor 10A can suppress various losses caused by current.

[0118] Furthermore, in this configuration, the length of the inductor conductor 33A need not be the same as the lengths of the terminal conductors 391 and 392. Thus, the composite power inductor 10A can adjust the inductance of the inductor conductor 33A and can adjust the filter characteristics of the output filter circuit.

[0119] [Third Embodiment]

[0120] A composite power inductor according to a third embodiment of the present invention will be described with reference to the drawings. Fig.12 It is a perspective view of the appearance of a composite power inductor according to a third embodiment of the present invention.

[0121] like Fig.12 As shown, the composite power inductor 10B according to the third embodiment is different from the composite power inductor 10 according to the first embodiment in that the magnetic body 23 is omitted. The other structures of the composite power inductor 10B are the same as those of the composite power inductor 10, and the description of the same parts is omitted.

[0122] The conductor member 30B of the composite power inductor 10B includes an inductor conductor 33B. The inductor conductor 33B abuts against the end surface 20E1 of the magnetic body 21, and is exposed to the outside except for the abutting surface. With such a structure, the inductance of the inductor 13 based on the inductor conductor 33B can be reduced. Thus, the composite power inductor 10B can adjust the filter characteristics of the output filter circuit.

[0123] In addition, in this structure, there is no need to insert a space for a magnetic body between the inductor conductor 33B and the terminal conductor 391. Similarly, in this structure, there is no need to insert a space for a magnetic body between the inductor conductor 33B and the terminal conductor 391. As a result, the width of the inductor conductor 33B can be widened, and the composite power inductor 10B can suppress various losses caused by current.

[0124] [Fourth embodiment]

[0125] A composite power inductor according to a fourth embodiment of the present invention will be described with reference to the drawings. Fig.13 It is an exploded perspective view of a composite power inductor according to a fourth embodiment of the present invention. Fig.14 It is an external perspective view of a composite power inductor according to a fourth embodiment of the present invention.

[0126] like Fig.13 , Fig.14 As shown, the composite power inductor 10C according to the fourth embodiment differs from the composite power inductor 10 according to the first embodiment in the magnetic body 21C, the magnetic body 23C, and the conductor member 30C. The other structures of the composite power inductor 10C are the same as those of the composite power inductor 10, and the description of the same parts is omitted.

[0127] The composite power inductor 10C includes a magnetic body 21C, a magnetic body 23C, and a conductor member 30C.

[0128] The magnetic body 21C is different from the magnetic body 21 involved in the first embodiment in that it has a through hole 214C. The through hole 214C is formed along the groove 213, and the internal space of the through hole 214C is a rectangular parallelepiped shape. The through hole 214C is formed at a position farther from the end face 20E1 than the groove 213 (the position on the end face 20E2 side). The through hole 214C penetrates between the bottom surface of the grooves 213, 211, and 212 and the main plane 2102 of the magnetic body 21C. In other words, the magnetic body 21C is penetrated in the thickness direction (Z-axis direction).

[0129] The conductor member 30C includes an inductor conductor 33C and a connecting conductor 34C. The inductor conductor 33C is arranged at a position offset to one end side from the other end (the end connected to the terminal conductor 391 and the terminal conductor 392, respectively) of the inductor conductor 31 and the inductor conductor 32. The inductor conductor 33C is connected to the inductor conductor 31 and the inductor conductor 32 via the connecting conductor 34C.

[0130] The conductor member 30C is disposed on the magnetic body 21C such that the inductor conductor 31 is embedded in the groove 211 , the inductor conductor 32 is embedded in the groove 212 , and the inductor conductor 33C is inserted into the through hole 214C.

[0131] The magnetic body 23C has a rectangular parallelepiped shape and is embedded in the groove 213 .

[0132] With such a structure, the composite power inductor 10C is provided with the inductor conductor 31, the inductor conductor 32, and the inductor conductor 33C inside the laminate of the magnetic body 21C and the magnetic body 22. Thus, even if the composite power inductor 10C does not have a portion protruding from the laminate of the magnetic body 21 and the magnetic body 22 to the outside like the magnetic body 23 of the composite power inductor 10, the composite power inductor 10C can achieve the same characteristics as the composite power inductor 10. Therefore, the composite power inductor 10C can be smaller than the composite power inductor 10 and have the same function and effect as the composite power inductor 10.

[0133] In addition, the structures of the above-mentioned embodiments can be combined appropriately, and the effects corresponding to the respective combinations can be achieved.

[0134] <1> A switching power supply device with a composite power inductor, comprising:

[0135] A first inductor conductor having a straight shape;

[0136] A second inductor conductor having a straight shape;

[0137] a third inductor conductor; and

[0138] a magnetic body that forms a magnetic path of magnetic flux generated by current flowing through the first inductor conductor, the second inductor conductor, and the third inductor conductor,

[0139] One end of the first inductor conductor is connected to the first input terminal, and the other end is connected to one end of the third inductor conductor.

[0140] One end of the second inductor conductor is connected to the second input terminal, and the other end is connected to one end of the third inductor conductor.

[0141] The first inductor conductor, the second inductor conductor, and the third inductor conductor are sandwiched by the magnetic body or included inside the magnetic body.

[0142] The first inductor conductor and the second inductor conductor are arranged in parallel such that:

[0143] In the inner leg portion between the first inductor conductor and the second inductor conductor in the magnetic body, magnetic fluxes generated by currents flowing through the respective conductors cancel each other out, and

[0144] In the outer leg portion of the magnetic body located outside the first inductor conductor and the second inductor conductor, magnetic fluxes generated by currents flowing through the conductors are mutually reinforced.

[0145] The third inductor conductor is arranged so that a plane formed by a magnetic flux generated by a current flowing through the conductor and a plane formed by a magnetic flux generated by a current flowing through the first inductor conductor and the second inductor conductor are orthogonal to each other.

[0146] The first inductor conductor and the second inductor conductor are inductors constituting a power conversion circuit.

[0147] The third inductor conductor is an inductor that forms a low-pass filter for an output current of the power conversion circuit.

[0148] <2> exist <1> In the switching power supply device having a composite power inductor,

[0149] The magnetic body includes a first magnetic member and a second magnetic member, wherein the first magnetic member and the second magnetic member have portions overlapping each other.

[0150] A portion of the first inductor conductor and a portion of the second inductor conductor are sandwiched between the first magnetic member and the second magnetic member, or are included inside the first magnetic member and the second magnetic member.

[0151] <3> exist <1> or <2> In the switching power supply device having a composite power inductor,

[0152] The first magnetic member has a through hole,

[0153] At least a portion of the third inductor conductor passes through the through hole.

[0154] <4> exist <1> or <2> In the switching power supply device having a composite power inductor,

[0155] The magnetic body includes a third magnetic member having a portion overlapping with at least one of the first magnetic member and the second magnetic member.

[0156] At least a portion of the third inductor conductor is surrounded by the first magnetic member or the second magnetic member and the third magnetic member.

[0157] <5> exist <1> to <4> In any one of the switching power supply devices having a composite power inductor,

[0158] The first inductor conductor and the second inductor conductor are longer than the third inductor conductor.

[0159] <6> exist <1> to <5> In any one of the switching power supply devices having a composite power inductor,

[0160] At least a portion of the third inductor conductor is wider than the first inductor conductor and the second inductor conductor.

[0161] <7> exist <1> to <6> In any one of the switching power supply devices having a composite power inductor,

[0162] The switching power supply device having a composite power inductor comprises:

[0163] a first capacitor terminal conductor connected to the other end of the first inductor conductor and one end of the third inductor conductor; and

[0164] The second capacitor terminal conductor is connected to the other end of the second inductor conductor and one end of the third inductor conductor.

[0165] <8> exist <7> In the switching power supply device having a composite power inductor,

[0166] The magnetic body has:

[0167] principal planes; and

[0168] The first end face and the second end face are perpendicular to the main plane and face each other.

[0169] The first inductor conductor and the second inductor conductor are arranged along the main plane.

[0170] The third inductor conductor, the first capacitor terminal conductor, and the second capacitor terminal conductor are arranged along the first end surface.

[0171] <9> exist <8> In the switching power supply device having a composite power inductor,

[0172] The switching power supply device having a composite power inductor comprises:

[0173] a circuit board on which the composite power inductor is mounted and which has a grounding conductor pattern; and

[0174] The first capacitor element, the second capacitor element, and the third capacitor element are mounted on the circuit substrate.

[0175] The first capacitor element is connected between the first capacitor terminal conductor and the ground conductor pattern.

[0176] The second capacitor element is connected between the second capacitor terminal conductor and the ground conductor pattern.

[0177] The third capacitor element is connected between the other end of the third inductor conductor and the ground conductor pattern.

[0178] <10> exist <1> to <9> In any one of the switching power supply devices having a composite power inductor,

[0179] The switching power supply device having a composite power inductor comprises:

[0180] a first power conversion circuit including a first inductor using the first inductor conductor;

[0181] a second power conversion circuit including a second inductor using the second inductor conductor; and

[0182] The output filter circuit includes a third inductor using the third inductor conductor.

[0183] Description of Reference Numerals

[0184] Q81H, Q81L, Q82H, Q82L: Switching elements

[0185] 10, 10A, 10B, 10C: Composite power inductors

[0186] 10ZI: Inner Leg

[0187] 10ZO1, 10ZO2: Outer leg

[0188] 11, 12, 13: Inductor

[0189] 20, 21, 21C, 22, 23, 23C: Magnetic

[0190] 20E1, 20E2: End face

[0191] 20S1, 20S2: Side

[0192] 30, 30A, 30B, 30C: Conductor components

[0193] 31, 32, 33, 33A, 33B, 33C: Inductor conductors

[0194] 34, 34C: Connecting conductor

[0195] 80: Switching power supply device

[0196] 81, 82: Power semiconductor IC

[0197] 89: Load

[0198] 211, 212, 213: Grooves

[0199] 214C: Through hole

[0200] 231: Main body

[0201] 232, 233: protrusion

[0202] 381, 382, ​​391, 392: Terminal conductor

[0203] 800: Circuit board

[0204] 801, 802, 803, 804, 805: Connecting conductor pattern

[0205] 809: Grounding conductor pattern

[0206] 810, 820: driving circuit

[0207] 881, 882, 883: Capacitors

[0208] 890: Grounding conductor pattern

[0209] 2101, 2102: Main plane

[0210] P101: 1st input terminal

[0211] P102: Second input terminal

[0212] P103: Output terminal

[0213] P191: Terminal for the first capacitor

[0214] P192: Terminal for the second capacitor.

Claims

1. A switching power supply device having a composite power inductor, comprising: a first inductor conductor having a straight shape; a second inductor conductor having a straight shape; a third inductor conductor; and a magnetic body that forms a magnetic path of magnetic flux generated by current flowing through the first inductor conductor, the second inductor conductor, and the third inductor conductor; One end of the first inductor conductor is connected to the first input terminal, and the other end is connected to one end of the third inductor conductor. One end of the second inductor conductor is connected to the second input terminal, and the other end is connected to one end of the third inductor conductor. The first inductor conductor, the second inductor conductor, and the third inductor conductor are sandwiched by the magnetic body or included inside the magnetic body. The first inductor conductor and the second inductor conductor are arranged in parallel such that: In the inner leg portion between the first inductor conductor and the second inductor conductor in the magnetic body, magnetic fluxes generated by currents flowing through the respective conductors cancel each other out, and In the outer leg portion of the magnetic body located outside the first inductor conductor and the second inductor conductor, magnetic fluxes generated by currents flowing through the respective conductors are mutually reinforced. The third inductor conductor is arranged so that a plane formed by a magnetic flux generated by a current flowing through the conductor and a plane formed by magnetic flux generated by a current flowing through the first inductor conductor and the second inductor conductor are orthogonal to each other. The first inductor conductor and the second inductor conductor are inductors constituting a power conversion circuit. The third inductor conductor is an inductor that forms a low-pass filter for the output current of the power conversion circuit.

2. The switching power supply device having a composite power inductor according to claim 1, wherein: The magnetic body includes a first magnetic member and a second magnetic member, wherein the first magnetic member and the second magnetic member have portions that overlap with each other. A portion of the first inductor conductor and a portion of the second inductor conductor are sandwiched between the first magnetic member and the second magnetic member, or are included inside the first magnetic member and the second magnetic member.

3. The switching power supply device including the composite power inductor according to claim 1 or 2, wherein: The first magnetic member has a through hole, At least a portion of the third inductor conductor passes through the through-hole.

4. The switching power supply device including the composite power inductor according to claim 1 or 2, wherein: The magnetic body includes a third magnetic member having a portion overlapping with at least one of the first magnetic member and the second magnetic member. At least a portion of the third inductor conductor is surrounded by the first magnetic member or the second magnetic member and the third magnetic member.

5. The switching power supply device including the composite power inductor according to any one of claims 1 to 4, wherein: The first inductor conductor and the second inductor conductor are longer than the third inductor conductor.

6. The switching power supply device including the composite power inductor according to any one of claims 1 to 5, wherein: At least a portion of the third inductor conductor is wider than the first inductor conductor and the second inductor conductor.

7. The switching power supply device including the composite power inductor according to any one of claims 1 to 6, wherein: The switching power supply device including the composite power inductor includes: a first capacitor terminal conductor connected to the other end of the first inductor conductor and one end of the third inductor conductor; and The second capacitor terminal conductor is connected to the other end of the second inductor conductor and one end of the third inductor conductor.

8. The switching power supply device including the composite power inductor according to claim 7, wherein: The magnetic body has: principal planes; and The first end face and the second end face are perpendicular to the main plane and face each other. The first inductor conductor and the second inductor conductor are arranged along the main plane. The third inductor conductor, the first capacitor terminal conductor, and the second capacitor terminal conductor are arranged along the first end face.

9. The switching power supply device including the composite power inductor according to claim 8, wherein: The switching power supply device including the composite power inductor includes: a circuit board on which the composite power inductor is mounted and which has a grounding conductor pattern; and The first capacitor element, the second capacitor element, and the third capacitor element are mounted on the circuit substrate. The first capacitor element is connected between the first capacitor terminal conductor and the ground conductor pattern. The second capacitor element is connected between the second capacitor terminal conductor and the ground conductor pattern. The third capacitor element is connected between the other end of the third inductor conductor and the ground conductor pattern.

10. The switching power supply device including the composite power inductor according to any one of claims 1 to 9, wherein: The switching power supply device including the composite power inductor includes: a first power conversion circuit including a first inductor using the first inductor conductor; a second power conversion circuit including a second inductor using the second inductor conductor; and The output filter circuit includes a third inductor using the third inductor conductor.

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