Switching power source device equipped with composite power inductor

Abstract

Provided is a switching power source device (80) equipped with a composite power inductor (10), the switching power source device comprising: a linear inductor conductor (31); a linear inductor conductor (32); an inductor conductor (33); and one magnetic body (20) that forms a magnetic path of a magnetic flux generated by a current flowing to the inductor conductor (31), the inductor conductor (32), and the inductor conductor (33). One end of the inductor conductor (31) is connected to a first input terminal, and the other end is connected to one end of the inductor conductor (33). One end of the inductor conductor (32) is connected to a 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 or contained in the magnetic body (20). The inductor conductor (31) and the inductor conductor (32) are arranged in parallel so that the magnetic fluxes generated by the current flowing to each conductor are cancelled out at an inner leg section (10ZI) of the magnetic body (20) between the inductor conductor (31) and the inductor conductor (32), and the magnetic fluxes generated by the current flowing to each conductor are intensified at outer leg sections (10ZO1, 10ZO2) of the magnetic body (20) on the outside of the inductor conductor (31) and the inductor conductor (32). The inductor conductor (33) is arranged so that a plane created by the magnetic flux generated by the current flowing to the inductor conductor (33) is orthogonal to the planes created by the magnetic fluxes generated by the current flowing to the inductor conductor (31) and the inductor conductor (32). The inductor conductor (31) and the inductor conductor (32) are inductors that constitute a power conversion circuit, and the inductor conductor (33) is an inductor that constitutes a low-pass filter with respect to an output current of the power conversion circuit.

Description

Switching power supply with composite power inductor

[0001] The present invention relates to a switching power supply device equipped with a composite power inductor.

[0002] Patent Document 1 describes 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] JP 2007-194474 A

[0005] However, in the configuration described in Patent Document 1, if it is necessary to connect an inductor to the center tap in a circuit, the ferrite laminate component must include a separate inductor element.

[0006] For example, to suppress output ripple noise in a switching power supply device equipped with multiple power conversion circuits, it is necessary to provide a filter circuit at the output terminals of the multiple power conversion circuits. However, if this is to be achieved using the configuration of Patent Document 1, the inductors of the multiple power conversion circuits and the inductor of the filter circuit (output filter circuit) must be installed separately. This increases the number of components that make up the switching power supply device, making it physically larger.

[0007] Therefore, an object of the present invention is to provide a composite power inductor for a switching power supply that can achieve desired characteristics with a small number of parts and a physically small shape.

[0008] A switching power supply device equipped with a composite power inductor of the present invention includes a linear first inductor conductor, a linear second inductor conductor, a third inductor conductor, and a magnetic body that forms a magnetic path for 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 a first input terminal, the other end is connected to one end of the third inductor conductor, and one end of the second inductor conductor is connected to a 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 within or enclosed by the magnetic body. The first inductor conductor and the second inductor conductor are arranged parallel to each other so that, in an inner leg of the magnetic body between the first inductor conductor and the second inductor conductor, magnetic flux generated by current flowing through each conductor cancels out, and, in outer legs of the magnetic body outside the first inductor conductor and the second inductor conductor, magnetic flux generated by current flowing through each conductor reinforces. The third inductor conductor is arranged so that a plane formed by a magnetic flux generated by a current flowing through the third inductor conductor is perpendicular to a plane formed by a magnetic flux generated by a current flowing through the first inductor conductor and the second inductor conductor. The first inductor conductor and the second inductor conductor are inductors that constitute a power conversion circuit, and the third inductor conductor is an inductor that constitutes a low-pass filter for the output current of the power conversion circuit.

[0009] According to this invention, the functions realized by multiple power inductors can be configured into a single integrated composite power inductor, magnetic saturation of the magnetic material can be suppressed by canceling out the magnetic flux generated by the DC output current, and 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 can be realized with a small number of parts and a physically small shape, and the desired characteristics of the power inductor and switching power supply can be achieved, such as small size and weight, high efficiency, and high performance.

[0010] FIG. 1 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. FIGS. 2A and 2B are external perspective views of the composite power inductor according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of the composite power inductor according to the first embodiment of the present invention. FIG. 4 is a four-sided view of the composite power inductor according to the first embodiment of the present invention. FIG. 5 is a four-sided view (plan view, first end view, second end view, first side view) of a magnetic body combining a first magnetic body and a second magnetic body according to the first embodiment of the present invention, and a plan view of the first magnetic body. FIG. 6 is a four-sided view (plan view, first end view, second end view, first side view) of a third magnetic body according to the first embodiment of the present invention. FIG. 7 is a four-sided view (plan view, first end view, second end view, first side view) of a conductor member according to the first embodiment of the present invention. FIGS. 8A, 8B, and 8C are simplified diagrams showing one state of a current and a magnetic field in the composite power inductor according to the first embodiment of the present invention. Fig. 9 is a perspective view showing an example of a switching power supply device according to a first embodiment of the present invention. Fig. 10 is an exploded perspective view of a composite power inductor according to a second embodiment of the present invention. Fig. 11 is an external perspective view of a composite power inductor according to the second embodiment of the present invention. Fig. 12 is an external perspective view of a composite power inductor according to a third embodiment of the present invention. Fig. 13 is an exploded perspective view of a composite power inductor according to a fourth embodiment of the present invention. Fig. 14 is an external perspective view of a composite power inductor according to the fourth embodiment of the present invention.

[0011] First Embodiment 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.

[0012] (Circuit Configuration of Switching Power Supply Device Equipped with Composite Power Inductor) Fig. 1 is an equivalent circuit diagram of a switching power supply device equipped with a composite power inductor according to a first embodiment of the present invention. As shown in Fig. 1, a 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.

[0013] The power semiconductor IC 81 includes a driver circuit 810, a switching element Q81H, and a switching element Q81L. The power semiconductor IC 82 includes a driver circuit 820, a switching element Q82H, and a switching element Q82L. The switching elements Q81H, Q81L, Q82H, and Q82L are power semiconductor elements, such as power MOSFETs.

[0014] 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.

[0015] 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 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.

[0016] Driver circuit 810 is connected to the gate terminal of switching element Q81H and the gate terminal of switching element Q81L.

[0017] The drain terminal of switching element Q81H is connected to the high-side power supply input terminal of switching power supply 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 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 80 and the low-side output terminal of switching power supply 80 (terminal connected to the negative pole of load 89).

[0018] The node between the source terminal of switching element Q81H and the drain terminal of switching element Q81L is connected to one terminal of inductor 11 through first input terminal P101 of composite power inductor 10.

[0019] The other terminal of the inductor 11 is connected to one terminal of the capacitor 881 through the first capacitor terminal P191 of the composite power inductor 10. The other terminal of the capacitor 881 is connected to the reference potential line.

[0020] A first power conversion circuit is configured by the power semiconductor IC 81 (driver circuit 810, switching element Q81H, switching element Q81L), inductor 11, and capacitor 881. In this way, 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.

[0021] Driver circuit 820 is connected to the gate terminal of switching element Q82H and the gate terminal of switching element Q82L.

[0022] The drain terminal of switching element Q82H is connected to the high-side power supply input terminal of switching power supply device 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 device 80 (the terminal connected to the reference potential line).

[0023] The node between the source terminal of switching element Q82H and the drain terminal of switching element Q82L is connected to one terminal of inductor 12 through second input terminal P102 of composite power inductor 10.

[0024] The other terminal of the inductor 12 is connected to one terminal of the capacitor 882 through 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.

[0025] A second power conversion circuit is configured by these power semiconductor IC 82 (driver circuit 820, switching element Q82H, switching element Q82L), inductor 12, and capacitor 882. In this way, 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.

[0026] 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 of switching power supply device 80 (the terminal connected to the positive electrode of load 89) through output terminal P103 of composite power inductor 10.

[0027] The capacitor 883 is connected between the high-side output terminal and the low-side output terminal.

[0028] As a result, the inductor 13 and the capacitor 883 form an output filter circuit of the switching power supply device 80. Specifically, the inductor 13 and the capacitor 883 form a low-pass filter for the output current of the power conversion circuit.

[0029] With the above configuration, the switching power supply device 80 comprises a first power conversion circuit and a second power conversion circuit connected in parallel, and an output filter circuit connected to the node between the output terminal of the first power conversion circuit and the output terminal of the second power conversion circuit.

[0030] As a result, the switching power supply device 80 realizes a multi-DC-DC converter using switching elements and can suppress output ripple noise.

[0031] (Composite Power Inductor) FIGS. 2A and 2B are external perspective views of the composite power inductor according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of the composite power inductor according to the first embodiment of the present invention. FIG. 4 is a four-sided view of the composite power inductor according to the first embodiment of the present invention. FIG. 4 shows a plan view (viewing the surface opposite to the mounting surface), a first end view, a second end view, and a first side view. FIG. 5 shows four-sided views (plan view, first end view, second end view, and first side view) of a magnetic body combining a first magnetic body and a second magnetic body according to the first embodiment of the present invention, and a plan view of the first magnetic body. FIG. 6 shows four-sided views (plan view, first end view, second end view, and first side view) of a third magnetic body according to the first embodiment of the present invention. FIG. 7 shows four-sided views (plan view, first end view, second end view, and first side view) of a conductor member according to the first embodiment of the present invention. 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 composite power inductor 10 is arranged on a circuit board.

[0032] 2A, 2B, 3, and 4, 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 the first magnetic member, the magnetic body 22 corresponds to the second magnetic member, and the magnetic body 23 corresponds to the third magnetic member.

[0033] (Magnetic Body) As shown in FIG. 5, the magnetic body 21 and the magnetic body 22 are flat plates.

[0034] 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 planes 2101 and 2102 face each other and are perpendicular to the Z-axis direction (the thickness direction of the magnetic body 21). The end faces 20E1 and 20E2 face each other and are 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). The end faces 20E1 and 20E2 also correspond to the end faces of the magnetic body 20 formed by stacking the magnetic body 21 and the magnetic body 22. The side faces 20S1 and 20S2 face each other and are parallel to the Y-axis direction and perpendicular to the X-axis direction. The side faces 20S1 and 20S2 also correspond to the end faces of the magnetic body 20 formed by stacking the magnetic body 21 and the magnetic body 22.

[0035] The magnetic body 21 includes a groove 211 and a groove 212. The grooves 211 and 212 are recessed from the main plane 2101. The grooves 211 and 212 extend parallel to the Y-axis direction of the magnetic body 21, reach the end faces 20E1 and 20E2, and open to the outside of the magnetic body 21. In the X-axis direction, the distance between the grooves 211 and 212 (the width of the inner leg 10ZI (see FIG. 2A) of the composite power inductor 10) is longer than the distance between the groove 211 and the side surface 20S1 (the width of the outer leg 10ZO1 (see FIG. 2A) of the composite power inductor 10) and the distance between the groove 212 and the side surface 20S2 (the width of the outer leg 10ZO2 (see FIG. 2A) of the composite power inductor 10).

[0036] The grooves 211 and 212 are arranged at an interval in the X-axis direction of the magnetic body 21. The depths of the grooves 211 and 212 are approximately the same as the heights (thicknesses) of the inductor conductors 31 and 32 of the conductor member 30.

[0037] The magnetic body 21 includes a groove 213. The groove 213 extends in the X-axis direction and communicates with an end of the groove 211 and an end of the groove 212 on the end face 20E2 side. The groove 213 opens to the outside of the magnetic body 21 at the end face 20E2 of the magnetic body 21.

[0038] The magnetic body 22 abuts against the main plane 2101 of the magnetic body 21. In this way, the magnetic body 20 having a substantially rectangular parallelepiped shape is formed by stacking the magnetic body 21 and the magnetic body 22.

[0039] 6 , the magnetic body 23 includes a main body 231, a protrusion 232, and a protrusion 233. The main body 231 has a rectangular parallelepiped shape extending in the X-axis direction. The protrusion 232 is formed at one end of the main body 231 in the extension direction and protrudes from the main body 231 in the Y-axis direction. The protrusion 233 is formed at the other end of the main body 231 in the extension direction and protrudes from the main body 231 in the Y-axis direction (the same direction as the protrusion 232).

[0040] The magnetic body 23 is disposed and fixed to the magnetic body 21 so that the tip surfaces of the protrusions 232 and 233 abut against the end surface 20E2 of the magnetic body 21.

[0041] 7 , the conductor member 30 includes inductor conductors 31, 32, 33, connecting conductor 34, terminal conductors 381, 382, ​​391, and 392. The inductor conductors 31, 32, 33, connecting conductor 34, terminal conductors 381, 382, ​​391, and 392 are realized, for example, by forming a single conductive plate of a predetermined thickness by press working or the like. Note that "equal" in this embodiment includes the range of manufacturing error.

[0042] The inductor conductors 31 and 32 are plate-shaped, linear conductors. The width W31 of the inductor conductor 31 is the same as the width W32 of the inductor conductor 32. The width W31 of the inductor conductor 31 and the width W32 of the inductor conductor 32 are the same as the widths of the grooves 211 and 212 in the magnetic body 21.

[0043] The length of the inductor conductor 31 and the length of the inductor conductor 32 are the same as the distance between the end face 20E1 and the end face 20E2 of the magnetic body 21.

[0044] The inductor conductors 31 and 32 extend in the Y-axis direction and are spaced apart in the X-axis direction. That is, the inductor conductors 31 and 32 run parallel to each other. The spacing between the inductor conductors 31 and 32 is the same as the spacing between the grooves 211 and 212 in the magnetic body 21.

[0045] 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 extension 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 extension direction.

[0046] The connecting conductor 34 is a conductor that extends in the X-axis direction and is connected to the other end of the inductor conductor 31 in the extending direction and the other end of the inductor conductor 32 in the extending direction.

[0047] 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 perpendicular to the direction in which the inductor conductors 31 and 32 extend.

[0048] The inductor conductor 33 is disposed between the inductor conductors 31 and 32 in the X-axis direction. The inductor conductor 33 is disposed at approximately the same position in the Y-axis direction as the other ends of the inductor conductors 31 and 32 in the extending direction. The inductor conductor 33 is disposed on the same side as the terminal conductors 381 and 382 with respect to the inductor conductors 31 and 32 in the Z-axis direction.

[0049] The inductor conductor 33 is connected to the other end of the inductor conductor 31 and the other end of the inductor conductor 32 through the connecting conductor 34 .

[0050] 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 (W33>W31=W32).

[0051] 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 of the inductor conductor 31 in the extension direction. The terminal conductor 392 is a plate-shaped conductor extending in the Z-axis direction. The terminal conductor 392 is connected to one end of the inductor conductor 32 in the extension direction. The terminal conductors 391 and 392 are arranged on the same side as the inductor conductors 33, 381, and 382 in the Z-axis direction with respect to the inductor conductors 31 and 32.

[0052] (Specific Structure of Composite Power Inductor) As shown in FIGS. 2A, 2B, and 3, the conductor member 30 is disposed on the magnetic body 21 such that the inductor conductors 31 and 32 fit into the grooves 211 and 212 of the magnetic body 21, respectively. The connection conductor 34 of the conductor member 30 is disposed along the groove 213 of the magnetic body 21 so that at least a portion of the connection conductor 34 fits into the groove 213. The inductor conductor 33, terminal conductors 391, and terminal conductors 392 of the conductor member 30 abut against the end face 20E2 of the magnetic body 21. The terminal conductors 381 and 382 of the conductor member 30 abut against the end face 20E1 of the magnetic body 21. Note that the terminal conductors 391 and 392 do not necessarily have to abut against the end face 20E2. Similarly, the terminal conductors 381 and 382 do not necessarily have to abut against the end face 20E1.

[0053] The tip of the terminal conductor 381 (the end opposite the connection end to the inductor conductor 31) and the tip of the terminal conductor 382 (the end opposite the connection end to the inductor conductor 32) are approximately flush with the main plane 2102 of the magnetic body 21.

[0054] The tip of the terminal conductor 391 (the end opposite the connection end to the inductor conductor 31) and the tip of the terminal conductor 392 (the end opposite the connection end to the inductor conductor 32) are approximately flush with the main plane 2102 of the magnetic body 21.

[0055] The tip end of the inductor conductor 33 (the end opposite to the end connected to the inductor conductors 31 and 32 through the connecting conductor 34 ) is substantially flush with the main plane 2102 of the magnetic body 21 .

[0056] The magnetic body 23 is disposed so as 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 fits between the protrusions 232 and 233.

[0057] With this configuration, the inductor conductors 31 and 32 are surrounded by a laminate of the magnetic materials 21 and 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.

[0058] Furthermore, the inductor conductor 33 is surrounded by the magnetic body 21 and the magnetic body 23 .

[0059] (Connection Relationship Between the Composite Power Inductor 10 and Other Circuit Elements of the Switching Power Supply Device 80) The tip of the terminal conductor 381 is connected to the node between the switching element Q81H and the switching element Q81L of the power semiconductor IC 81. In terms of an equivalent circuit, the terminal conductor 381 is the first input terminal P101 of the composite power inductor 10. In terms of an equivalent circuit, the inductor conductor 31 is the inductor 11 of the composite power inductor 10, and corresponds to the first inductor conductor of the present invention.

[0060] The tip of the terminal conductor 382 is connected to the node between the switching element Q82H and the switching element Q82L of the power semiconductor IC 82. In terms of an equivalent circuit, the tip of the terminal conductor 382 is the second input terminal P102 of the composite power inductor 10. In terms of an equivalent circuit, the inductor conductor 32 is the inductor 12 of the composite power inductor 10, and corresponds to the second inductor conductor of the present invention.

[0061] 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 terms of the equivalent circuit. The inductor conductor 33 is the inductor 13 of the composite power inductor 10 in terms of the equivalent circuit, and corresponds to the third inductor conductor of the present invention.

[0062] 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 terms of an equivalent circuit, and the terminal conductor 391 corresponds to the first capacitor terminal conductor of the present invention.

[0063] The tip end of the terminal conductor 392 is connected to one terminal of the capacitor 882. The tip end of the terminal conductor 392 is the second capacitor terminal P192 of the composite power inductor 10 in terms of an equivalent circuit, and the terminal conductor 392 corresponds to the second capacitor terminal conductor of the present invention.

[0064] (Current and magnetic field of composite power inductor) Figures 8(A), 8(B), and 8(C) are diagrams simply 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 perspective view, Figure 8(B) is a plan view, and Figure 8(C) is an end view.

[0065] 8A, 8B, and 8C, when the switching power supply device 80 operates, currents flow in the same direction through the inductor conductor 31 and the inductor conductor 32. Specifically, current I31 flows through the inductor conductor 31 from the end face 20E2 to the end face 20E1, and current I32 flows through the inductor conductor 32 from the end face 20E2 to the end face 20E1, with the currents I31 and I32 flowing in the same direction.

[0066] As a result, in the inner leg 10ZI between the inductor conductors 31 and 32, the direction of the magnetic field H31 generated by the current I31 in the inductor conductor 31 is opposite to the direction of the magnetic field H32 generated by the current I32 in the inductor conductor 32. As a result, the magnetic flux due to the current I31 in the inductor conductor 31 and the magnetic flux due to the current I32 in the inductor conductor 32 cancel each other out. This reduces the magnetic flux density in the inner leg 10ZI and suppresses magnetic saturation. As a result, the distance between the inductor conductors 31 and 32 can be shortened, in other words, the width of the inner leg 10ZI can be narrowed. Therefore, the composite power inductor 10 can be miniaturized while suppressing characteristic degradation.

[0067] The directions of the magnetic fields H31 and H32 in the outer legs 10ZO1 are the same, and the directions of the magnetic fields H31 and H32 in the outer legs 10ZO2 are the same. As a result, in the outer legs 10ZO1 and 10ZO2, the magnetic flux due to the current I31 in the inductor conductor 31 and the magnetic flux due to the current I32 in the inductor conductor 32 reinforce each other. Therefore, the characteristics of the composite power inductor 10 can be improved without increasing the size of the device.

[0068] 8(A), 8(B), and 8(C), when the switching power supply device 80 operates, a current I33 flows through the inductor conductor 33 in a direction parallel to the lamination direction of the magnetic bodies 21 and 22. That is, the direction of the current I33 flowing through the inductor conductor 33 is perpendicular to the direction of the current I31 flowing through the inductor conductor 31 and the direction of the current I32 flowing through the inductor conductor 32.

[0069] As a result, the plane formed by the magnetic field H33 due to the current I33 is perpendicular to the plane formed by the magnetic field H31 due to the current I31 and the plane formed by the magnetic field H32 due to the current I32. Therefore, the magnetic flux due to the current I33 is not substantially coupled to the magnetic flux due to the current I31 and the magnetic flux due to the current I32, and the magnetic flux density does not increase. As a result, magnetic saturation of the inductor conductor 33 is suppressed, and the output filter circuit including the inductor conductor 33 (inductor 13) can achieve desired filter characteristics without increasing the size of the composite power inductor 10.

[0070] As described above, according to the configuration of this embodiment, the composite power inductor 10 can be realized in a physically small size, and the desired characteristics can be achieved as the composite power inductor 10 and the switching power supply device 80. Furthermore, the composite power inductor 10 realizes the inductors of the multiple power conversion circuits and the inductors of the output filter circuit in a single housing, which reduces the number of components compared to conventional configurations in which the inductors of the multiple power conversion circuits and the inductors of the output filter circuit are provided individually. In other words, the functions realized by multiple power inductors can be configured with a single integrated composite power inductor, and magnetic saturation of the magnetic material can be suppressed by canceling out the magnetic flux generated by the DC output current, and output voltage ripple can be reduced by configuring a low-pass filter for the output current.

[0071] Furthermore, in the configuration of this embodiment, the inductor conductors 31 and 32 are surrounded by a laminate of the magnetic bodies 21 and 22. This allows the inductance of the inductor 11 due to the inductor conductor 31 and the inductance of the inductor 12 due to the inductor conductor 32 to be increased without changing the shape. Also, the magnetic flux due to the current I31 in the inductor conductor 31 and the magnetic flux due to the inductor conductor 32 are concentrated inside the laminate of the magnetic bodies 21 and 22 and are less likely to leak to the outside. Therefore, the composite power inductor 10 can be made compact while suppressing external impact.

[0072] Similarly, the inductor conductor 33 is surrounded by the magnetic body 21 and the magnetic body 23. This allows the inductance of the inductor 13 due to the inductor conductor 33 to be increased without changing the shape. Furthermore, the magnetic flux due to the current I33 of the inductor conductor 33 is concentrated inside the structure made up of the magnetic body 21 and the magnetic body 23, and is less likely to leak to the outside. Therefore, the composite power inductor 10 can be made compact while preventing the magnetic flux of the inductor conductor 33 from coupling with the terminal conductors 391 and 392, and further reducing its impact on the outside.

[0073] 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 combined 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.

[0074] However, since the width W33 of the inductor conductor 33 is large, the resistance to the current I33 can be reduced even if the current I33 is large, and the composite power inductor 10 can suppress transmission loss and heat loss in the inductor conductor 33.

[0075] Furthermore, 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. As a result, even if the current I33 is large, the resistance to the current I33 can be reduced, and the composite power inductor 10 can suppress transmission loss and heat loss in the inductor conductor 33.

[0076] (Structural example of a switching power supply device) Fig. 9 is a perspective view showing an example of a switching power supply device according to the first embodiment of the present invention. As shown in Fig. 9, a 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.

[0077] The circuit board 800 has a component mounting surface and a ground surface. On the component mounting surface, a connecting conductor pattern 801, a connecting conductor pattern 802, a connecting conductor pattern 803, a connecting conductor pattern 804, and a connecting conductor pattern 805, each of which is formed in a film shape, are formed. Furthermore, on the component mounting surface, a plurality of ground conductor patterns 809, each of which is formed in a film shape, are formed. On the ground surface, a ground conductor pattern 890 is formed. The ground conductor pattern 890 is formed in a position overlapping at least a plurality of ground conductor patterns 809 when the circuit board 800 is viewed in a plane, and is formed, for example, over substantially the entire surface.

[0078] The power semiconductor IC81 and the power semiconductor IC82 are arranged on the end face 20E2 side of the composite power inductor 10. The power semiconductor IC81 and the power semiconductor IC82 are arranged along the end face 20E2, with the power semiconductor IC81 arranged in a position close to the terminal conductor 381 of the composite power inductor 10 and the power semiconductor IC82 arranged in a position close to the terminal conductor 382 of the composite power inductor 10.

[0079] The power semiconductor IC 81 and the terminal conductor 381 are mounted on and electrically and physically connected to the connecting conductor pattern 801. The power semiconductor IC 82 and the terminal conductor 382 are mounted on and electrically and physically connected to the connecting conductor pattern 802.

[0080] The plurality of capacitors 881, the plurality of capacitors 882, and the plurality of capacitors 883 are arranged on the end face 20E1 side of the composite power inductor 10. The plurality of capacitors 881 are arranged at a position close to the terminal conductor 391 of the composite power inductor 10, the plurality of capacitors 882 are arranged at a position close to the terminal conductor 392 of the composite power inductor 10, and the plurality of capacitors 883 are arranged at a position close to the inductor conductor 33 of the composite power inductor 10.

[0081] The inductor conductor 33 and the plurality of capacitors 883 are mounted on and electrically and physically connected to the connecting conductor pattern 803. The terminal conductor 391 and the plurality of capacitors 881 are mounted on and electrically and physically connected to the connecting conductor pattern 804. The terminal conductor 392 and the plurality of capacitors 882 are mounted on and electrically and physically connected to the connecting conductor pattern 805.

[0082] A plurality of capacitors 881, a plurality of capacitors 882, and a plurality of capacitors 883 are mounted on the ground conductor pattern 809, and are electrically connected to the reference potential.

[0083] With this configuration, the switching power supply device 80 can be realized in a space-saving shape.

[0084] [Second Embodiment] A composite power inductor according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 10 is an exploded perspective view of the composite power inductor according to the second embodiment of the present invention. Fig. 11 is an external perspective view of the composite power inductor according to the second embodiment of the present invention.

[0085] 10 and 11 , 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. Other configurations of the composite power inductor 10A are similar to those of the composite power inductor 10, and a description of similar parts will be omitted.

[0086] 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 in the Z-axis direction with respect to the inductor conductors 31 and 32. As a result, the inductor conductor 33A abuts against the end face of the magnetic body 22.

[0087] The magnetic body 23 is fixed to the end face of the magnetic body 22 so as to surround the inductor conductor 33A.

[0088] With this configuration, similar 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 achieved as the composite power inductor 10A.

[0089] Furthermore, in this configuration, the inductor conductor 33A is not sandwiched between the terminal conductors 391 and 392. This allows the width of the inductor conductor 33A to be increased, thereby enabling the composite power inductor 10A to suppress various losses due to current.

[0090] Furthermore, in this configuration, the length of the inductor conductor 33A does not need to be the same as the lengths of the terminal conductors 391 and 392. This allows the composite power inductor 10A to adjust the inductance of the inductor conductor 33A and adjust the filter characteristics of the output filter circuit.

[0091] [Third Embodiment] A composite power inductor according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 12 is a perspective view showing the appearance of the composite power inductor according to the third embodiment of the present invention.

[0092] 12 , the composite power inductor 10B according to the third embodiment differs from the composite power inductor 10 according to the first embodiment in that the magnetic body 23 is omitted. Other configurations of the composite power inductor 10B are similar to those of the composite power inductor 10, and a description of similar parts will be omitted.

[0093] The conductor member 30B of the composite power inductor 10B includes an inductor conductor 33B. The inductor conductor 33B abuts against the end face 20E1 of the magnetic body 21 and is exposed to the outside except for this abutment surface. With this configuration, the inductance of the inductor 13 can be reduced by the inductor conductor 33B. This allows the composite power inductor 10B to adjust the filter characteristics of the output filter circuit.

[0094] Furthermore, this configuration does not require a space for inserting a magnetic body between the inductor conductor 33B and the terminal conductor 391. Similarly, this configuration does not require a space for inserting a magnetic body between the inductor conductor 33B and the terminal conductor 391. This allows the width of the inductor conductor 33B to be increased, and the composite power inductor 10B can suppress various losses due to current.

[0095] [Fourth Embodiment] A composite power inductor according to a fourth embodiment of the present invention will be described with reference to the drawings. Fig. 13 is an exploded perspective view of the composite power inductor according to the fourth embodiment of the present invention. Fig. 14 is an external perspective view of the composite power inductor according to the fourth embodiment of the present invention.

[0096] 13 and 14 , the composite power inductor 10C according to the fourth embodiment differs from the composite power inductor 10 according to the first embodiment in a magnetic body 21C, a magnetic body 23C, and a conductor member 30C. The other configuration of the composite power inductor 10C is the same as that of the composite power inductor 10, and a description of similar parts will be omitted.

[0097] The composite power inductor 10C includes a magnetic body 21C, a magnetic body 23C, and a conductive member 30C.

[0098] The magnetic body 21C differs from the magnetic body 21 according to 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 has a rectangular parallelepiped shape. The through hole 214C is formed at a position farther from the end face 20E1 than the groove 213 (at a position closer to the end face 20E2). The through hole 214C penetrates between the bottom surfaces of the grooves 213, 211, and 212 and the main flat surface 2102 of the magnetic body 21C. In other words, it penetrates the magnetic body 21C in the thickness direction (Z-axis direction).

[0099] The conductor member 30C includes an inductor conductor 33C and a connecting conductor 34C. The inductor conductor 33C is disposed at a position offset toward one end from the other ends (the ends connected to the terminal conductors 391 and 392, respectively) of the inductor conductors 31 and 32. The inductor conductor 33C is connected to the inductor conductors 31 and 32 via the connecting conductor 34C.

[0100] The conductor member 30C is disposed on the magnetic body 21C such that the inductor conductor 31 fits into the groove 211, the inductor conductor 32 fits into the groove 212, and the inductor conductor 33C passes through the through-hole 214C.

[0101] The magnetic body 23C has a rectangular parallelepiped shape and is fitted into the groove 213.

[0102] With this configuration, the composite power inductor 10C has the inductor conductor 31, the inductor conductor 32, and the inductor conductor 33C arranged inside the laminate of the magnetic body 21C and the magnetic body 22. This allows the composite power inductor 10C to achieve characteristics equivalent to those of the composite power inductor 10, even without having a part that protrudes outward from the laminate of the magnetic body 21 and the magnetic body 22, such as the magnetic body 23 of the composite power inductor 10. Therefore, the composite power inductor 10C is smaller than the composite power inductor 10, yet can achieve the same effects as those of the composite power inductor 10.

[0103] The configurations of the above-described embodiments can be combined as appropriate, and effects according to each combination can be achieved.

[0104] <1> An inductor conductor comprising a linear first inductor conductor, a linear second inductor conductor, and a third inductor conductor; and one magnetic body forming a magnetic path for magnetic flux generated by current flowing through the first inductor conductor, the second inductor conductor, and the third inductor conductor, wherein one end of the first inductor conductor is connected to a 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 a 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 or contained within the magnetic body, and the first inductor conductor and the second inductor conductor are arranged in parallel such that, at an inner leg portion of the magnetic body between the first inductor conductor and the second inductor conductor, magnetic flux generated by the current flowing in each conductor cancels out, and at outer leg portions of the magnetic body that are outer than the first inductor conductor and the second inductor conductor, magnetic flux generated by the current flowing in each conductor is reinforced, a switching power supply device equipped with a composite power inductor, wherein the third inductor conductor is arranged so that a plane formed by a magnetic flux generated by a current flowing through the third inductor conductor is perpendicular to planes formed by magnetic flux generated by a current flowing through the first inductor conductor and the second inductor conductor, the first inductor conductor and the second inductor conductor are inductors that constitute a power conversion circuit, and the third inductor conductor is an inductor that constitutes a low-pass filter for the output current of the power conversion circuit.

[0105] <2> A switching power supply device including the composite power inductor of <1>, wherein the magnetic body includes a first magnetic member and a second magnetic member having overlapping portions, and a portion of the first inductor conductor and a portion of the second inductor conductor are sandwiched between or enclosed by the first magnetic member and the second magnetic member.

[0106] <3> A switching power supply device comprising the composite power inductor of <1> or <2>, wherein the first magnetic member has a through hole, and at least a portion of the third inductor conductor passes through the through hole.

[0107] <4> A switching power supply device including the composite power inductor of <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 or the second magnetic member, and 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.

[0108] <5> A switching power supply device comprising the composite power inductor according to any one of <1> to <4>, wherein the first inductor conductor and the second inductor conductor are longer than the third inductor conductor.

[0109] <6> A switching power supply device including the composite power inductor according to any one of <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.

[0110] <7> A switching power supply device including the composite power inductor according to any one of <1> to <6>, comprising: a first capacitor terminal conductor connected to the other end of the first inductor conductor and one end of the third inductor conductor; and a second capacitor terminal conductor connected to the other end of the second inductor conductor and one end of the third inductor conductor.

[0111] <8> A switching power supply device including the composite power inductor of <7>, wherein the magnetic body has a main plane and first and second end faces that 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, and the third inductor conductor, the first capacitor terminal conductor, and the second capacitor terminal conductor are arranged along the first end face.

[0112] <9> A switching power supply device including the composite power inductor of <8>, comprising: a circuit board on which the composite power inductor is mounted and which has a ground conductor pattern; and a first capacitor element, a second capacitor element, and a third capacitor element mounted on the circuit board, wherein 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, and the third capacitor element is connected between the other end of the third inductor conductor and the ground conductor pattern.

[0113] <10> A switching power supply device equipped with the composite power inductor of any one of <1> to <9>, comprising: 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 an output filter circuit including a third inductor using the third inductor conductor.

[0114] Q81H, Q81L, Q82H, Q82L: Switching element 10, 10A, 10B, 10C: Composite power inductor 10ZI: Inner leg portion 10ZO1, 10ZO2: Outer leg portion 11, 12, 13: Inductor 20, 21, 21C, 22, 23, 23C: Magnetic body 20E1, 20E2: End face 20S1, 20S2: Side face 30, 30A, 30B, 30C: Conductor member 31, 32, 33, 33A, 33B, 33C: Inductor conductor 34, 34C: Connecting conductor 80: Switching power supply device 81, 82: Power semiconductor IC 89: Load 211, 212, 213: Groove 214C: Through hole 231: Main body 232, 233: Protrusion 381, 382, ​​391, 392: Terminal conductors 800: Circuit board 801, 802, 803, 804, 805: Connecting conductor patterns 809: Ground conductor pattern 810, 820: Driver circuits 881, 882, 883: Capacitors 890: Ground conductor pattern 2101, 2102: Main surfaces P101: First input terminal P102: Second input terminal P103: Output terminal P191: First capacitor terminal P192: Second capacitor terminal

Claims

1. a first inductor conductor having a linear shape; a second inductor conductor having a linear shape; A third inductor conductor; a magnetic body that forms a magnetic path for a magnetic flux generated by a current flowing through the first inductor conductor, the second inductor conductor, and the third inductor conductor; Equipped with one end of the first inductor conductor is connected to a 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 a 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 or enclosed within the magnetic body; The first inductor conductor and the second inductor conductor are 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 are cancelled out, In the outer leg portion of the magnetic body that is outside the first inductor conductor and the second inductor conductor, the magnetic fluxes generated by the currents flowing through the respective conductors are reinforced. They are arranged side by side, the third inductor conductor is arranged such that a plane formed by a magnetic flux generated by a current flowing through the third inductor conductor is perpendicular to a plane formed by a magnetic flux generated by a current flowing through the first inductor conductor and a plane formed by a magnetic flux generated by a current flowing through the second inductor conductor; the first inductor conductor and the second inductor conductor are inductors that configure a power conversion circuit, The third inductor conductor is an inductor that constitutes a low-pass filter for the output current of the power conversion circuit. A switching power supply with a composite power inductor.

2. the magnetic body includes a first magnetic member and a second magnetic member having overlapping portions, a portion of the first inductor conductor and a portion of the second inductor conductor are sandwiched between or enclosed by the first magnetic member and the second magnetic member; A switching power supply comprising the composite power inductor according to claim 1.

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

4. the magnetic body includes a third magnetic member having a portion overlapping 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. A switching power supply device comprising the composite power inductor according to claim 1 or 2.

5. the first inductor conductor and the second inductor conductor are longer than the third inductor conductor; A switching power supply device comprising the composite power inductor according to claim 1 or 2.

6. At least a portion of the third inductor conductor is wider than the first inductor conductor and the second inductor conductor. A switching power supply device comprising the composite power inductor according to claim 1 or 2.

7. a first capacitor terminal conductor connected to the other end of the first inductor conductor and one end of the third inductor conductor; a second capacitor terminal conductor connected to the other end of the second inductor conductor and one end of the third inductor conductor; Equipped with A switching power supply device comprising the composite power inductor according to claim 1 or 2.

8. The magnetic body is A main plane; a first end surface and a second end surface perpendicular to the main plane and facing each other; the first inductor conductor and the second inductor conductor are disposed along the major plane; the third inductor conductor, the first capacitor terminal conductor, and the second capacitor terminal conductor are arranged along the first end surface. A switching power supply comprising the composite power inductor according to claim 7.

9. a circuit board on which the composite power inductor is mounted and which has a ground conductor pattern; a first capacitor element, a second capacitor element, and a third capacitor element mounted on the circuit board; Equipped with 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; A switching power supply comprising the composite power inductor according to claim 8.

10. 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; an output filter circuit including a third inductor using the third inductor conductor; 3. A switching power supply device comprising the composite power inductor according to claim 1 or 2.