Inductors and DC-DC converters

Abstract

To provide an inductor and a DC-DC converter that are designed to suppress crack formation. [Solution] The inductor 1 comprises a base body 90 made of a base material including resin, a magnetic block 2 provided inside the base body 90, a coil conductor 3 provided inside the base body 90, and terminal portions 7A and 7B extending from the ends of the conductor portions 4A and 4B of the coil conductor 3 on the lower surface 90f side toward the first side surface 90a of the base body 90 and facing the lower surface 2f of the magnetic block 2. The gap G between the lower surface 2f of the magnetic block 2 and the terminal portions 7A and 7B is filled with the base material that constitutes the base body 90. Therefore, in a high-temperature environment where the magnetic block 2 undergoes thermal expansion in the Z-axis direction, the magnetic block 2 does not directly press the terminal portions 7A and 7B downward, and the occurrence of the aforementioned cracks 92 in the base body 90 is suppressed.

Description

Technical Field

[0001] The present disclosure relates to an inductor and a DC-DC converter.

Background Art

[0002] Patent Document 1 discloses an inductor having a configuration in which a coil conductor and a magnetic body are arranged side by side within an element body made of magnetic powder-containing resin. Terminal portions extending from the coil conductor are exposed on the mounting surface of the element body that faces a circuit board on which the inductor is surface-mounted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described inductor, when the terminal portions are configured to extend toward the magnetic body in the vicinity of the mounting surface, a configuration in which the magnetic body is directly placed on the terminal portions can be obtained. In such a configuration, if the magnetic body thermally expands in a direction orthogonal to the mounting surface under a high-temperature environment, the terminal portions are pressed downward by the magnetic body, and as a result, cracks may occur in the element body.

[0005] An aspect of the present disclosure aims to provide an inductor and a DC-DC converter in which the occurrence of cracks is suppressed.

Means for Solving the Problems

[0006] An inductor relating to one aspect of the present disclosure comprises a base body made of a base material including resin, having a first side and a second side facing each other in a first direction, and a first main surface and a second main surface facing each other in a second direction perpendicular to the first direction; a first magnetic body provided within the base body, having a first surface facing the first side and a second surface facing the second side, a third surface facing the first main surface and a fourth surface facing the second main surface in a second direction; a first coil conductor provided within the base body, with at least a portion facing the second surface of the first magnetic body; and a first terminal portion extending from the end of the first coil conductor on the first main surface side toward the first side and facing the third surface of the first magnetic body, with at least a portion exposed from the first main surface of the base body, wherein the gap between the third surface of the first magnetic body and the first terminal portion is filled with the base material.

[0007] A DC-DC converter relating to one aspect of this disclosure includes the above-mentioned inductor. [Effects of the Invention]

[0008] According to one aspect of this disclosure, an inductor and a DC-DC converter are provided in which crack occurrence is suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of an inductor according to one embodiment. [Figure 2] Figure 1 is an exploded view of the inductor shown. [Figure 3] Figure 1 is a cross-sectional view of the inductor shown along line III-III. [Figure 4] Figure 1 is a side view of the inductor shown. [Figure 5] This diagram shows cracks that can occur on the side surface of an inductor. [Figure 6] This is a cross-sectional view showing an inductor in a different configuration than that shown in Figure 3. [Figure 7] This diagram shows the circuit of a DC-DC converter using the inductor shown in Figure 1. [Modes for carrying out the invention]

[0010] Several embodiments of this disclosure are described in detail below. However, this disclosure is not limited to the embodiments described below.

[0011] First, the schematic configuration of the inductor 1 in this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the inductor 1 in this embodiment. Figure 2 is an exploded view of the inductor 1. Note that Figure 1 shows the inductor 1 mounted on a substrate 101. The inductor 1 in this embodiment is composed of a base body 90, magnetic blocks 2 provided within the base body 90, coil conductors 3, and terminal portions 7. More specifically, it is composed of three core magnetic blocks 2, a pair of coil conductors 3, and a pair of terminal portions 7 corresponding to each of the pair of coil conductors 3. In other words, the inductor 1 according to this embodiment is a composite inductor provided with two inductors.

[0012] The pair of coil conductors 3 (3A and 3B) included in inductor 1 can be used as the choke coils in the DC-DC converter 500 circuit shown in Figure 7. The DC-DC converter 500 is a multi-phase converter in which a pair of conversion sections consisting of switching elements SW1 and SW2, choke coils 520A and 520B, and diodes D1 and D2 are connected in parallel, and the above-mentioned inductor 1 can be used as the choke coils 520A and 520B in each conversion section. To describe the configuration of the DC-DC converter 500 in more detail, the DC-DC converter 500 includes a pair of input terminals A1 and A2, a pair of output terminals B1 and B2, a switching element SW1 and choke coil 520A connected in series between input terminal A1 and output terminal B1 in that order, a switching element SW2 and choke coil 520B connected in series between input terminal A1 and output terminal B1 in that order, and a capacitor C1 connected between output terminals B1 and B2. A circuit consisting of switching element SW1 and choke coil 520A, and a circuit consisting of switching element SW2 and choke coil 520B are connected in parallel between input terminal A1 and output terminal B1. Input terminal A2 and output terminal B2 form a ground line. Diode D2 is connected in reverse between the connection point of switching element SW1 and choke coil 520A and the ground line, and diode D1 is connected in reverse between the connection point of switching element SW2 and choke coil 520B and the ground line. Switching elements SW1 and SW2 are alternately switched on and off by a control circuit (not shown), thereby generating an output voltage obtained by stepping down the input voltage. By replacing the pair of choke coils 520A and 520B in the DC-DC converter 500 with the pair of coil conductors 3A and 3B of the inductor 1, the number of components constituting the DC-DC converter 500 can be reduced.

[0013] As shown in Figure 1, the base body 90 has a roughly rectangular parallelepiped shape. In this embodiment, the shape of the base body 90 is composed of three pairs of faces that face each other in the mutually orthogonal X-axis, Y-axis, and Z-axis directions. That is, the shape of the base body 90 has a first side surface 90a and a second side surface 90b that face each other in the X-axis direction, a third side surface 90c and a fourth side surface 90d that face each other in the Y-axis direction, and an upper surface 90e (second main surface) and a lower surface 90f (first main surface) that face each other in the Z-axis direction. The X-axis direction corresponds to the "first direction" in the claim, the Z-axis direction corresponds to the "second direction" in the claim, and the Y-axis direction corresponds to the "third direction" in the claim. Note that the rectangular parallelepiped shape includes the shape of a rectangular parallelepiped with chamfered corners and edges, and the shape of a rectangular parallelepiped with rounded corners and edges. Furthermore, as in this embodiment, the terminal portion 7 is exposed from the lower surface 90f of the base body 90, resulting in a step on the lower surface 90f of the base body 90. However, the rectangular parallelepiped shape also includes base bodies 90 that include such a step.

[0014] The base body 90 is composed of a base material containing resin, and the resin of the base material may be a thermosetting resin such as epoxy. The base material according to this embodiment contains a magnetic material, and as the magnetic material, it contains magnetic powder. More specifically, the base material according to this embodiment is composed of a mixture of soft magnetic metal powder and resin, and is a composite material in which soft magnetic metal powder is dispersed in a binder resin. As the soft magnetic metal powder, iron-silicon alloy, permalloy, sendust, amorphous, nanocrystalline alloy, or a mixture thereof can be used. Furthermore, if the base material contains magnetic powder, the magnetic permeability of the base material may be 5 or more, and may be 20 or more. In addition, the magnetic permeability of the base material may be 100 or less, and may be 50 or less. The base material may have a lower magnetic permeability than the magnetic block 2.

[0015] The three magnetic blocks 2 consist of a first magnetic block 2A, a second magnetic block 2B, and a third magnetic block 2C. Magnetic blocks 2A and 2B are arranged facing each other, spaced apart in the X-axis direction. Magnetic blocks 2B and 2C are also arranged facing each other, spaced apart in the X-axis direction. Magnetic blocks 2A, 2B, and 2C are arranged in this order from the negative side in the X-axis direction. The magnetic blocks 2 have a roughly rectangular parallelepiped shape. In this embodiment, they have a rectangular parallelepiped shape that is flattened in the X-axis direction. The magnetic blocks 2 may have the same shape. Note that the first magnetic block 2A, the second magnetic block 2B, and the third magnetic block 2C may each have different shapes, and the first magnetic block 2A and the third magnetic block 2C may have the same shape, while the first magnetic block 2A and the third magnetic block 2C and the second magnetic block 2B may have different shapes. Furthermore, the magnetic blocks 2 may have shapes other than rectangular parallelepipeds.

[0016] The magnetic block 2 according to this embodiment is a laminated magnetic core having a laminated structure in which a plurality of soft magnetic metal plates are stacked in the Z-axis direction via a resin layer. The number of layers of soft magnetic metal plates constituting the magnetic block 2 is, as an example, 120. The soft magnetic metal plates can be composed of magnetic alloys such as amorphous alloys, microcrystalline alloys, permalloys, and alloys consisting of nanoheterostructures. Amorphous alloy materials include Fe-based amorphous soft magnetic materials and Co-based amorphous soft magnetic materials, while microcrystalline alloys include Fe-based nanocrystalline soft magnetic materials. A nanoheterostructure refers to a structure in which microcrystals exist within an amorphous material. The resin layer included in the magnetic block 2 can be made of materials such as epoxy resin, polyimide resin, polyimideamide resin, or silicone resin. The magnetic block 2 can be configured to have a relatively high magnetic permeability, and can be designed to have a higher magnetic permeability than the magnetic permeability of the base material constituting the base body 90. The magnetic permeability of the magnetic block 2 may be 1000 or more. Furthermore, the magnetic properties of the magnetic block 2 may be substantially the same or different. Since magnetic block 2 has a laminated structure in which multiple soft magnetic metal plates are stacked in the Z-axis direction via a resin layer, the coefficient of thermal expansion in the Z-axis direction is greater than the coefficients of thermal expansion in the X-axis and Y-axis directions.

[0017] Each of the three magnetic blocks 2A to 2C has a pair of main surfaces 2a, 2b, a pair of end surfaces 2c, 2d, and a pair of side surfaces 2e, 2f. The pair of main surfaces 2a, 2b face each other in the X-axis direction. The main surface 2a is disposed on the negative side in the X-axis direction which is the first side surface 90a side of the element body 90, and the main surface 2b is disposed on the positive side in the X-axis direction which is the second side surface 90b side of the element body 90. The pair of end surfaces 2c, 2d face each other in the Y-axis direction. The end surface 2c is disposed on the positive side in the Y-axis direction, and the end surface 2d is disposed on the negative side in the Y-axis direction. The pair of side surfaces 2e, 2f face each other in the Z-axis direction. The side surface 2e corresponds to the upper surface of the magnetic block disposed on the positive side in the Z-axis direction which is the upper surface 90e side of the element body 90, and the side surface 2f corresponds to the lower surface of the magnetic block disposed on the negative side in the Z-axis direction which is the lower surface 90f side of the element body 90. The facing direction of the pair of main surfaces 2a, 2b may completely coincide with the X-axis direction, or may be inclined to some extent from the X-axis direction. The facing direction of the pair of end surfaces 2c, 2d may completely coincide with the Y-axis direction, or may be inclined to some extent from the Y-axis direction. The facing direction of the pair of side surfaces 2e, 2f may completely coincide with the Z-axis direction, or may be inclined to some extent from the Z-axis direction.

[0018] The two coil conductors 3 are composed of a first coil conductor 3A and a second coil conductor 3B. The first coil conductor 3A and the second coil conductor 3B are arranged side by side along the X-axis direction with the second magnetic block 2B interposed therebetween. The first coil conductor 3A is disposed between the first magnetic block 2A and the second magnetic block 2B, and the second coil conductor 3B is disposed between the second magnetic block 2B and the third magnetic block 2C. The material of the coil conductor 3 is, for example, a metal selected from Cu, Ag, Au, Al, Ni, Sn and the like.

[0019] The first coil conductor 3A includes a pair of conductor portions 4A, 4B and a connecting portion 6. The pair of conductor portions 4A, 4B respectively correspond to the "first conductor portion" and the "second conductor portion" in the claims, and the connecting portion 6 corresponds to the "connecting conductor portion" in the claims.

[0020] Each of the conductor portions 4A and 4B extends in the Z-axis direction and is parallel to each other. The conductor portions 4A and 4B are disposed between the first magnetic block 2A and the second magnetic block 2B in the X-axis direction. The conductor portion 4A is disposed on the positive side in the Y-axis direction, and the conductor portion 4B is disposed on the negative side in the Y-axis direction. The conductor portions 4A and 4B do not need to be parallel to the Z-axis direction as long as they extend in the Z-axis direction.

[0021] The conductor portion 4A has a pair of opposing surfaces 4Aa and 4Ab, and a pair of side surfaces 4Ac and 4Ad. The pair of opposing surfaces 4Aa and 4Ab face each other in the X-axis direction. The opposing surface 4Aa disposed on the negative side in the X-axis direction faces the first magnetic block 2A in the X-axis direction. The opposing surface 4Ab disposed on the positive side in the X-axis direction faces the second magnetic block 2B in the X-axis direction. The side surfaces 4Ac and 4Ad face each other in the Y-axis direction. The side surface 4Ac is disposed on the positive side in the Y-axis direction, and the side surface 4Ad is disposed on the negative side in the Y-axis direction. The conductor portion 4B has a pair of opposing surfaces 4Ba and 4Bb, and a pair of side surfaces 4Bc and 4Bd. The pair of opposing surfaces 4Ba and 4Bb face each other in the X-axis direction. The opposing surface 4Ba disposed on the negative side in the X-axis direction faces the first magnetic block 2A in the X-axis direction. The opposing surface 4Bb disposed on the positive side in the X-axis direction faces the second magnetic block 2B in the X-axis direction. The side surfaces 4Bc and 4Bd face each other in the Y-axis direction. The side surface 4Bc is disposed on the negative side in the Y-axis direction, and the side surface 4Bd is disposed on the positive side in the Y-axis direction.

[0022] The connecting portion 6 is a member that connects the conductor portion 4A and the conductor portion 4B. The connecting portion 6 is connected to one end of each of the conductor portions 4A and 4B (that is, the end portion on the positive side in the Z-axis direction), and extends in the Y-axis direction. The connecting portion 6 does not need to be parallel to the Y-axis direction as long as it extends in the Y-axis direction. In the present embodiment, as shown in FIG. 4, the side surface 2e of the first magnetic block 2A is located on the lower surface 90f side (the negative side in the Z-axis direction) relative to the lower surface of the connecting portion 6 (that is, the surface on the negative side in the Z-axis direction).

[0023] A pair of terminal portions 7 are connected to the first coil conductor 3A. The pair of terminal portions 7 may be provided integrally with the first coil conductor 3A or as separate components. The pair of terminal portions 7 connected to the first coil conductor 3A each correspond to the "first terminal portion" in the claims. The pair of terminal portions 7 consists of terminal portion 7A and terminal portion 7B. Terminal portion 7A is connected to the first coil conductor 3A and is provided at the other end of the conductor portion 4A (i.e., the negative end in the Z-axis direction), and extends toward the negative side in the X-axis direction and the positive side in the Y-axis direction. Terminal portion 7A is formed by widening a portion near the other end of the conductor portion 4A toward the positive side in the Y-axis direction, and bending the widened portion toward the negative side in the X-axis direction. Terminal portion 7B is connected to the other end of the conductor portion 4B of the first coil conductor 3A (i.e., the negative end in the Z-axis direction), and extends toward the negative side in the X-axis direction and the negative side in the Y-axis direction. The terminal portion 7B is formed by widening a portion of the conductor portion 4B near the other end towards the negative side in the Y-axis direction, and then bending this widened portion towards the negative side in the X-axis direction. The terminal portions 7A and 7B connected to the first coil conductor 3A extend to the first side surface 90a, passing through the lower surface 2f of the first magnetic block 2A adjacent to the first coil conductor 3A on the negative side in the X-axis direction, with the end portion 7a located on the negative side in the X-axis direction exposed from the first side surface 90a. As shown in Figure 4, the terminal portions 7A and 7B exposed on the first side surface 90a have a substantially rectangular shape extending along the Y-axis direction. The terminal portions 7A and 7B connected to the first coil conductor 3A and the first magnetic block 2A are spaced apart with respect to the Z-axis direction, and a gap G exists between the upper surface 7b of the terminal portions 7A and 7B (i.e., the positive side in the Z-axis direction) and the lower surface 2f of the magnetic block 2A, which face each other in the Z-axis direction. The terminal portions 7A and 7B connected to the first coil conductor 3A are joined to the land electrodes 102 of the substrate 101 on which the inductor 1 is mounted. This mounts the inductor 1 onto the substrate 101. As shown in Figure 3, the terminal portions 7A and 7B exposed on the first side surface 90a may protrude from the first side surface 90a.

[0024] The second coil conductor 3B, like the first coil conductor 3A, comprises a pair of conductor portions 4A and 4B and a connecting portion 6. A pair of terminal portions 7 are connected to the second coil conductor 3B. The pair of terminal portions 7 may be provided integrally with the second coil conductor 3B or as separate components. The pair of terminal portions 7 connected to the second coil conductor 3B correspond to the "second terminal portion" in the claims. The pair of terminal portions 7 consists of terminal portion 7A and terminal portion 7B. Terminal portion 7A extends from the other end of conductor portion 4A of the second coil conductor 3B toward the positive side in the X-axis direction and the positive side in the Y-axis direction, and terminal portion 7B extends from the other end of conductor portion 4B of the second coil conductor 3B toward the positive side in the X-axis direction and the negative side in the Y-axis direction. The terminal portions 7A and 7B connected to the second coil conductor 3B extend to the second side surface 90b, passing through the lower surface 2f of the third magnetic block 2C adjacent to the second coil conductor 3B on the positive side in the X-axis direction, with the end portion 7a located on the positive side in the X-axis direction exposed from the second side surface 90b. The terminal portions 7A and 7B exposed on the second side surface 90b have a substantially rectangular shape extending along the Y-axis direction. The terminal portions 7A and 7B connected to the second coil conductor 3B and the third magnetic block 2C are spaced apart in the Z-axis direction, and a gap G exists between the upper surface 7b of the terminal portions 7A and 7B (i.e., the positive side in the Z-axis direction) and the lower surface 2f of the magnetic block 2C, which face each other in the Z-axis direction. The terminal portions 7A and 7B connected to the second coil conductor 3B are also joined to the land electrode 102 of the substrate 101 on which the inductor 1 is mounted. As shown in Figure 3, the terminal portions 7A and 7B exposed on the second side surface 90b may protrude from the second side surface 90b.

[0025] The terminal portions 7A and 7B connected to the first coil conductor 3A and the terminal portions 7A and 7B connected to the second coil conductor 3B all have their negative Z-axis surfaces exposed from the base body 90, and these exposed portions are joined to the land electrode 102. In addition, a portion of the negative Z-axis surface of the terminal portions 7A and 7B connected to the first coil conductor 3A and the terminal portions 7A and 7B connected to the second coil conductor 3B, adjacent to the negative Z-axis surface, located on the negative Z-axis side, may also be exposed from the base body 90.

[0026] In this embodiment, the terminal portions 7A and 7B connected to the first coil conductor 3A and the terminal portions 7A and 7B connected to the second coil conductor 3B are all covered on their upper surfaces 7b with an insulating layer 8. The insulating layer 8 may cover the entire upper surface 7b of the terminal portions 7A and 7B, or it may cover only a portion of it. The insulating layer 8 may be composed of a material in which a filler is dispersed in an epoxy resin, for example. The peel strength at the interface between the insulating layer 8 and the base material may be set to be higher than the peel strength at the interface between the insulating layer 8 and the terminal portions 7A and 7B. By thermally curing the base material while the insulating layer 8 and the base material are in close contact, the peel strength at the interface between the insulating layer 8 and the base material can be increased. The deformation of the terminal portions 7A and 7B is suppressed by the base material being in close contact with the terminal portions 7A and 7B via the insulating layer 8.

[0027] An adhesive 9 is interposed between each of the magnetic blocks 2 and each of the coil conductors 3, and the two are bonded together by the adhesive 9. More specifically, the adhesive 9 is provided on the opposing surfaces 4Aa and 4Ab of the conductor portion 4A and the opposing surfaces 4Ba and 4Bb of the conductor portion 4B of each coil conductor 3. More specifically, the adhesive 9 is provided on each of the opposing regions R of the opposing surfaces 4Aa, 4Ab, 4Ba, and 4Bb that face the magnetic block 2. The adhesive 9 can be applied to the opposing regions R using known coating techniques such as nozzles. The adhesive 9 may be composed of a material in which a filler is dispersed in a resin. The filler may be a magnetic material or a non-magnetic material.

[0028] Next, we will describe the enclosure of the magnetic block 2 and coil conductor 3 by the base material constituting the base body 90.

[0029] The base material constituting the base body 90 integrally covers the three magnetic blocks 2A to 2C and the pair of coil conductors 3A and 3B. With respect to the first magnetic block 2A, all surface areas (i.e., the remaining area of ​​the opposing region R) except for the opposing region R between the first magnetic block 2A and the first coil conductor 3A (i.e., the region to which the adhesive 9 is applied) are covered with the base material. The base material is also provided in the gap G between the lower surface 2f of the first magnetic block 2A and the upper surface 7b of the terminal portions 7A and 7B connected to the first coil conductor 3A. Specifically, the gap G is substantially filled with the base material constituting the base body 90. Since the base material contains resin, voids may be accidentally generated when air is entrained during its flow, but even if such voids in the base material are located in the gap G, the gap G can be considered to be filled with the base material constituting the base body 90. The thickness of the gap G (i.e., the length in the Z-axis direction) substantially coincides with the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G. The thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A may be greater than or equal to the thickness of the terminal portions 7A and 7B connected to the first coil conductor 3A. If the adhesive 9 is partially applied to the opposing region R between the first magnetic block 2A and the first coil conductor 3A, the main surface 2b of the first magnetic block 2A that is not covered by the adhesive 9 within the opposing region R will be included in the remaining region of the opposing region R.

[0030] The base material covers the entire main surface 2a of the first magnetic block 2A facing the first side surface 90a of the base body 90. The thickness T2 of the base material covering the main surface 2a of the first magnetic block 2A may be the same as or different from the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G. In this embodiment, the thickness T2 of the base material covering the main surface 2a of the first magnetic block 2A is designed to be thicker than the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G (T2 > T1). The base material covers the entire upper surface 2e of the first magnetic block 2A facing the upper surface 90e of the base body 90. The thickness T3 of the base material covering the upper surface 2e of the first magnetic block 2A may be the same as or different from the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G. In this embodiment, the thickness T3 of the base material covering the upper surface 2e of the first magnetic block 2A is designed to be thicker than the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G (T3 > T1). In this embodiment, among the surfaces 2a to 2f of the first magnetic block 2A covered with base material, the thickness of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G is the thinnest, and the thickness of the base material on surfaces other than the lower surface 2f in the gap G is thicker than the thickness T1 of the base material covering the lower surface 2f in the gap G. Furthermore, the thickness of the base material covering the surface of the lower surface 2f of the first magnetic block 2A other than the gap G (i.e., the remaining region of the area facing the terminal portions 7A and 7B on the lower surface 2f of the first magnetic block 2A) is thicker than the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G.

[0031] With respect to the third magnetic block 2C, all surface areas (i.e., the remaining area of ​​the opposing region R) of the third magnetic block 2C and the second coil conductor 3B, except for the opposing region R (i.e., the region to which the adhesive 9 is applied), are covered with the base material. The base material is also provided in the gap G between the lower surface 2f of the third magnetic block 2C and the upper surfaces 7b of the terminal portions 7A and 7B connected to the second coil conductor 3B. Specifically, the gap G is substantially filled with the base material constituting the base body 90. The thickness of the gap G (i.e., the length in the Z-axis direction) substantially coincides with the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G. The base material covers the entire main surface 2b of the third magnetic block 2C facing the second side surface 90b of the base body 90. The thickness T5 of the base material covering the main surface 2b of the third magnetic block 2C may be the same as or different from the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G. In this embodiment, the thickness T5 of the base material covering the main surface 2b of the third magnetic block 2C is designed to be thicker than the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G (T5 > T4). The base material covers the entire upper surface 2e of the third magnetic block 2C facing the upper surface 90e of the base material 90. The thickness T6 of the base material covering the upper surface 2e of the third magnetic block 2C may be the same as or different from the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G. In this embodiment, the thickness T6 of the base material covering the upper surface 2e of the third magnetic block 2C is designed to be thicker than the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G (T6 > T4). In this embodiment, among the surfaces 2a to 2f of the third magnetic block 2C covered with base material, the thickness of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G is the thinnest, and the thickness of the base material on the surfaces other than the lower surface 2f in the gap G is thicker than the thickness T4 of the base material covering the lower surface 2f in the gap G.Furthermore, the thickness of the base material covering the surface of the lower surface 2f of the third magnetic block 2C other than the gap G (i.e., the remaining region of the area facing the terminal portions 7A and 7B on the lower surface 2f of the third magnetic block 2C) is greater than the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G.

[0032] In the gap G, the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C may be the same as or different from the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G. In this embodiment, the thickness T4 of the base material covering the lower surface 2f of the third magnetic block 2C in the gap G is the same as the thickness T1 of the base material covering the lower surface 2f of the first magnetic block 2A in the gap G, and since the length of the first magnetic block 2A in the Z-axis direction and the length of the third magnetic block 2C in the Z-axis direction are the same, the first magnetic block 2A and the third magnetic block 2C are in the same position in the Z-axis direction. In this embodiment, the length of the second magnetic block 2B in the Z-axis direction is the same as the length of the first magnetic block 2A and the third magnetic block 2C in the Z-axis direction, but the second magnetic block 2B is in a different position in the Z-axis direction from the first magnetic block 2A and the third magnetic block 2C, specifically on the lower surface 90f side. In this embodiment, the second magnetic block 2B is located on the lower surface 90f side of the base body 90 than the first magnetic block 2A and the third magnetic block 2C. However, the lower surface 2f of the second magnetic block 2B is located on the upper surface 90e side of the base body 90 than the upper surface 7b of the magnetic block 2 of the terminal portions 7A and 7B that faces the lower surface 2f of the magnetic block 2, in the Z-axis direction. That is, the upper surface 2e of the first magnetic block 2A is located on the upper surface 90e side of the base body 90 than the upper surface 2e of the second magnetic block 2B, and the lower surface 2f of the second magnetic block 2B is located on the lower surface 90f side of the base body 90 than the lower surface 2f of the first magnetic block 2A. Also, the upper surface 2e of the third magnetic block 2C is located on the upper surface 90e side of the base body 90 than the upper surface 2e of the second magnetic block 2B, and the lower surface 2f of the second magnetic block 2B is located on the lower surface 90f side of the base body 90 than the lower surface 2f of the third magnetic block 2C. The thickness T5 of the base material covering the main surface 2b of the third magnetic block 2C may be the same as or different from the thickness T2 of the base material covering the main surface 2a of the first magnetic block 2A. The thickness T6 of the base material covering the top surface 2e of the third magnetic block 2C may be the same as or different from the thickness T3 of the base material covering the top surface 2e of the first magnetic block 2A.

[0033] With respect to the second magnetic block 2B, all surfaces 2a to 2f are covered with the base material, except for the region R (i.e., the region to which the adhesive 9 is applied) that faces the second magnetic block 2B and the first coil conductor 3A and the second coil conductor 3B.

[0034] In inductor 1, since a base material is interposed in the gap G between the lower surface 2f of the magnetic block 2 and the upper surface 7b of the terminal portions 7A and 7B, the magnetic block 2 is not directly resting on the terminal portions 7A and 7B, and the lower surface 2f of the magnetic block 2 is not in direct contact with the upper surface 7b of the terminal portions 7A and 7B.

[0035] As shown in Figure 5, in a configuration where a magnetic block 202 similar to the magnetic block 2A described above is directly mounted on a terminal portion 207 similar to the terminal portion 7A described above, when the magnetic block 202 undergoes thermal expansion in the Z-axis direction under high-temperature conditions, the magnetic block 202 presses the terminal portion 207 downward (i.e., to the negative side in the Z-axis direction). If the magnetic block 202 is a laminated magnetic core stacked in the Z-axis direction, it is particularly prone to stretching in the Z-axis direction. For example, during reflow soldering when mounting an inductor to a substrate, the inductor is placed in a high-temperature environment of around 260 degrees Celsius. At this time, a force is applied to the terminal portion 207 in a direction that causes it to peel away from the base body 90, resulting in relatively large internal stress in the base body 90 near the interface between the magnetic block 202 and the terminal portion 207, and a crack 92 extending from the interface between the magnetic block 202 and the terminal portion 207 may occur in the base body 90. If the crack 92 appears on the first side surface 90a of the base body 90, it will be observed on the first side surface 90a. Crack 92 may also appear on the third side 90c (or fourth side 90d) of the base body 90.

[0036] In an inductor 1 in which a base material is interposed in the gap G between the lower surface 2f of the magnetic block 2 and the upper surfaces 7b of the terminal portions 7A and 7B, the magnetic block 2 does not rest directly on the terminal portions 7A and 7B. Therefore, when the magnetic block 2 undergoes thermal expansion in the Z-axis direction under high-temperature conditions, the magnetic block 2 does not directly press down on the terminal portions 7A and 7B. This suppresses the occurrence of the aforementioned cracks 92 in the base material 90. In fact, the thermal expansion on the lower surface 2f of the magnetic block 2 is suppressed to some extent by the base material located in the gap G. As a result, the internal stress generated in the base material 90 near the interface between the magnetic block 2 and the terminal portions 7A and 7B is suppressed, further suppressing the occurrence of cracks 92 caused by internal stress.

[0037] Next, the operation and effects of the inductor 1 according to this embodiment will be explained.

[0038] The inductor 1 comprises a base body 90 made of a base material including resin, a magnetic block 2 provided inside the base body 90, a coil conductor 3 provided inside the base body 90, and terminal portions 7A and 7B extending from the ends of the conductor portions 4A and 4B of the coil conductor 3 on the lower surface 90f side toward the first side surface 90a of the base body 90 and facing the lower surface 2f of the magnetic block 2. The gap G between the lower surface 2f of the magnetic block 2 and the terminal portions 7A and 7B is filled with the base material that constitutes the base body 90. Therefore, in a high-temperature environment where the magnetic block 2 undergoes thermal expansion in the Z-axis direction, the magnetic block 2 does not directly press the terminal portions 7A and 7B downward, and the occurrence of the aforementioned cracks 92 in the base body 90 is suppressed.

[0039] The base material does not cover the opposing region R of the magnetic block 2's surface that faces the coil conductor 3, but covers the remaining region of the opposing region R. In this way, by covering most of the surface area of ​​the magnetic block 2 with the base material, the thermal expansion of the magnetic block 2 is effectively suppressed, and the occurrence of cracks in the base material 90 caused by the thermal expansion of the magnetic block 2 is suppressed.

[0040] The thickness T1 of the base material in the gap G may be equal to or greater than the thickness T2 of the base material covering the main surface 2a of the magnetic block 2 (T1≧T2). In this case, the gap G is filled with the base material of sufficient thickness, so that the occurrence of cracks 92 is more reliably suppressed.

[0041] The thickness T1 of the base material in the gap G may be smaller than the thickness T2 of the base material covering the main surface 2a of the magnetic block 2 (T1<T2). In this case, high strength can be ensured on the first side surface 90a side of the base body 90, and the occurrence of cracks on the first side surface 90a of the base body 90 is suppressed.

[0042] When the thickness T1 of the base material in the gap G is equal to or greater than the thickness t of the terminal portions 7A, 7B and equal to or less than the thickness T3 of the base material covering the upper surface 2e of the magnetic block 2, the gap G is filled with the base material of sufficient thickness, so that the occurrence of cracks 92 can be more reliably suppressed, and the product size of the inductor 1 is prevented from being unnecessarily increased.

[0043] When the thickness of the base material covering the remaining region of the facing region R facing the coil conductor 3 in the surface region of the magnetic block 2 is greater than the thickness T1 of the base material in the gap G, the base body 90 with high strength can be realized.

[0044] In the inductor 1, the coil conductor 3 includes a pair of conductor portions 4A, 4B and a connection conductor portion 6, and a pair of terminal portions 7A, 7B extend from respective end portions on the lower surface 90f side of the conductor portions 4A, 4B of the coil conductor 3. Therefore, two terminals can be formed on the lower surface 90f of the base body 90.

[0045] The upper surface 2e of the magnetic block 2 is located on the lower surface 90f side of the surface on the lower surface 90f side of the connecting conductor portion 6. In this case, the magnetic block 2 is less likely to obstruct the magnetic flux around the connecting conductor portion 6, thus improving the inductance. Furthermore, when molding the base body 90 using a paste-like base material, the magnetic block 2 is less likely to obstruct the flow of the base material into the space defined by the conductor portions 4A and 4B of the coil conductor 3 and the connecting conductor portion 6, allowing the space to be filled with the base material more reliably.

[0046] In the inductor 1, in addition to the first magnetic block 2A, a second magnetic block 2B is provided within the base body 90 so as to sandwich the first coil conductor 3A between the first magnetic block 2A and the second magnetic block 2B, thereby further improving the inductance.

[0047] The lower surface 2f of the second magnetic block 2B may be located on the upper surface 90e side of the upper surface 7b of the terminal portions 7A and 7B.

[0048] The upper surface 2e of the second magnetic block 2B may also be located on the lower surface 90f side of the lower surface 90f side of the connecting conductor portion 6 of the first coil conductor 3A, similar to the upper surface 2e of the first magnetic block 2A. In this case, the second magnetic block 2B is less likely to obstruct the magnetic flux around the connecting conductor portion 6 of the first coil conductor 3A, thus improving the inductance. Furthermore, when molding the base body 90 using a paste-like base material, the second magnetic block 2B is less likely to obstruct the flow of the base material into the space defined by the conductor portions 4A and 4B of the first coil conductor 3A and the connecting conductor portion 6, allowing the space to be filled with the base material more reliably.

[0049] The upper surface 2e of the first magnetic block 2A may be located on the upper surface 90e side of the upper surface 2e of the second magnetic block 2B, and the lower surface 2f of the second magnetic block 2B may be located on the lower surface 90f side of the lower surface 2f of the first magnetic block 2A. With respect to the length (height) in the Z-axis direction, if the length of the first magnetic block 2A and the length of the second magnetic block 2B are the same or approximately the same, the first magnetic block 2A may be shifted toward the upper surface 90e side relative to the second magnetic block 2B.

[0050] An insulating layer 8 is interposed between the upper surface 7b of the terminal portions 7A and 7B and the base material filling the gap G. The insulating layer 8 prevents solder from spreading to the upper surface 7b of the terminal portions 7A and 7B during reflow soldering.

[0051] The peel strength at the interface between the insulating layer 8 and the base material may be higher than the peel strength at the interface between the insulating layer 8 and the terminal portions 7A and 7B. In this case, the terminal portions 7A and 7B are more easily fixed by the base material, and the strength is improved.

[0052] The base material constituting the base body 90 of inductor 1 is a magnetic resin containing magnetic materials such as soft magnetic metal powder, thus improving the inductance compared to base materials that do not contain magnetic materials. In this case, the permeability of the magnetic block 2 may be higher than that of the base material.

[0053] The thermal expansion coefficient of magnetic block 2 in the Z-axis direction is greater than the thermal expansion coefficients in the X-axis and Y-axis directions. In this case, the gap G that overlaps magnetic block 2 in the Z-axis direction is filled with the base material, which effectively suppresses cracks 92 caused by thermal expansion of magnetic block 2 in the Z-axis direction.

[0054] The inductor 1 includes a second coil conductor 3B provided within the base body 90 and sandwiching a second magnetic block 2B between it and a first coil conductor 3A in the X-axis direction, a third magnetic block 2C provided within the base body 90 and sandwiching the second coil conductor 3B between it and the second magnetic block 2B in the X-axis direction, and terminal portions 7A and 7B extending from the ends of the conductor portions 4A and 4B of the second coil conductor 3B on the lower surface 90f side toward the second side surface 90b of the base body 90 and facing the lower surface 2f of the third magnetic block 2C, with the gap G between the lower surface 2f of the third magnetic block 2C and the terminal portions 7A and 7B being filled with the base material constituting the base body 90. Therefore, under conditions where the third magnetic block 2C undergoes thermal expansion in the Z-axis direction in a high-temperature environment, the third magnetic block 2C does not directly press downwards against the terminal portions 7A and 7B of the second coil conductor 3B, thereby suppressing the occurrence of the aforementioned crack 92 in the base body 90.

[0055] The upper surface 2e of the third magnetic block 2C may be located on the upper surface 90e side of the upper surface 2e of the second magnetic block 2B, and the lower surface 2f of the second magnetic block 2B may be located on the lower surface 90f side of the lower surface 2f of the third magnetic block 2C. With respect to the length (height) in the Z-axis direction, if the length of the third magnetic block 2C and the length of the second magnetic block 2B are the same or approximately the same, the third magnetic block 2C may be shifted toward the upper surface 90e side relative to the second magnetic block 2B.

[0056] Furthermore, the third magnetic block 2C does not necessarily need to be shifted toward the upper surface 90e side relative to the second magnetic block 2B. Similarly, the first magnetic block 2A does not necessarily need to be shifted toward the upper surface 90e side relative to the second magnetic block 2B. For example, as shown in Figure 6, the first magnetic block 2A, the second magnetic block 2B, and the third magnetic block 2C may be in the same position with respect to the Z-axis direction. In this case, magnetic blocks 2A to 2C may be arranged in the same position in the YZ plane such that their end faces and sides overlap each other when viewed from the X-axis direction. Positional deviations within a range that occur due to manufacturing tolerances, etc., are included in "same position".

[0057] This disclosure is not limited to the embodiments described above. Although the inductor according to the embodiments described above includes two coil conductors, the number of coil conductors is not particularly limited and may be one or three or more. Also, although the inductor according to the embodiments described above includes three magnetic blocks, the number of magnetic blocks 2 may be one, two, or four or more.

[0058] As can be seen from the above description, this specification discloses the following: [Note 1] A body having a first side surface and a second side surface facing each other in a first direction, and a first main surface and a second main surface facing each other in a second direction perpendicular to the first direction, and composed of a base material containing resin, A first magnetic body provided within the aforementioned body, having a first surface facing the first side and a second surface facing the second side, a third surface facing the first main surface and a fourth surface facing the second main surface, A first coil conductor is provided within the aforementioned body, and at least a portion of it faces the second surface of the first magnetic material, A first terminal portion extends from the end of the first main surface side of the first coil conductor toward the first side surface and faces the third surface of the first magnetic material, and at least a portion of it is exposed from the first main surface of the base material. Equipped with, An inductor in which the gap between the third surface of the first magnetic material and the first terminal portion is filled with the base material. [Note 2] The inductor according to Appendix 1, wherein the base material covers the remaining region of the second surface of the surface region of the first magnetic material that faces the first coil conductor. [Note 3] The inductor according to Appendix 2, wherein the length of the base material in the second direction in the gap between the third surface of the first magnetic material and the first terminal portion is greater than or equal to the length of the base material covering the first surface of the first magnetic material in the first direction. [Note 4] The inductor according to Appendix 2 or 3, wherein the length of the base material in the second direction in the gap between the third surface of the first magnetic material and the first terminal portion is shorter than the length of the base material covering the first surface of the first magnetic material in the first direction. [Note 5] An inductor according to any one of the appendices 2 to 4, wherein the length of the base material in the gap between the third surface of the first magnetic material and the first terminal portion in the second direction is greater than or equal to the length of the first terminal portion in the second direction, and less than or equal to the length of the base material covering the fourth surface of the first magnetic material in the second direction. [Note 6] An inductor according to any one of the appendices 2 to 5, wherein the thickness of the base material covering the remaining region of the third surface of the first magnetic material that faces the first terminal portion is greater than the thickness of the base material covering the region of the third surface of the first magnetic material that faces the first terminal portion. [Note 7] The first coil conductor includes a first conductor portion and a second conductor portion that extend in the second direction and face the second surface of the first magnetic material, and a connecting conductor portion that connects the first conductor portion and the second conductor portion. An inductor according to any one of the appendices 1 to 6, wherein a pair of first terminal portions extend from the respective ends on the first main surface side of the first conductor portion and the second conductor portion of the first coil conductor. [Note 8] The inductor according to Appendix 7, wherein the fourth surface of the first magnetic material is located on the first main surface side of the connecting conductor portion. [Note 9] The substrate further comprises a second magnetic material provided within the substrate, which sandwiches the first coil conductor between itself and the first magnetic material in the first direction, The second magnetic material has a first surface facing the first side and a second surface facing the second side, and a third surface facing the first main surface and a fourth surface facing the second main surface, The inductor according to appendix 7 or 8, wherein the first conductor portion and the second conductor portion of the first coil conductor face the first surface of the second magnetic material. [Note 10] The inductor according to Appendix 9, wherein the third surface of the second magnetic material is located on the second main surface side of the opposing surface of the first terminal portion that faces the first magnetic material in the second direction. [Note 11] The inductor according to appendix 9 or 10, wherein the fourth surface of the second magnetic material is located on the first main surface side of the connecting conductor portion. [Note 12] An inductor according to any one of appendices 9 to 11, wherein the fourth surface of the first magnetic material is located on the second main surface side of the fourth surface of the second magnetic material, and the third surface of the second magnetic material is located on the first main surface side of the third surface of the first magnetic material. [Note 13] An inductor according to any one of the appendices 1 to 12, wherein an insulating layer is interposed between the opposing surface of the first terminal portion facing the first magnetic material in the second direction and the base material. [Note 14] The inductor according to Appendix 13, wherein the peel strength at the interface between the insulating layer and the base material is higher than the peel strength at the interface between the insulating layer and the first terminal portion. [Note 15] The inductor according to any one of the appendices 1 to 14, wherein the aforementioned base material is a magnetic resin containing a magnetic material. [Note 16] The inductor described in Appendix 15, wherein the permeability of the first magnetic material is higher than the permeability of the magnetic resin. [Note 17] An inductor according to any one of the appendices 1 to 16, wherein the coefficient of thermal expansion of the first magnetic material in the second direction is greater than the coefficient of thermal expansion in the first direction and in a third direction perpendicular to the first and second directions. [Note 18] A second coil conductor is provided within the body, and in the first direction, it sandwiches the second magnetic material between itself and the first coil conductor, with at least a portion of it facing the second surface of the second magnetic material. A third magnetic material is provided within the aforementioned body, and in the first direction, the second coil conductor is sandwiched between it and the second magnetic material, and the third magnetic material has a first surface facing the first side and a second surface facing the second side, and a third surface facing the first main surface and a fourth surface facing the second main surface, A second terminal portion extends from the end of the second coil conductor on the first main surface side to the second side surface side, facing the third surface of the third magnetic material, and at least a portion of which is exposed from the first main surface of the base material. Furthermore, The inductor according to Appendix 9, wherein the gap between the third surface of the third magnetic material and the second terminal portion is filled with the base material. [Note 19] The inductor according to Appendix 18, wherein the fourth surface of the third magnetic material is located on the second main surface side of the fourth surface of the second magnetic material, and the third surface of the second magnetic material is located on the first main surface side of the third surface of the third magnetic material. [Note 20] A DC-DC converter equipped with an inductor described in any one of the appendices 1 to 19. [Explanation of Symbols]

[0059] 1...Inductor, 2...Magnetic block, 3...Coil conductor, 4A, 4B...Conductor part, 6...Connecting conductor part, 7A, 7B...Terminal part, 90...Element, 500...DC-DC converter, G...Gap.

Claims

1. A base body having a first side surface and a second side surface facing each other in a first direction, and a first main surface and a second main surface facing each other in a second direction perpendicular to the first direction, and composed of a base material containing resin, A first magnetic body provided within the aforementioned body, having a first surface facing the first side and a second surface facing the second side, a third surface facing the first main surface and a fourth surface facing the second main surface, A first coil conductor is provided within the aforementioned body, and at least a portion of it faces the second surface of the first magnetic material, A first terminal portion extends from the end of the first main surface side of the first coil conductor toward the first side surface and faces the third surface of the first magnetic material, and at least a part of it is exposed from the first main surface of the base material. Equipped with, An inductor in which the gap between the third surface of the first magnetic material and the first terminal portion is filled with the base material.

2. The inductor according to claim 1, wherein the substrate material covers the remaining region of the second surface of the surface region of the first magnetic material that faces the first coil conductor.

3. The inductor according to claim 2, wherein the length of the base material in the second direction in the gap between the third surface of the first magnetic material and the first terminal portion is greater than or equal to the length of the base material covering the first surface of the first magnetic material in the first direction.

4. The inductor according to claim 2, wherein the length of the base material in the second direction in the gap between the third surface of the first magnetic material and the first terminal portion is shorter than the length of the base material covering the first surface of the first magnetic material in the first direction.

5. The inductor according to claim 2, wherein the length of the base material in the gap between the third surface of the first magnetic material and the first terminal portion in the second direction is greater than or equal to the length of the first terminal portion in the second direction, and less than or equal to the length of the base material covering the fourth surface of the first magnetic material in the second direction.

6. The inductor according to claim 2, wherein the thickness of the base material covering the remaining region of the third surface of the first magnetic material that faces the first terminal portion is greater than the thickness of the base material covering the region of the third surface of the first magnetic material that faces the first terminal portion.

7. The first coil conductor includes a first conductor portion and a second conductor portion that extend in the second direction and face the second surface of the first magnetic material, and a connecting conductor portion that connects the first conductor portion and the second conductor portion. The inductor according to claim 1, wherein a pair of first terminal portions extend from the respective ends on the first main surface side of the first conductor portion and the second conductor portion of the first coil conductor.

8. The inductor according to claim 7, wherein the fourth surface of the first magnetic material is located on the first main surface side of the connecting conductor portion.

9. The substrate further comprises a second magnetic material provided within the substrate, which sandwiches the first coil conductor between itself and the first magnetic material in the first direction, The second magnetic material has a first surface facing the first side and a second surface facing the second side, and a third surface facing the first main surface and a fourth surface facing the second main surface, The inductor according to claim 7, wherein the first conductor portion and the second conductor portion of the first coil conductor face the first surface of the second magnetic material.

10. The inductor according to claim 9, wherein the third surface of the second magnetic material is located on the second main surface side of the opposing surface of the first terminal portion that faces the first magnetic material in the second direction.

11. The inductor according to claim 9, wherein the fourth surface of the second magnetic material is located on the first main surface side of the connecting conductor portion.

12. The inductor according to claim 9, wherein the fourth surface of the first magnetic material is located on the second main surface side of the fourth surface of the second magnetic material, and the third surface of the second magnetic material is located on the first main surface side of the third surface of the first magnetic material.

13. The inductor according to claim 1, wherein an insulating layer is interposed between the opposing surface of the first terminal portion facing the first magnetic material in the second direction and the base material.

14. The inductor according to claim 13, wherein the peel strength at the interface between the insulating layer and the base material is higher than the peel strength at the interface between the insulating layer and the first terminal portion.

15. The inductor according to claim 1, wherein the base material is a magnetic resin containing a magnetic material.

16. The inductor according to claim 15, wherein the permeability of the first magnetic material is higher than the permeability of the magnetic resin.

17. The inductor according to claim 1, wherein the coefficient of thermal expansion of the first magnetic material in the second direction is greater than the coefficient of thermal expansion in the first direction and in a third direction perpendicular to the first and second directions.

18. A second coil conductor is provided within the aforementioned body, and in the first direction, it sandwiches the second magnetic material between itself and the first coil conductor, with at least a portion of it facing the second surface of the second magnetic material, A third magnetic material is provided within the aforementioned body, and in the first direction, the second coil conductor is sandwiched between it and the second magnetic material, and the third magnetic material has a first surface facing the first side and a second surface facing the second side, and a third surface facing the first main surface and a fourth surface facing the second main surface, A second terminal portion extends from the end of the second coil conductor on the first main surface side toward the second side surface and faces the third surface of the third magnetic material, and at least a part of it is exposed from the first main surface of the base material. Furthermore, The inductor according to claim 9, wherein the gap between the third surface of the third magnetic material and the second terminal portion is filled with the base material.

19. The inductor according to claim 18, wherein the fourth surface of the third magnetic material is located on the second main surface side of the fourth surface of the second magnetic material, and the third surface of the second magnetic material is located on the first main surface side of the third surface of the third magnetic material.

20. A DC-DC converter comprising an inductor according to any one of claims 1 to 19.

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