CN110648817A - Inductor subassembly - Google Patents

Abstract

An inductor assembly includes a plurality of inductor regions having winding densities of wires different from each other are arranged in a longitudinal direction of a core when a winding density represents a number of turns of the wires per unit length in the longitudinal direction of the core, and a low-density inductor and a region where the winding density is relatively low are located between first and second high densities, and the inductance region and the winding density are relatively high.

Description

Inductor subassembly

Technical Field

The invention relates to the technical field of inductor assemblies, in particular to a wire-wound inductor assembly with a structure, wherein a conducting wire is wound on a core part of a core.

Background

For example, as described in japanese unexamined patent application publication No.2004-363178, the wound-wire inductor component has a structure in which a winding wire is wound on a core portion of a core made of a magnetic material. Also, the inductor assembly described in japanese unexamined patent application publication No.2004-363178 basically has an inductor for the core.

An equivalent circuit of the wound inductor component is shown in fig. 2. 5. As shown in fig. 2. As shown in fig. 5, the equivalent circuit of the inductor component has an inductance L originally provided as a basic element and a capacitance C derived from a distributed capacitance (stray capacitance) or the like generated between the windings, and is added in parallel with the capacitance C. The equivalent circuit of the inductance L actually comprises a series/parallel resistance. However, this resistance is not shown in fig. 1.

Such inductor assemblies with large values of inductance L typically have large values of equivalent parallel capacitance C, which is the above-mentioned distributed capacitance. That is, the case where the inductance L value is large indicates that the extended length of the wire is large, and the case where the equivalent parallel capacitance C value also indicates that the parallel length of the capacitor electrode is long. The opposing area of the capacitor electrodes is large. Therefore, the equivalent parallel capacitance C value becomes large. Therefore, in the inductor component having a large inductance L value, the low-frequency impedance becomes high and the high-frequency impedance becomes low. In other words, the inductor assembly having good low frequency characteristics has poor high frequency characteristics.

If good characteristics are required over a wide frequency band, there may be a method of preparing an inductor assembly having a large L value and an inductor assembly having a low L value, and connecting the inductor assemblies in series, thereby fully extending the frequency band.

For example, japanese unexamined patent application publication No. 2010-232988 describes a broadband bias circuit having one end connected to a power supply and the other end connected to an amplification circuit that amplifies a broadband high-frequency signal using a predetermined signal. Frequency bands. The broadband bias circuit provides a dc bias current. The broadband bias circuit includes at least three stages of inductors connected in series with respect to at least one of a node of an input side and a node of an output side of the amplifier circuit. Paragraphs 0005 and 0008 of japanese unexamined patent application publication No.2004-363178 describe that at least three stages of multi-stage inductors can conform to a broadband signal. In addition, paragraphs 0034 and 0044 of japanese unexamined patent application publication.

Fig. 6 is a plan view schematically showing a state in which three chip inductors 1 to 3 as inductor components are connected in series via lands 4 and 5 and mounted on a branch portion between a high-frequency line 6 and a low-frequency line. Fig. 7 shows the method shown in fig. 7 according to the technique described in japanese unexamined patent application publication No. 2004-363178.

For example, a high-frequency signal having a frequency of several gigahertz or more flows through the high-frequency line 6. On the other hand, a low-frequency (or direct-current) current such as a power supply current flows through the low-frequency line 7. The chip inductors 1 to 3 serve to suppress the high frequency signal from entering the low frequency line 7 and suppress the low frequency (or direct current) current from entering the high frequency line 6.

If chip inductor 3 three chip inductors 1 to 3 have the smallest L value, chip inductors 1 and 2 have larger L values, and the smaller L value 2 of the chip inductor is smaller than L value of the chip inductor 1, the chip inductor 3 having the smallest L value is closest to the high frequency line 6, and chip inductor 2 and chip inductor 1 are connected in series in this order. Since a high-frequency signal flows through the high-frequency line 6, if an inductor that does not conform to a high frequency, that is, the chip inductor 1 having a large L value, approaches the high-frequency signal, unexpected results such as degradation in isolation may be caused. Therefore, the above structure is considered reasonable.

Disclosure of Invention

Fig. 7 shows impedance-frequency characteristics of the above chip inductors 1 to 3. The L value of the chip inductor 1 is 47 μ H, the L value of the chip inductor 2 is 10 μ H, and the L value of the chip inductor 3 is 3.5 μ H, the L value for the characteristic measurement shown in fig. 1. 7. In fig. 7, a represents the impedance-frequency characteristic of one inductor 1, and B represents the impedance-frequency characteristic of one inductor 2. C is an impedance-frequency characteristic of one chip inductor 3, and D is an impedance-frequency characteristic when the chip inductors 1 to 3 are connected in series.

As described above, even if the chip inductors 1 to 3 are connected in series to obtain good characteristics on the line, it is found that impedance drop occurs between the resonance frequencies as shown by D in fig. 2. 7.

As described above, as shown in fig. 1, it is difficult to obtain good characteristics over a wide band. Fig. 7 is fig. 6 having the configuration of the related art shown in fig. 6.

It is therefore an object of the present disclosure to provide an inductor assembly with a new configuration that can ensure a high impedance over a wide band.

It is another object of the present disclosure to provide an inductor assembly in which a plurality of inductors connected in series are integrated into one chip.

According to one embodiment of the present disclosure, an inductor assembly comprises: a core including a core portion extending in a longitudinal direction; and at least one wire helically wound on the core; and a pair of terminal electrodes electrically connected to respective ends of the lead wires.

In the above inductor assembly, when the winding density indicates the number of turns of the wire per unit length in the longitudinal direction of the core, a plurality of inductor regions having different winding densities of the wire from each other are arranged in the longitudinal direction of the wire. Further, between the first and second high-density inductor regions having a relatively high winding density, a low-density inductor region having a relatively low winding density is provided.

With the inductor assembly according to embodiments of the present disclosure, multiple inductors are formed for a single core.

In some embodiments of the present disclosure, the length of the first high-density inductor region in the longitudinal direction of the core may be different from or may be the same as the length of the second high-density inductor region in the longitudinal direction of the second portion.

Also, in some embodiments of the present disclosure, the winding density in the first high-density inductor region may be different from or may be the same as the winding density in the second high-density inductor region.

In some embodiments of the present disclosure, the low-density inductor region located between the first high-density inductor region and the second high-density inductor region may be located at a central portion in the longitudinal direction of the core. With this configuration, the low-density inductor region can be reasonably located between the first high-density inductor region and the second high-density inductor region, and the directivity of the inductor components unified into one chip can be almost eliminated.

In some embodiments of the present disclosure, the wire may be wound in a single layer in the low density inductor region and may be wound in multiple layers in the high density inductor region. With this configuration, the winding density of the wire can be easily changed by selecting between the single-layer winding and the multi-layer winding. Also, even if the wire is wound so that the wire in one turn is in contact with the wire in another turn adjacent to the other turn, the winding density of the wire can be changed by selecting between the single-layer winding and the multi-layer winding. Therefore, the position of the wire is less likely to move on the core, and variations in inductance values due to unexpected changes in winding density of the wire can be reduced.

In some embodiments of the present disclosure, the wire may include a single wire connected between a pair of terminal electrodes, the single wire may be wound in a single layer in the low density inductor region, and the single wire may be wound in a plurality of wires. A metal layer in the high-density inductor region. Alternatively, the conductive wire may include a plurality of conductive wires connected between a pair of terminal electrodes, the plurality of conductive wires may be sequentially wound in a single layer in the low-density inductor region, and the plurality of conductive wires may be wound in the low-density inductor region.

As described above, if a plurality of wires are connected between a pair of terminal electrodes, the (direct current) resistance value of the inductor component can be reduced.

In some embodiments of the present disclosure, the core may be a drum-shaped core made of a magnetic material and including a pair of flange portions provided at respective ends of the core portion. Also, the inductor component may further include a plate-like core made of a magnetic material and bridging the pair of flange portions. With this configuration, the inductance value of the inductor component can be increased.

With the present disclosure, the inductor component has a new configuration in which a plurality of inductors are unified into one chip, and as clarified by the description of the embodiment, it is possible to ensure high impedance over a wide frequency band (described later).

Other features, elements, features and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a cross-sectional view schematically showing an inductor component according to a first embodiment of the present disclosure;

fig. 2 is a sectional view schematically showing an inductor assembly as a comparative example of the inductor assembly shown in fig. 1;

fig. 3 shows a comparison of impedance versus frequency characteristics between the inductor assemblies shown in fig. 2. The inductor assembly shown in fig. 1 and the inductor assembly shown in fig. 2 are shown;

fig. 4 is a cross-sectional view schematically illustrating an inductor component according to a second embodiment of the present disclosure;

fig. 5 is an equivalent circuit diagram of a wound inductor assembly for describing the related art of the present disclosure;

fig. 6 is a plan view schematically showing a state in which three chip inductors as inductor components are connected in series via lands and mounted on a branch portion between a high-frequency line and a low-frequency line;

fig. 7 shows impedance-frequency characteristics of the chip inductor shown in fig. 6.

Detailed Description

As shown in fig. 1, the inductor component 21 includes a drum core 13, the drum core 13 having a core portion 12 extending in a longitudinal direction. The drum core includes a pair of flange portions 14 and 15 provided at respective ends of the core portion 12. The inductor component 11 includes a slab core 16 bridging a pair of flange portions 14 and 15. The drum core 13 and the plate core 16 are made of a magnetic material such as ferrite, and form a closed magnetic circuit.

The wire 17 is spirally wound on the core 12. The winding form of the wire 17 will be described in detail later. The first and second flange portions 14 and 15 are provided with first and second terminal electrodes 18 and 19, respectively. Although not shown in fig. 1. As shown in fig. 1, respective ends of the wire 17 are electrically connected to the first terminal electrode 18 and the second terminal electrode 19.

As shown in fig. 1, the sequential number of turns "1" to "30" from the first flange portion 14 side is recorded in the cross section of the electric wire 17. The ordered number of turns written in the cross section of the wire 17 is also used in fig. 1 and 2. 2 and 4 (described later).

The winding form of the wire 17 on the core 12 is as follows. When the winding density indicates the number of turns of the wire 17 per unit length in the longitudinal direction of the core 12, three inductor regions L1 to L3 in which the winding densities of the wire 17 are different from each other are arranged in the longitudinal direction of the wire 17. A core 12. More specifically, the first high-density inductor region L1 and the second high-density inductor region L2 are in fig. 2, the winding density of the electric wire 17 is high because it is wound in multiple layers, for example, two layers. In fig. 1, a low-density inductor region L3 is provided in the center portion of the core 12 in fig. 1, and the winding density of the low-density inductor region L3 is low because the electric wire 17 is wound in a single layer. 1.

In other words, according to the present embodiment, the low-density inductor region L3 is located between the first and second high-density inductor regions L1 and L2.

As described above, since 1 and L2, in which the low-density inductance region L3 is located between the first and second high-density inductor regions on L, are positioned at the center portion 12 in the longitudinal direction of the core, the low-density inductance region L3 can be reasonably located between the first and second high-density inductance regions L by 1 and L2, and further, the directivity 11 of the inductor element is unified into one chip, and can be almost eliminated.

In this embodiment the length 1 of the first high density region inductance L is in the core 12 at the core 12 level 2 different from the length of said second high density region inductance L, however these lengths may be equal to each other depending on the required characteristics by adjusting the number of turns 17 of the wire to the large numbers 1 and L2 at the first and second high density region inductances. In contrast, if these lengths are changed, the L value of the first high-density inductor region L1 and the L value 2 of the second high-density inductor region L are changed. Therefore, the peak of the impedance curve can be distributed, and it can be expected to secure the impedance in a further wide band.

In the inductor element 21 according to the present embodiment, as described above, the wire 17 is wound in multiple layers as two layers L1 and L2 in the first and second high-density inductance regions, while the wire 17 is wound around the electric charge in a single layer in the low-density inductor region L3. In this case, in the first high-density area inductance size 1, the wire 17 is wound by 15 turns by 8 turns in length, and thus the winding density is 15/8= 1.875. In the second high-density inductor region L2, the wire winds the coil of fig. 1 by 6 turns in a length of 10 turns, and thus the winding density is 10/6-1.7. The winding density 1 may be the same in the first high-density inductance region L or may be different from the winding density 2 in the second high-density inductance region L. The difference 1 of the first high-density inductance region L between the winding densities and the winding density 2 in the second high-density inductance region L may be adjusted according to the required characteristics. A method of distinguishing the winding density in the first high-density inductor region L1 from the winding density in the second high-density inductor region L, for example, fig. 2 may be a method of omitting some turns in the outer layers of the two layers from one of the first and second high-density inductor regions L1 and L2.

As described above, as long as the winding density of the electric wire 17 is changed by selecting between the single-layer winding and the multi-layer winding, even if the electric wire 17 is wound such that the electric wire 17 contacts the electric wire 17 in one turn in the adjacent other turn. The winding density can be varied per revolution. Therefore, the position of the electric wire 17 is not easily shifted on the core 12, and variations in inductance value due to unexpected changes in the winding density of the electric wire 17 can be reduced. In addition, the magnetic coupling degree between the low-density inductor regions L is 3, and 1 and L2 of each of the first and second high-density inductor regions L may be increased.

Regarding the number of turns of the wire 17 in the three inductor regions L1 to L3, the number of turns in the first high-density inductor region L1 is 15 turns, the number of turns in the second high-density inductor region L2 is 10 turns, and the number of turns in the low-density inductor region L3 is 5 turns. Therefore, with respect to the values of L in the three inductor regions L1 through L3, the value of L in the first high-density inductor region L1 is the largest, the value of L in the second high-density inductor region L2 is the second largest, and the values of L1 and L2 are the smallest between the first and second high-density inductor regions L at the low-density inductor region LL value 3.

Regarding the magnitude relationship between the L values as described above, the arrangement order of the three inductor regions L1 to L3 is different from the arrangement order of the three chip inductors 1 to 3 shown in fig. 3. 6. One advantage of the low density inductance region L that minimizes the value of L3 is that 1 and L2, which are located between the first and second high density inductor regions on L, are considered below as in this embodiment.

The magnetic material (e.g., ferrite) forming the drum core 13 and the plate core 16 has a very high magnetic permeability μ of a megahertz band frequency, and thus causes adjacent inductors to be strongly coupled to each other. In particular, in the case of a magnetic path configuration in which the plate-shaped core 16 is closed, if λ is installed, the coupling coefficient in the low frequency range is almost 1 (full coupling) at any position in the closed magnetic path. However, even in the case of adopting the closed magnetic circuit configuration, in a range of a higher frequency having several hundred mhz, the magnetic permeability μ decreases, and the coupling coefficient decreases. In such a frequency range, the smaller the distance between the inductors, the stronger the magnetic coupling.

As in the present embodiment, when the low-density inductor region L3 in which the L value is smallest is located between the first high-density inductor region L1 in which the L value is large and the L2 of the second L2 in the longitudinal direction of the single core part 12, the low-density region inductance No. 3 is weakly magnetically coupled at the center to both sides of the high-frequency region on the high-density region inductances No. 1 and L2, and therefore, the inductance value increases.

On the other hand, the high-density inductor regions L1 and L2 arranged on both sides are weakly coupled to the low-density inductor region L3 at the center. However, since the L value in the central low-density inductor region L3 is small, the increase in the L value is very small.

With respect to the relationship between the first and second high-density inductor regions L1 and L2, which are respectively disposed at one end and the other end with the low-density inductor region L3 interposed therebetween, the first and second inductor regions L1 and L2 are separated, and thus are hardly affected from each other, and are not substantially coupled to each other.

That is, only the low-density inductor region L3 for high-frequency characteristics disposed at the center is affected by the high-density inductor regions L1 and L2 adjacent thereto, and the L value thereof substantially increases.

In contrast, fig. 2 is a sectional view schematically showing an inductor component 11 as a comparative example, the inductor component 11 employing the arrangement order of three chip inductors 1 to 3 connected in series as shown in fig. 1. 6. In fig. 2, like reference numerals are applied to like components corresponding to those shown in fig. 1. In fig. 1, redundant description is omitted.

The inductor component 11 shown in fig. 1 includes: the inductor region shown in fig. 2 has three inductor regions L1 to L3 in which the electric wires 17 are arranged in the longitudinal direction of the core 12 and have different winding densities from each other, similarly to the case of the inductor component 21 shown in fig. 2. 1. However, the array sequence of the three inductor regions L is 1 to L3 of the diagram shown in the inductor assembly 11. 2 is different from the case of the inductance component, the graph shown in 21. 1. That is, the inductor component 11 shown in fig. 1 has the following structure. As shown in fig. 2, the arrangement order of the three inductor regions L1 to L3 is determined such that the first high-density inductor region L1 and the second high-density inductor region L2 having higher winding density are located at the left end and the center portion in the drawing. The region of the core 12 shown in fig. 2 and the low-density inductor region L3 are due to the single layer winding, with the relatively lower winding density winding being located at the right end of fig. 2.

Regarding the number of turns of the wire 17 in each of the three inductor regions L1-L3, the number of turns in the first high-density inductor region L1 is 15 turns, and the number of turns in the second high-density inductor region L1 is 15 turns. Inductor region L2 is 10 turns and the number of turns in low density inductor region L3 is 5 turns. Therefore, regarding the L values in the three inductor regions L1 to L3, the L value in the first high-density inductor region L1 is the largest, the L value in the second high-density inductor region L is the second largest in fig. 2, and the L value in the low-density inductor region L3 is the smallest.

The magnitude relation between the above L values is equal to the magnitude relation between the L values of the three chip inductors 1 to 3 shown in fig. 3. 6. That is, if the second terminal electrode 19 of the inductor component 11 shown in fig. 1 is provided on the second terminal electrode 19, the second terminal electrode 19 is provided on the second terminal electrode 19. The high-frequency line 6 shown in fig. 2 is connected to the high-frequency line 6 shown in fig. 2. The first high-density inductance region L1 having the largest value of L corresponds to the chip inductor 1 where the second high-density inductor region L2 having the second largest value of L corresponds to the chip inductor 2 and the low-density inductor region L3 having the smallest value of L corresponds to the chip inductor 3.

As described above, as long as the figures shown in the three-chip inductors 1 to 3. As shown in fig. 6, the inductor assembly shown in fig. 6 is unified into one chip, and an inductor assembly 11 is provided. As shown in fig. 2, the following advantages can be obtained.

The configuration in fig. 1 is utilized. As shown in fig. 6, the chip inductors 1 to 3 are electrically and mechanically bonded to the pads 4 and 5 on the substrate by a method such as solder bonding, and mounted, so that a gap is inevitably generated between the chip inductors 1 to 3. In contrast, in the case where the inductor components 11 are unified into one chip as shown in fig. 1, the inductor components 11 are integrated into one chip. As shown in fig. 2, the above-described gap can be eliminated. Since the gap is eliminated, the adjacent regions in the inductor regions L1 to L1 increase the L value of the entire inductor assembly 11 even if the total number of turns of the inductor regions L1 to L3 is equal to the total number of turns of the chip inductor, although the low frequency region in fig. 3 is strongly coupled in the low frequency region. 1 to 3, fig. 6. Since the entire L value is increased, in the inductor section 11, the requested L value can be realized by a smaller number of turns than in the configuration in fig. 3. 6. The distance between the windings can be increased by this amount if desired. Therefore, the capacitance can be reduced.

In the case of the inductor component 21 according to the embodiment shown in fig. 1, the above-described advantages can be similarly obtained.

However, the inventors of the present application have thought that it is practically useless to collectively arrange the three inductor regions L1 to L3 in the inductor component 11 in one chip based on the magnitude relationship between the L values of the three chips. The inductors 1 to 3 shown in fig. 1 are constituted by the inductors 1 to 3. For example 6 in the frequency region of a few gigahertz. Since the outer shape of the inductor component 11 is sufficiently small in terms of the wavelength of the frequency used, the interval 3 between the three inductor regions L1 to L is the inductor component 11 in 1 to L3 that is sufficiently small in terms of wavelength regardless of the position of the inductor region L. Therefore, the above-described isolation deterioration rarely occurs. The arrangement 1 to L3 of the inductor region L are considered to have a high frequency region at a frequency of a millimeter wave of 20GHz or higher. If the frequency is lower than that of the millimeter wave, a plurality of inductor regions L1 to L3 are arranged in the inductor assembly 11. Unifying them into one chip eliminates the need to arrange the region where the L value is small, i.e., the low-density inductor region L3 on the high-frequency side.

Fig. 3 shows the impedance-frequency characteristic of the inductor component 21 according to the example shown in fig. 2. In fig. 1, the impedance-frequency characteristics of the inductor component 11 of the comparative example shown in fig. 1 are shown by solid lines.

The resonance frequency of the RLC parallel resonant circuit is determined by 1/{2 pi (LC) 1/2 }. In this embodiment, the equivalent L value of the low-density inductor region L3 having a low equivalent C value is increased by magnetic coupling between the adjacent high-density inductor regions L1 and L2. Therefore, the resonance frequency of the low-density inductor region L3 becomes lower than the inductor assembly 11.

The second peak 21 counted from the left side of the impedance-frequency characteristic of the inductance component represents 3 by the solid line due to the resonance of the inductor region L, the resonance frequency of which is lowered. The peak value is shifted leftward compared with the peak value of the impedance-frequency characteristic of the inductor component 11 indicated by the broken line in fig. 2.

In the inductor component 21 (solid line), the second peak from the left side of fig. 5 is a solid line. The graph in fig. 3 is caused by resonance in inductor region L3 where the equivalent C value is less than the equivalent C value of inductor region L2. Therefore, the impedance curve after the peak is located at a position higher than the position of the inductor component 11 (broken line). This is because the impedance curve after the peak has a capacitance characteristic of (Z ═ 1/jwC).

As shown in fig. 3, the inductor component 21 according to the example shown in fig. 3 is disposed near the second peak at a position near the second peak from the left. The impedance of fig. 1 can achieve a higher impedance than the impedance of the inductor component 11 according to the comparative example shown in fig. 1. Referring to fig. 2, high impedance can be ensured over a wide band.

Fig. 4 is a sectional view schematically showing an inductor component 31 according to a second embodiment of the present disclosure. In fig. 4, the same reference numerals are applied to the same components corresponding to those in fig. 3.

The diagram shown in inductor assembly 31. 4 includes two wires 17 a and 17b connected between a pair of terminal electrodes 18 and 19. When the two wires 17 one and 17b are connected between the pair of terminal electrodes 18 and 19, this can reduce the resistance value 31 of the inductor element as compared with the case where only one of the wires 17 one and 17b is connected.

Indicating that the cross-sections 17b of the second conductors are engaged in order to clarify the difference 17 between the first conductors-first and second lines 17

In the inductor component 31 according to the second embodiment shown in fig. 2, 4, the wires 17 one and 17b form three inductor regions L1 to L3 arranged in the longitudinal direction 12 of the core and having mutually different winding densities 17 one and 17b of the wires, and the low-density inductance region L3 is located between the first and second high-density inductor regions L1 and L similarly to the case of the inductor assembly 21 shown in fig. 2, the inductor assembly 21 in fig. 2 is similar in structure to the inductor assembly 21 shown in fig. 2. 1. In other words, the first high-density inductor region L1, the low-density inductor region L3, and the second high-density inductor region L2 are arranged in this order from the left side in fig. 4.

In this case, the wires 17 one and 17b are wound by 20 turns with the size 1 larger than the inductance of the first high-density region having a length of 10 turns, and thus the winding density is twenty-zero tenths = 2. The first and second wires 17 a and 17b are wound by 18 turns in the second high-density inductance region L2 with a length of 10 turns, and thus, the winding density is 18/10= 1.8. The first and second wires 17 a and 17b are wound with 6 turns and have a length of 12 turns to have a size of 3 in a low density area, so that the winding density is 6/12= 0.5. In short, in the first high-density inductor region L1, the winding density is highest, in the second high-density inductor region L2, the winding density is the second highest, and in the low-density inductor region, the winding density is lowest.

In the inductor element 31 according to the second embodiment, the first and second conductive lines 17 a and 17b are wound in a single layer while being alternately arranged in the low density region with the inductance of large 3, and one of the first and second conductive lines 17 a and 17b, for example, the first line 17 a is wound in a lower layer, and the other of the first and second conductive lines 17 a and 17b, for example, the second line 17b is wound in the high density inductor regions L1 and L2, with a metal wire in an upper layer.

With regard to the turns 17 one and 17b of the wire at 1 to L3 of the three inductor regions L, respectively, the first and second wires 17 one and 17b are electrically connected in parallel, so that the two wires of a pair behave like a thick rectangular wire. It is reasonable to consider the number of turns as one of the wires. Describing the number of turns in this regard, the number of turns in the first high density inductor region L1 is 10 turns and the number of turns in the low density inductor region L3. In the second high-density inductor region L2, the number of turns is 6 turns, and the number of turns is 9 turns. Therefore, with respect to the L values in the three inductor regions L1 through L3, the L value in the first high-density inductor region L1 is the largest and the L value in the second high-density inductor region L2 is the second. The value of L is the smallest in the low-density inductor region L3 between the first high-density inductor region L1 and the second high-density inductor region L2.

In addition, in the second embodiment described above, the two lead wires 17 one and 17b are connected between the pair of terminal electrodes 18 and 19, but three or more wires may be connected if necessary.

The slab core 16 is provided in each of the inductor assemblies 21 and 31 according to the first and second embodiments.

Although the illustrated embodiments are examples, structures according to different embodiments may be partially replaced or combined. Although some embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. Accordingly, the scope of the present disclosure is to be determined solely by the appended claims.

Claims (10)

1. An inductor assembly comprising: a core including a core portion extending in a longitudinal direction; at least one wire is helically wound around the core; and a pair of terminal electrodes electrically connected to respective ends of the wire, wherein, when the winding density indicates the number of turns of the wire per unit length in the longitudinal direction of the core, a plurality of inductor regions having mutually different winding densities of the wire are arranged in the longitudinal direction of the core, and a low-density inductor region having a relatively low winding density is located between first and second high-density inductor regions having a relatively high winding density.

2. The inductor component of claim 1, wherein a length of the first high-density inductor region in a length direction of the core is different from a length of the second high-density inductor region in the length direction of the core.

3. The inductor component of claim 1, wherein a length of the first high-density inductor region in a length direction of the core is the same as a length of the second high-density inductor region in the length direction of the core.

4. The inductor assembly of claim 1, wherein a winding density in the first high-density inductor region is different than a winding density in the second high-density inductor region.

5. The inductor assembly of claim 1, wherein a winding density in the first high-density inductor region is the same as a winding density in the second high-density inductor region.

6. The inductor component according to claim 1, wherein the low-density inductor region located between the first and second high-density inductor regions is located at a central portion in a length direction of the core.

7. The inductor component of claim 1, wherein the wire is wound in a single layer in the low-density inductor region and in multiple layers in the high-density inductor region.

8. The inductor component according to claim 7, wherein the wire comprises a single wire connected between the pair of terminal electrodes, the single wire wound in the single layer in the low-density inductor region, and the single wire wound in a high-density inductor region in multiple layers.

9. The inductor component of claim 7, wherein the wiring comprises a plurality of wirings connected between the pair of terminal electrodes, the plurality of wirings being sequentially arranged in the single layer of the low-density inductor region, and the plurality of wirings being wound with metal in a plurality of layers in a high-density inductor region.

10. The inductor assembly according to claim 1, wherein the core is a drum-shaped core made of a magnetic material and includes a pair of flange portions provided at respective ends of the core portion, and wherein the inductor assembly further includes a plate-shaped core made of a magnetic material and bridging the pair of flange portions.

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