The present invention relates to a coil component and, more particularly, to a coil component in which three planar spiral coils are magnetically coupled to one another.
Typical common mode filters have a structure in which two planar spiral coils are magnetically coupled to each other and are widely used to remove common mode noise superimposed on differential transmission lines. In recent years, a transmission line composed of three lines as one set is sometimes used, and thus there is required a coil component in which three planar spiral coils are magnetically coupled to one another as a coil component for removing common mode noise superimposed on such a transmission line.
A coil component in which three planar spiral coils are magnetically coupled to one another is described in Japanese Patent No. 6,586,878, JP 2020-038979A, and Japanese Patent No. 6,678,292. Japanese Patent No. 6,586,878 (FIG. 2 thereof), JP 2020-038979A (FIG. 3 thereof), and Japanese Patent No. 6,678,292 (FIG. 3 thereof) disclose coil components having a structure in which conductor layers each having two planar spiral coils and conductor layers each having one planar spiral coil are alternately stacked.
However, in the coil components described in Japanese Patent No. 6,586,878, JP 2020-038979A, and Japanese Patent No. 6,678,292, high-frequency characteristics, particularly, mode conversion characteristics (Scd21) involving conversion of a differential signal component into a common mode noise component deteriorate due to floating capacitance generated between planar spiral coils in second and third layers.
It is therefore an object of the present invention to prevent deterioration in high-frequency characteristics due to floating capacitance in a coil component having three planar spiral coils.
A coil component according to the present invention includes: a plurality of conductor layers stacked one on another through insulating layers and having first, second, and third planar spiral coils with the same number of turns; first, second, and third terminal electrodes connected respectively to one ends of the first, second, and third planar spiral coils; and fourth, fifth, and sixth terminal electrodes connected respectively to the other ends of the first, second, and third planar spiral coils. The plurality of conductor layers include first, second, third, and fourth conductor layers stacked one on another in this order. The first and third planar spiral coils are formed in the first and third conductor layers, the second planar spiral coil is formed in the second and fourth conductor layers. The pattern width of the second planar spiral coil formed in the second conductor layer is smaller than that of the second planar spiral coil formed in the fourth conductor layer, or the pattern width of each of the first and third planar spiral coils formed in the third conductor layer is smaller than that of each of the first and third planar spiral coils formed in the first conductor layer.
According to the present invention, the pattern width of the second planar spiral coil formed in the second conductor layer or the pattern widths of the first and third planar spiral coils formed in the third conductor layer are selectively reduced, so that the floating capacitance generated between the second and third conductor layers is reduced. This makes it possible to enhance high-frequency characteristics such as mode conversion characteristics as compared with conventional coil components having three planar spiral coils.
In the present invention, the second planar spiral coil formed in the second conductor layer may not overlap the first and third planar spiral coils formed in the third conductor layer in a plan view. This further reduces the floating capacitance generated between the second and third conductor layers, whereby high-frequency characteristics can be further enhanced.
In the present invention, the thickness of the second planar spiral coil formed in the fourth conductor layer may be larger than that of the second planar spiral coil formed in the second conductor layer. This can suppress an increase in the DC resistance of the second planar spiral coil.
As described above, according to the present invention, it is possible to prevent deterioration in high-frequency characteristics due to floating capacitance in a coil component having three planar spiral coils.
The above features and advantages of the present disclosure will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which:
Preferred embodiments of the present disclosure will be explained below in detail with reference to the accompanying drawings.
As illustrated in
The terminal electrodes 51 to 53 are provided along one long side of the coil component 1 extending in the x-direction, and the terminal electrodes 54 to 56 are provided along the other long side of the coil component 1 extending in the x-direction. Although not particularly limited, the terminal electrodes 51, 53, 54, and 56 are disposed at the corners of the coil component 1 and are thus each exposed to three side surfaces (xy surface, xz surface, and yz surface) of the coil component 1. On the other hand, the remaining terminal electrodes 52 and 55 are exposed to two surfaces (xy surface and xz surface) of the coil component 1. Further, although not particularly limited, the terminal electrodes 51 to 56 are formed by a thick film plating method, and the thickness of each thereof is sufficiently larger than an electrode pattern formed by a sputtering method or a screen printing.
As illustrated in
The conductor layer 10 is formed on the surface of the insulating layer 60. As illustrated in
The conductor layer 10 is covered with the insulating layer 70. As illustrated in
The conductor layer 20 is formed on the surface of the insulating layer 70. As illustrated in
The conductor layer 20 is covered with the insulating layer 80. As illustrated in
The conductor layer 30 is formed on the surface of the insulating layer 80. As illustrated in
The conductor layer 30 is covered with the insulating layer 90. As illustrated in
The conductor layer 40 is formed on the surface of the insulating layer 90. As illustrated in
The conductor layer 40 is covered with the insulating layer 100. As illustrated in
The resin layer 4 and terminal electrodes 51 to 56 are provided on the surface of the insulating layer 100. The terminal electrodes 51 to 56 are provided at positions overlapping the vias 101 to 106, respectively, and are thus connected to the connection patterns 41 to 46, respectively.
As illustrated in
The circuit board 5 illustrated in
On the circuit board 5, signal lines D1 to D6 are connected respectively to the land patterns P1 to P6. The three signal lines D1 to D3 constitute a line group S1 and the three signal lines D4 to D6 constitute a line group S2. For example, the line group S1 serves as an input-side line group, and the line group S2 serves as an output-side line group. Data of three signals transmitted by the line groups S1 and S2 are represented as a potential difference between two signals. For example, in the line group S1, data are represented by the magnitude relation between the levels of the signal lines D1 and D2, the magnitude relation between the levels of the signal lines D1 and D3, and the magnitude relation between the levels of the signal lines D2 and D3. The same applies to the line group S2. Thus, in this example, 3-bit data can be transmitted at a time. By inserting the coil component 1 according to the present embodiment between the thus configured line groups S1 and S2, common mode noise superimposed on the three signals can be removed.
As illustrated in
The radial widths of the planar spiral coils C1a to C3a and C1b to C3b are W1a to W3a and W1b to W3b, respectively. The thickness of each of the planar spiral coils C1a and C3a is H13a, the thickness of the planar spiral coil C2a is H2a, the thickness of each of the planar spiral coils C1b and C3b is H13b, and the thickness of the planar spiral coil C2b is H2b. In the present embodiment,
W2b>W1a=W3a=W1b=W3b>W2a and
H13a=H13b>H2a=H2b are satisfied.
By thus reducing the pattern width W2a of the planar spiral coil C2a, the floating capacitance between the planar spiral coil C2a positioned in the conductor layer 20 and the planar spiral coils C1b and C3b positioned in the conductor layer 30 is reduced, whereby it is possible to prevent deterioration in high-frequency characteristics due to the floating capacitance. For further reduction in the floating capacitance, the planar spiral coil C2a and the planar spiral coils C1b, C3b should preferably not overlap each other in a plan view. On the other hand, when the pattern width W2a of the planar spiral coil C2a is reduced, the DC resistance of the inductor L2 increases, and the capacitance balance between the inductor L2 and the inductors L1, L3 changes. Thus, in order to cancel the reduction in the width W2a, the pattern width W2b of the planar spiral coil C2b positioned in the conductor layer 40 is made larger than the pattern width W2a. This can suppress an increase in the DC resistance of the inductor L2 and maintain the capacitance balance between the inductor L2 and the inductors L1, L3.
The widths W1a, W3a, W1b, and W3b may not necessarily be the same as each other and may not necessarily be larger than the width W2a and smaller than the width W2b. The thicknesses H13a and H13b may not necessarily be the same as each other and the thicknesses H2a and H2b may not necessarily be the same as each other. Further, the thicknesses H13a and H13b may not necessarily be larger than the thicknesses H2a and H2b.
As described above, in the coil component 1 according to the present embodiment, the pattern width W2a of the planar spiral coil C2a is reduced and, instead, the pattern width W2b of the planar spiral coil C2b is increased, whereby it is possible to reduce the floating capacitance generated between the planar spiral coil C2a and the planar spiral coils C1b, C3b without significantly disrupting DC resistance and capacitance balance between the inductors L1 to L3.
A coil component according to the first modification illustrated in
W1a=W3a>W2a=W2b>W1b=W3b is satisfied. Thus, even when the pattern widths W2a and W2b of the planar spiral coils C2a and C2b are the same, the floating capacitance between the planar spiral coil C2a positioned in the conductor layer 20 and the planar spiral coils C1b, C3b positioned in the conductor layer 30 is reduced by reducing the pattern widths W1b and W3b of the planar spiral coils C1b and C3b, so that it is possible to prevent deterioration in high-frequency characteristics due to the floating capacitance. On the other hand, when the pattern widths W1b and W3b of the planar spiral coils C1b and C3b are reduced, the DC resistances of the inductors L2 and L3 increase, and the capacitance balance between the inductor L2 and the inductors L1, L3 changes. Thus, in order to cancel the reduction in the pattern widths W1b and W3b, the pattern widths W1a and W3a of the planar spiral coils C1a and C3a positioned in the conductor layer 10 are made larger than the pattern widths W1b and W3b. This can suppress an increase in the DC resistances of the inductors L1 and L3 and maintain the capacitance balance between the inductor L2 and the inductors L1, L3.
A coil component according to the second modification illustrated in
W2b>W2a and
W1a=W3a>W1b=W3b are satisfied. Thus, the pattern width W2a of the planar spiral coil C2a may be smaller than the pattern width W2b of the planar spiral coil C2b, and the pattern widths W1b and W3b of the planar spiral coils C1b and C3b may be smaller than the pattern widths W1a and W3a of the planar spiral coils C1a and C3a.
A coil component according to the third modification illustrated in
W2b>W2a and
H2b>H2a are satisfied. Thus, instead of suppressing an increase in the pattern width W2b of the planar spiral coil C2b, the thickness H2b of the planar spiral coil C2b may be larger than the thickness H2a of the planar spiral coil C2a.
It is apparent that the present disclosure is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the disclosure.
For example, although the conductor layers 10, 20, 30, and 40 are stacked in this order on the substrate 2 in the above embodiment, they may be stacked in the reverse order (40, 30, 20, and 10 from the bottom).
Further, the insulating layer 80 may be made of a material having a lower dielectric constant than those of the insulating layers 60, 70, 90, and 100 so as to further reduce the floating capacitance generated between the planar spiral coil C2a and the planar spiral coils C1b and C3b.
Number | Date | Country | Kind |
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2020-162538 | Sep 2020 | JP | national |