Laminated common mode filter

Abstract

The laminated common mode filter of the present invention has a filter stack body formed by stacking a stack body in which a capacitor pattern, a floating pattern, an inductor pattern, and a ground pattern are disposed under a coil stack body including a plurality of coils constituting mutually different channels, the resonant frequency characteristic may vary according to the inductor pattern.

Description

Technical Field

[0001] The present invention relates to a stacked common mode filter that allows differential signal currents to pass through in an electronic device using high-speed signal lines and removes common mode noise currents. Background Art

[0002] Mobile terminals generally adopt the Mobile Industry Processor Interface (MIPI) D-PHY standard as the digital data transmission standard. The MIPI D-PHY standard is a digital data transmission standard that connects the main circuit of a mobile terminal to a display or a camera, and refers to a method of transmitting data using differential signals on two transmission lines.

[0003] With the rapid increase in the amount of data transmitted and received within a mobile terminal, the mobile terminal requires a transmission method that can transmit and receive data at a faster speed than the MIPI D-PHY standard.

[0004] Therefore, in the mobile terminal industry, research has recently been carried out on applying the MIPI C-PHY standard to mobile terminals. The MIPI C-PHY standard uses three transmission lines, transmits different voltages from the transmitting side to each transmission line, and performs differential output on the receiving side by taking the difference between each line.

[0005] The content described in the background art is for helping to understand the background of the present invention and may include content that does not belong to the publicly available prior art. Summary of the Invention

[0006] The present invention is proposed in view of the above circumstances, and the object of the present invention is to provide a stacked common mode filter in which a stack including a capacitor pattern, a floating pattern, an inductor pattern, and a ground pattern is provided below the filter stack body, thereby enabling control of characteristics such as resonance points (resonance frequencies) and cut-offs.

[0007] Technical Solution for Solving the Problem

[0008] To achieve the above object, a stacked common mode filter according to an embodiment of the present invention may include: a first stack provided with a first coil pattern, a second coil pattern, and a third coil pattern; a second stack provided with a fourth coil pattern, a fifth coil pattern, and a sixth coil pattern and disposed below the first stack; and a third stack disposed below the second stack. The third stack may include: a plurality of capacitor patterns disposed below the second stack; a floating pattern disposed below the plurality of capacitor patterns and configured to form additional capacitance by overlapping with the plurality of capacitor patterns; a ground pattern disposed below the floating pattern; and an inductor pattern disposed between the floating pattern and the ground pattern. A first end of the inductor pattern may be connected to the floating pattern, and a second end of the inductor pattern may be connected to the ground pattern.

[0009] The third stack may include a ninth sheet, a plurality of capacitor patterns spaced apart from each other on a first surface of the ninth sheet, a tenth sheet below the ninth sheet, and a floating pattern on a first surface of the tenth sheet, the floating pattern forming a plurality of overlapping regions by overlapping with the plurality of capacitor patterns and configured to form additional capacitance in the plurality of overlapping regions.

[0010] The third stack may further include a ground pattern below the tenth sheet and the inductor pattern between the tenth sheet and the ground pattern, the inductor pattern including a first end connected to the floating pattern and a second end connected to the ground pattern.

[0011] The third stack may further include an eleventh sheet between the tenth sheet and the ground pattern and a twelfth sheet between the eleventh sheet and the ground pattern. The inductor pattern may include a first inductor pattern and a second inductor pattern. The first inductor pattern is on a first surface of the eleventh sheet and includes a first end connected to the floating pattern through a via passing through the eleventh sheet and a second end spaced apart from the first end. The second inductor pattern is on a first surface of the twelfth sheet and includes a first end connected to the ground pattern and a second end connected to the second end of the first inductor pattern through a via passing through the eleventh sheet.

[0012] The stacked common mode filter may further include a first magnetic sheet disposed above the first stack and a second magnetic sheet between the second stack and the third stack. The stacked common mode filter may further include a third magnetic sheet disposed below the third stack.

[0013] A filter stack formed by stacking the first stack, the second stack, and the third stack may have a first resonance frequency and a second resonance frequency higher than the first resonance frequency. As the length of the inductor pattern increases, the second resonance frequency may shift to a higher frequency.

[0014]

Advantages of the Invention

[0015] According to the present invention, the stacked common-mode filter allows the distance (pitch) between the coil patterns of each channel to be kept constant, so that the resistance and inductance of the coil patterns forming each channel are consistent.

[0016] In addition, by providing terminal patterns for connecting to external electrodes at the uppermost and lowermost portions of the filter stack, the stacked common-mode filter has the effect of minimizing changes in the inductance characteristics and common-mode attenuation characteristics of the coil patterns.

[0017] In addition, by placing a capacitor pattern and a floating pattern below the coil stack, an additional depression is formed in the common-mode attenuation characteristic, whereby the stacked common-mode filter has the effect of expanding the attenuation frequency band.

[0018] In addition, an additional pole (i.e., additional capacitance) formed by the capacitor pattern and the floating pattern and a pole formed by the coil pattern of the electrode stack enable the stacked common-mode filter to achieve broadband characteristics.

[0019] In addition, by forming a constant distance (pitch) between the channels, the stacked common-mode filter has the effect of minimizing changes in the inductance characteristics of the coil patterns.

[0020] In addition, the stacked common-mode filter has the effect of enhancing the magnetic coupling (i.e., electromagnetic coupling) between the first coil to the third coil and minimizing the attenuation of differential signals.

[0021] In addition, the stacked common-mode filter can form the electrode stack by stacking sheets with two or fewer vias, thus simplifying the manufacturing process.

[0022] That is, in the stacked common-mode filter, the terminal patterns are provided at the uppermost and lowermost portions of the electrode stack, the second coil pattern and the third coil pattern of the second channel are located between the first coil pattern and the sixth coil pattern of the first channel, and the fourth coil pattern and the fifth coil pattern of the third channel are located between the third coil pattern and the sixth coil pattern. Therefore, the number of vias required to connect the coil patterns can be minimized, and two or fewer vias are formed in each sheet.

[0023] In addition, the laminated common mode filter has the effect of increasing capacitance without adding an electrode layer including a coil pattern or increasing the area of the coil pattern, thereby achieving a larger capacitance than the conventional laminated common mode filter within the same size.

[0024] In addition, the laminated common mode filter has the effect of changing the second resonance frequency by adjusting the length of the inductor pattern.

[0025] In addition, since a short - circuit circuit formed by the floating pattern, the inductor pattern, and the ground pattern is configured by a third stack disposed below the coil stack, the laminated common mode filter can easily adjust and control the second resonance frequency.

[0026] In addition, by placing or removing a magnetic sheet at the lowermost part of the filter stack, the laminated common mode filter has the effect of being able to adjust the distance between the first resonance frequency and the second resonance frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective view of a laminated common mode filter according to an embodiment of the present invention.

[0028] Figure 2 is for explaining Figure 1 the exploded perspective view of the filter stack in

[0029] Figure 3 is for explaining Figure 2 the exploded perspective view of the first stack in

[0030] Figure 4 is for explaining Figure 3 the drawing of the first thin sheet in

[0031] Figure 5 is for explaining Figure 3 the drawing of the second thin sheet in

[0032] Figure 6 is for explaining Figure 3 the drawing of the third thin sheet in

[0033] Figure 7 is for explaining Figure 3 the drawing of the fourth thin sheet in

[0034] Figure 8 is for explaining Figure 2 the exploded perspective view of the second stack in

[0035] Figure 9 is for explaining Figure 3 the drawing of the fifth thin sheet in

[0036] Figure 10 is a diagram for explaining Figure 8 the sixth thin sheet in

[0037] Figure 11 is a diagram for explaining Figure 8 the seventh thin sheet in

[0038] Figure 12 is a diagram for explaining Figure 8 the eighth thin sheet in

[0039] Figure 13 is a cross-sectional view showing a vertical cross-section of a coil stack in Figure 2

[0040] Figure 14 is a diagram for explaining Figure 2 the exploded perspective view of the third stack in

[0041] Figure 15 is a diagram for explaining Figure 14 the ninth thin sheet in

[0042] Figure 16 is a diagram for explaining Figure 14 the tenth thin sheet in

[0043] Figure 17 is a diagram for explaining Figure 14 the eleventh thin sheet in

[0044] Figure 18 and 19 is a diagram for explaining Figure 14 the twelfth thin sheet in

[0045] Figure 20 is a diagram for explaining Figure 14 the thirteenth thin sheet in

[0046] Figure 21 is a diagram showing the equivalent circuit of a stacked common-mode filter according to an embodiment of the present invention.

[0047] Figures 22 to 24 is a diagram for comparing and explaining the characteristics of a stacked common-mode filter varying with the length (area) of an inductor pattern.

[0048] Figure 25 and 26 is an exploded perspective view for explaining a modified example of a stacked common-mode filter according to an embodiment of the present invention.

[0049] Figure 27 and 28 is for comparing and explaining Figure 26 the characteristics of a stacked common-mode filter with or without the third magnetic sheet shown in​

[0050] Figures 29 to 31 This is a diagram for comparing and explaining the characteristics of the stacked common-mode filter according to an embodiment of the present invention with those of an existing stacked common-mode filter. Detailed Embodiment

[0051] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0052] The provided embodiments are for more fully explaining the present invention to those skilled in the art to which the present invention pertains. The following embodiments can be modified in various other forms, and the scope of the present invention is not limited to the following embodiments. These embodiments are provided to make the present invention more thorough and complete, and to fully convey the idea of the present invention.

[0053] The terms used in this specification are for explaining specific embodiments and are not intended to limit the present invention. In addition, in this specification, unless otherwise clearly defined in the context, singular expressions may include plural expressions.

[0054] In the description of the embodiments, when it is described that each layer (film), region, pattern, or structure is formed "on" or "under" each substrate, layer (film), region, pad, or pattern, this includes two expressions, that is, including forming a layer "directly" on another layer or "indirectly inserting another layer between two layers". In addition, the reference for "on" or "under" each layer is based on the accompanying drawings.

[0055] The accompanying drawings are only for helping to understand the spirit of the present invention and should not be construed as limiting the scope of the present invention. In addition, in the accompanying drawings, for convenience and clarity of explanation, relative thickness, length, or size may be enlarged.

[0056] See Figure 1 , the stacked common-mode filter 100 according to an embodiment of the present invention includes a filter stack 110, a first external electrode 120, a second external electrode 130, a third external electrode 140, a fourth external electrode 150, a fifth external electrode 160, a sixth external electrode 170, a seventh external electrode 180, and an eighth external electrode 190. Hereinafter, the stacked common-mode filter 100 operating as a three-channel C-PHY common-mode filter will be described as an example.

[0057] The filter stack 110 is a stack of thin sheets, on which six coil patterns forming three channels, capacitor patterns for adjusting characteristics such as resonance frequency, floating patterns 522, inductor patterns 532 and 542, and a ground pattern 555 are arranged. The stacked common-mode filter 100 adjusts the resonance point (resonance frequency) offset, cut-off characteristics, etc. through the capacitor patterns and floating patterns 522 forming capacitance, the inductor patterns 532 and 542 constituting inductance, and the ground pattern 555 forming grounding.

[0058] See Figure 2 , the filter stack 110 includes a first stack 200, a second stack 300 disposed below the first stack 200, and a third stack 500 disposed below the second stack 300.

[0059] The first stack 200 is formed by stacking a plurality of sheets formed with metal patterns. For example, see Figure 3 , the first stack 200 includes a first sheet 210, a second sheet 220 disposed below the first sheet 210, a third sheet 230 disposed below the second sheet 220, and a fourth sheet 240 disposed below the third sheet 230.

[0060] Here, metal patterns corresponding to the terminal patterns 212 and 214 are formed in the first sheet 210, and metal patterns corresponding to the coil patterns 222, 232, and 242 are formed in the second sheet 220, the third sheet 230, and the fourth sheet 240.

[0061] See Figure 4 , a first terminal pattern 212 and a second terminal pattern 214 for connecting the coil pattern of the first electrode layer to the external electrode are formed on the first sheet 210.

[0062] The first terminal pattern 212 is located on the upper surface of the first sheet 210. The first end 212a of the first terminal pattern 212 is arranged adjacent to the center of the first sheet 210.

[0063] The second end 212b of the first terminal pattern 212 is arranged to align with the first side surface of the first sheet 210. Therefore, the second end 212b of the first terminal pattern 212 is exposed on the first side surface of the filter stack 110 and connected to the first external electrode 120.

[0064] The second terminal pattern 214 is disposed on the upper surface of the first sheet 210 at an interval from the first terminal pattern 212. The first end 214a of the second terminal pattern 214 is arranged adjacent to the center of the first sheet 210. The first end 214a of the second terminal pattern 214 is separated from the first end 212a of the first terminal pattern 212 by a preset distance.

[0065] The second end 214b of the second terminal pattern 214 is arranged to align with the first side surface of the first sheet 214. Therefore, the second end 214b of the second terminal pattern 214 is separated from the second end 212b of the first terminal pattern 212 by a preset distance, exposed on the first side surface of the filter stack 110, and connected to the third external electrode 140.

[0066] SeeFigure 5 The second thin sheet 220 is disposed below the first thin sheet 210. A first via hole V1 and a first coil pattern 222 forming a first channel are provided in the second thin sheet 220.

[0067] The first coil pattern 222 is disposed on the upper surface of the second thin sheet 220. The first coil pattern 222 is wound multiple times on the upper surface of the second thin sheet 220, thereby forming a first annular structure. The first coil pattern 222 is wound multiple times around a virtual winding axis passing through the center of the second thin sheet 220 to form a first annular structure.

[0068] The first end portion 222a of the first coil pattern 222 is disposed in the inner peripheral region of the first annular structure and is adjacent to the center of the second thin sheet 220. The first end portion 222a of the first coil pattern 222 is connected to the first end portion 212a of the first terminal pattern 212 through a via hole.

[0069] The second end portion 222b of the first coil pattern 222 is disposed in the outer peripheral region of the first annular structure and is aligned with the second side surface of the second thin sheet 220. Accordingly, the second end portion 222b of the first coil pattern 222 is exposed on the second side surface of the filter stack 110 and is connected to the fourth outer electrode 150.

[0070] The first via hole V1 is disposed adjacent to the center of the second thin sheet 220 and is spaced apart from the first end portion 222a of the first coil pattern 222. The first via hole V1 penetrates through the second thin sheet 220. The upper portion of the first via hole V1 is connected to the second terminal pattern 214. The lower portion of the first via hole is connected to a coil pattern formed in the third thin sheet 230, which will be described later.

[0071] See Figure 6 The third thin sheet 230 is disposed below the second thin sheet 220. A second coil pattern 232 forming a second channel is provided in the third thin sheet 230.

[0072] The second coil pattern 232 is disposed on the upper surface of the third thin sheet 230. The second coil pattern 232 is wound multiple times on the upper surface of the third thin sheet 230, thereby forming a second annular structure. The second coil pattern 232 is wound multiple times around a virtual winding axis passing through the center of the third thin sheet 230 to form a second annular structure.

[0073] The first end portion 232a of the second coil pattern 232 is disposed in the inner peripheral region of the second annular structure and is adjacent to the center of the third thin sheet 230. The first end portion 232a of the second coil pattern 232 is connected to the first end portion 214a of the second terminal pattern 214 through the first via hole V1 of the second thin sheet 220.

[0074] The second end 232b of the second coil pattern 232 is disposed in the outer peripheral region of the second annular structure and is aligned with the second side surface of the third sheet 230. The second end 232b of the second coil pattern 232 is disposed at a preset distance from the second end 222b of the first coil pattern 222, is exposed on the second side surface of the filter stack 110, and is connected to the fifth outer electrode 160.

[0075] See Figure 7 , the fourth sheet 240 is disposed below the third sheet 230, and a third coil pattern 242 that forms a second channel together with the second coil pattern 232 is provided in the fourth sheet 240.

[0076] The third coil pattern 242 is disposed on the upper surface of the fourth sheet 240. The third coil pattern 242 is wound multiple times on the upper surface of the fourth sheet 240 to form a third annular structure. The third coil pattern 242 is wound multiple times around a virtual winding axis passing through the center of the fourth sheet 240 to form a third annular structure.

[0077] The first end 242a of the third coil pattern 242 is disposed in the inner peripheral region of the third annular structure and is adjacent to the center of the fourth sheet 240. The first end 242a of the third coil pattern 242 is connected to the first end 232a of the second coil pattern 232 through a via hole and is connected to the first end 214a of the second terminal pattern 214 through the first via hole V1 of the second sheet 220.

[0078] The second end 242b of the third coil pattern 242 is disposed in the outer peripheral region of the third annular structure and is aligned with the second side surface of the fourth sheet 240. Therefore, the second end 242b of the third coil pattern 242 is disposed at a preset distance from the second end 222b of the first coil pattern 222.

[0079] The second end 242b of the third coil pattern 242 is disposed to be aligned with the second end 232b of the second coil pattern 232 and is exposed on the second side surface of the filter stack 110 to be connected to the fifth outer electrode 160 together with the second end 232b of the second coil pattern 232.

[0080] The second stack 300 is disposed below the first stack 200 and is formed by stacking a plurality of sheets on which metal patterns are formed. For example, see Figure 8, the second stack 300 includes a fifth sheet 310, a sixth sheet 320 located below the fifth sheet 310, a seventh sheet 330 located below the sixth sheet 320, and an eighth sheet 340 located below the seventh sheet 330. Here, metal patterns corresponding to the coil patterns 312, 322, 332 are formed in the fifth sheet 310, the sixth sheet 320, and the seventh sheet 330, and metal patterns corresponding to the terminal patterns 342, 344 are formed in the eighth sheet 340.

[0081] See Figure 9 , the fifth sheet 310 is disposed below the fourth sheet 240, and the fourth coil pattern 312 forming the third channel is disposed on the fifth sheet 310.

[0082] The fourth coil pattern 312 is located on the upper surface of the fifth sheet 310. The fourth coil pattern 312 is wound multiple times on the upper surface of the fifth sheet 310 to form a fourth annular structure. The fourth coil pattern 312 is wound multiple times around a virtual winding axis passing through the center of the fifth sheet 310 to form a fourth annular structure.

[0083] The first end 312a of the fourth coil pattern 312 is disposed in the inner peripheral region of the fourth annular structure and is adjacent to the center of the fifth sheet 310. The first end 312a of the fourth coil pattern 312 is connected to the first end 322a of the fifth coil pattern 322 through a via hole, and the first end 322a will be described later.

[0084] The second end 312b of the fourth coil pattern 312 is located in the outer peripheral region of the fourth annular structure and is aligned with the second side surface of the fifth sheet 310. The second end 312b of the fourth coil pattern 312 is exposed on the second side surface of the filter stack 110 and is connected to the sixth outer electrode 170.

[0085] See Figure 10 , the sixth sheet 320 is disposed below the fifth sheet 310. The fifth coil pattern 322 that forms the third channel together with the fourth coil pattern 312 is disposed on the sixth sheet 320.

[0086] The fifth coil pattern 322 is located on the upper surface of the sixth sheet 320. The fifth coil pattern 322 is wound multiple times on the upper surface of the sixth sheet 320 to form a fifth annular structure. The fifth coil pattern 322 is wound multiple times around a virtual winding axis passing through the center of the sixth sheet 320 to form a fifth annular structure.

[0087] The first end 322a of the fifth coil pattern 322 is disposed in the inner peripheral region of the fifth annular structure and is adjacent to the center of the sixth sheet 320. The first end 322a of the fifth coil pattern 322 is connected to the first end 312a of the fourth coil pattern 312 through a via hole.

[0088] The second end portion 322b of the fifth coil pattern 322 is disposed in the outer peripheral region of the fifth annular structure and is aligned with the second side surface of the sixth sheet 320. The second end portion 322b of the fifth coil pattern 322 is aligned with the second end portion 312b of the fourth coil pattern 312 and is exposed on the second side surface of the filter stack 110 to be connected to the sixth outer electrode 170 together with the second end portion 312b of the fourth coil pattern 312.

[0089] See Figure 11 , the seventh sheet 330 is located below the sixth sheet 320. A second via hole V2 and a sixth coil pattern 332 that forms a first channel together with the first coil pattern 222 of the first stack 200 are formed in the seventh sheet 330.

[0090] The sixth coil pattern 332 is located on the upper surface of the seventh sheet 330. The sixth coil pattern 332 is wound multiple times on the upper surface of the seventh sheet 330 to form a sixth annular structure. The sixth coil pattern 332 is wound multiple times around a virtual winding axis passing through the center of the seventh sheet 330 to form a sixth annular structure.

[0091] The first end portion 332a of the sixth coil pattern 332 is disposed in the inner peripheral region of the sixth annular structure and is adjacent to the center of the seventh sheet 330.

[0092] The second end portion 332b of the sixth coil pattern 332 is disposed in the outer peripheral region of the sixth annular structure and is aligned with the second side surface of the seventh sheet 330. The second end portion 332b of the sixth coil pattern 332 is disposed at a preset distance from the second end portion 312b of the fourth coil pattern 312 and the second end portion 322b of the fifth coil pattern 322 and is exposed on the second side surface of the filter stack 110 to be connected to the fourth outer electrode 150.

[0093] The second via hole V2 is disposed adjacent to the center of the seventh sheet 330 and is spaced apart from the first end portion 332a of the sixth coil pattern 332. The second via hole V2 is formed to penetrate the seventh sheet 330. The upper portion of the second via hole V2 is connected to the first end portion 312a of the fourth coil pattern 312 and the first end portion 322a of the fifth coil pattern 322. The lower portion of the second via hole V2 is connected to a third terminal pattern 342 formed in the eighth sheet 340, and the third terminal pattern 342 will be described later.

[0094] See Figure 12 , a third terminal pattern 342 and a fourth terminal pattern 344 for connecting the coil pattern of the second electrode layer to the outer electrode are formed in the eighth sheet 340.

[0095] The third terminal pattern 342 is located on the upper surface of the eighth sheet 340. The first end 342a of the third terminal pattern 342 is arranged adjacent to the center of the eighth sheet 340. The first end 342a of the third terminal pattern 342 is connected to the first end 312a of the fourth coil pattern 312 and the first end 322a of the fifth coil pattern 322 through the second via V2.

[0096] The second end 342b of the third terminal pattern 342 is arranged to align with the first side surface of the eighth sheet 340. Thus, the second end 342b of the third terminal pattern 342 is exposed on the first side surface of the filter stack 110 and is connected to the second external electrode 130.

[0097] The fourth terminal pattern 344 is located on the upper surface of the eighth sheet 340, spaced apart from the third terminal pattern 342. The first end 344a of the fourth terminal pattern 344 is connected to the first end 332a of the sixth coil pattern 332 through a via. The first end 344a of the fourth terminal pattern 344 is arranged adjacent to the center of the eighth sheet 340. The first end 344a of the fourth terminal pattern 344 is separated from the first end 342a of the third terminal pattern 342 by a preset distance.

[0098] The second end 344b of the fourth terminal pattern 344 is arranged to align with the first side surface of the eighth sheet 340. Therefore, the second end 344b of the fourth terminal pattern 344 is separated from the second end 342b of the third terminal pattern 342 by a preset distance and is exposed on the first side surface of the filter stack 110 to be connected to the first external electrode 120 together with the second end 212b of the first terminal pattern 212.

[0099] The first stack 200 and the second stack 300 form a coil stack 400, and the coil stack 400 includes coils forming three channels.

[0100] The coil stack 400 is configured such that the first coil pattern 222, the second coil pattern 232, the third coil pattern 242, the fourth coil pattern 312, the fifth coil pattern 322, and the sixth coil pattern 332 are stacked in sequence.

[0101] Here, the first coil pattern 222 and the sixth coil pattern 332 form a first coil, and the first coil is a series inductor constituting the first channel. The second coil pattern 232 and the third coil pattern 242 form a second coil, and the second coil is a series inductor constituting the second channel. The fourth coil pattern 312 and the fifth coil pattern 322 form a third coil, and the third coil is a series inductor constituting the third channel.

[0102] Thus, the coil stack 400 forms a stack in which the coil patterns of the first channel, the coil patterns of the second channel, the coil patterns of the second channel, the coil patterns of the third channel, the coil patterns of the third channel, and the coil patterns of the first channel are arranged (stacked) in sequence.

[0103] Therefore, in the stacked common mode filter 100 according to an embodiment of the present invention, the distance (spacing) between the coil patterns forming each channel can be kept constant, so that the resistance and inductance of the coil patterns forming each channel are kept consistent.

[0104] In addition, in the stacked common mode filter 100 according to an embodiment of the present invention, the variation of the inductance characteristics and the common mode attenuation characteristics of the coil patterns can be minimized by placing the terminal patterns for connecting to the external electrodes at the uppermost and lowermost portions of the coil stack 400. When the terminal patterns are provided only at the uppermost or lowermost portion, the inductance characteristics of each channel change, or the inductance characteristics of each coil pattern change, resulting in a change in the common mode attenuation characteristics.

[0105] In the stacked common mode filter 100 according to an embodiment of the present invention, the terminal patterns are provided at the uppermost and lowermost portions of the coil stack 400. The second coil pattern 232 and the third coil pattern 242 of the second channel are provided between the first coil pattern 222 and the sixth coil pattern 332 of the first channel. The fourth coil pattern 312 and the fifth coil pattern 322 of the third channel are provided between the first coil pattern 242 and the sixth coil pattern 332. Thus, the number of vias required to connect the coil patterns can be minimized. The stacked common mode filter 100 according to an embodiment of the present invention forms two or fewer vias in each sheet.

[0106] See Figure 13 , the first coil pattern 222 and the sixth coil pattern 332 are respectively provided at the upper and lower portions of the filter stack 110, thereby forming the first channel. The second coil pattern 232 and the third coil pattern 242 are arranged (stacked) in parallel between the first coil pattern 222 and the sixth coil pattern 332, thereby forming the second channel. The fourth coil pattern 312 and the fifth coil pattern 322 are arranged (stacked) in parallel between the third coil and the sixth coil, thereby forming the third channel.

[0107] Therefore, the stacked common mode filter 100 according to an embodiment of the present invention can be configured such that the distances (spacings) between the first channel and the second channel, the second channel and the third channel, and the third channel and the first channel are kept constant.

[0108] In addition, the stacked common mode filter 100 according to an embodiment of the present invention can minimize the variation of the inductance characteristics of the coil patterns by keeping the distance (interval) between the channels constant.

[0109] In addition, in the stacked common mode filter 100 according to an embodiment of the present invention, since the terminal patterns connecting the coil patterns to the external electrodes are provided at the uppermost and lowermost portions of the filter stack 110, the distances between the coil patterns and the terminal patterns can be made the same for all channels, thereby ensuring that the resistance and inductance of the coil patterns forming each channel are consistent.

[0110] In addition, the stacked common mode filter 100 according to an embodiment of the present invention can enhance the magnetic coupling (i.e., electromagnetic coupling) between the first coil to the third coil and minimize the attenuation of differential signals.

[0111] The third stack 500 is disposed below the second stack 300. The third stack 500 is formed by stacking a plurality of sheets on which metal patterns are formed.

[0112] For example, referring to Figure 14 , the third stack 500 includes a ninth sheet 510, a tenth sheet 520 located below the ninth sheet 510, an eleventh sheet 530 located below the tenth sheet 520, a twelfth sheet 540 located below the eleventh sheet 530, and a thirteenth sheet 510 located below the twelfth sheet 540. Metal patterns 411 to 416 and 422 for forming capacitance are formed on the ninth sheet 510 and the tenth sheet 520. Metal patterns 432 and 442 for forming inductance are formed on the eleventh sheet 530 and the twelfth sheet 540. A metal pattern 452 for forming a ground is formed on the thirteenth sheet 510.

[0113] The ninth sheet 510 is located below the eighth sheet 340. A plurality of capacitor patterns are disposed on the upper surface of the ninth sheet 510, and the capacitor patterns can be set as a plurality of patterns provided at the input end and the output end of the stacked common mode filter 100.

[0114] For example, referring to Figure 15 , the capacitor patterns include a first capacitor pattern 511, a second capacitor pattern 512, a third capacitor pattern 513, a fourth capacitor pattern 514, a fifth capacitor pattern 515, and a sixth capacitor pattern 516.

[0115] The first capacitor pattern 511 is disposed on the upper surface of the ninth sheet 510.

[0116] A first end portion 511a of the first capacitor pattern 511 is disposed adjacent to the center of the ninth sheet 510.

[0117] A second end portion 511b of the first capacitor pattern 511 is disposed to align with the first side surface of the ninth sheet 510. The first capacitor pattern 511 is exposed on the first side surface of the filter stack 110 and is connected to the first external electrode 120.

[0118] A second capacitor pattern 512 is disposed on the upper surface of the ninth sheet 510, spaced apart from the first capacitor pattern 511. The second capacitor pattern 512 is spaced apart from the first capacitor pattern 511 and is biased toward the fourth side surface of the ninth sheet 510.

[0119] A first end portion 512a of the second capacitor pattern 512 is disposed adjacent to the center of the ninth sheet 510. A second end portion 512b of the second capacitor pattern 512 is disposed to align with the first side surface of the ninth sheet 510. The second capacitor pattern 512 is exposed on the first side surface of the filter stack 110 and is connected to the second external electrode 130.

[0120] A third capacitor pattern 513 is disposed on the upper surface of the ninth sheet 510. The third capacitor pattern 513 is spaced apart from the first capacitor pattern 511 and the second capacitor pattern 512 and is biased toward the third side surface of the ninth sheet 510. The third capacitor pattern 513 is disposed opposite to the second capacitor 512, and the first capacitor pattern 511 is disposed between the third capacitor pattern 513 and the second capacitor pattern 512.

[0121] A first end portion 513a of the third capacitor pattern 513 is disposed adjacent to the center of the ninth sheet 510. A second end portion 513b of the third capacitor pattern 513 is disposed to align with the first side surface of the ninth sheet 510. The third capacitor pattern 513 is exposed on the first side surface of the filter stack 110 and is connected to the third external electrode 140.

[0122] A fourth capacitor pattern 514 is disposed on the upper surface of the ninth sheet 510.

[0123] A first end portion 514a of the fourth capacitor pattern 514 is disposed adjacent to the center of the ninth sheet 510. The first end portion 514a of the fourth capacitor pattern 514 faces the first end portion 511a of the first capacitor pattern 511.

[0124] A second end portion 514b of the fourth capacitor pattern 514 is disposed to align with the second side surface of the ninth sheet 510. The fourth capacitor pattern 514 is exposed on the second side surface of the filter stack 110 and is connected to the fourth external electrode 150.

[0125] A fifth capacitor pattern 515 is disposed on the upper surface of the ninth sheet 510. The fifth capacitor pattern 515 is spaced apart from the fourth capacitor pattern 514 and is biased toward the third side surface of the ninth sheet 510.

[0126] The first end 515a of the fifth capacitor pattern 515 is disposed adjacent to the center of the ninth sheet 510. The first end 515a of the fifth capacitor pattern 515 faces the first end 513a of the third capacitor pattern 513.

[0127] The second end 515b of the fifth capacitor pattern 515 is arranged to be aligned with the second side surface of the ninth sheet 510. The fifth capacitor pattern 515 is exposed on the second side surface of the filter stack 110 and is connected to the fifth external electrode 160.

[0128] The sixth capacitor pattern 516 is disposed on the upper surface of the ninth sheet 510. The sixth capacitor pattern 516 is spaced apart from the fourth capacitor pattern 514 and the fifth capacitor pattern 515 and is biased toward the fourth side surface of the ninth sheet 510. The sixth capacitor pattern 516 is disposed opposite to the fifth capacitor pattern 515, and the fourth capacitor pattern 514 is interposed between the sixth capacitor pattern 516 and the fifth capacitor pattern 515.

[0129] The first end 516a of the sixth capacitor pattern 516 is disposed adjacent to the center of the ninth sheet 510. The first end 516a of the sixth capacitor pattern 516 faces the first end 512a of the second capacitor pattern 512.

[0130] The second end 516b of the sixth capacitor pattern 516 is arranged to be aligned with the second side surface of the ninth sheet 510. The sixth capacitor pattern 516 is exposed on the second side surface of the filter stack 110 and is connected to the sixth external electrode 170.

[0131] Assuming that the first to third external electrodes 120 to 140 disposed on the first side surface of the filter stack 110 are used as the input terminals of the stacked common-mode filter 100, and the third to sixth external electrodes 140 to 170 disposed on the second side surface of the filter stack 110 are used as the output terminals of the stacked common-mode filter 100.

[0132] The first to third capacitor patterns 511 to 513 are disposed on the first side surface of the filter stack 110 and are respectively connected to the first to third external electrodes 120 to 140 in a one-to-one correspondence. The fourth to sixth capacitor patterns 514 to 516 are disposed on the second side surface of the filter stack 110 and are respectively connected to the fourth to sixth external electrodes 150 to 160 in a one-to-one correspondence.

[0133] The filter stack 110 may include a ninth sheet 510 formed with first to third capacitor patterns 511 to 513 connected to an input terminal for adjusting and controlling capacitance characteristics, or may include a ninth sheet 510 formed with fourth to sixth capacitor patterns 514 to 516 connected to an output terminal.

[0134] A tenth sheet 520 is disposed below the ninth sheet 510. A floating pattern 522 for forming capacitance is disposed on the upper surface of the tenth sheet 520 together with the capacitor patterns of the ninth sheet 510.

[0135] See Figure 16 , the floating pattern 522 is formed in a plate shape and placed on the upper surface of the tenth sheet 520. The area of the floating pattern 522 is smaller than the area of the tenth sheet 520, and the outer periphery of the floating pattern 522 is spaced apart from the four side surfaces of the tenth sheet 520. The area of the floating pattern 522 is larger than the areas of a first inductor pattern 532 and a second inductor pattern 542 to be described later, and is formed to be 90% or less of the area of the tenth sheet 520.

[0136] The floating pattern 522 overlaps with the capacitor patterns of the ninth sheet 510 to form an overlapping region, and capacitance is formed in the overlapping region.

[0137] The floating pattern 522 forms a first overlapping region 522a with the first capacitor pattern 511, and a first capacitance is formed in the first overlapping region 522a. The floating pattern 522 forms a second overlapping region 522b with the second capacitor pattern 512, and a second capacitance is formed in the first overlapping region 522a. The floating pattern 522 forms a third overlapping region 522c with the third capacitor pattern 513, and a third capacitance is formed in the first overlapping region 522a. The floating pattern 522 forms a fourth overlapping region 522d with the fourth capacitor pattern 514, and a fourth capacitance is formed in the first overlapping region 522a. The floating pattern 522 forms a fifth overlapping region 522e with the fifth capacitor pattern 515, and a fifth capacitance is formed in the first overlapping region 522a. The floating pattern 522 forms a sixth overlapping region 522f with the sixth capacitor pattern 516, and a sixth capacitance is formed in the first overlapping region 522a.

[0138] Accordingly, the floating pattern 522 forms capacitance with the capacitor patterns. Therefore, the stacked common-mode filter 100 can expand the attenuation band by forming an additional depression in the common-mode attenuation characteristic. That is, the stacked common-mode filter 100 can achieve broadband characteristics together with the poles formed by the coil patterns of the filter stack 110 by forming additional poles due to the floating pattern 522 and the capacitor patterns.

[0139] The eleventh sheet 530 is disposed below the tenth sheet 520. The first inductor pattern 532 is located on the upper surface of the eleventh sheet 530.

[0140] For example, referring to Figure 17 , the first inductor pattern 532 is wound around the upper surface of the eleventh sheet 530, thereby forming a seventh annular structure. The first inductor pattern 532 is wound around a virtual winding axis passing through the center of the eleventh sheet 530 to form a seventh annular structure.

[0141] The first end 532a of the first inductor pattern 532 is disposed in the inner peripheral region of the seventh annular structure and is located at the center of the eleventh sheet 530. The first end 532a of the first inductor pattern 532 is connected to the floating pattern 522 of the tenth sheet through a via.

[0142] The second end 532b of the first inductor pattern 532 is disposed in the outer peripheral region of the seventh annular structure.

[0143] The twelfth sheet 540 is located below the eleventh sheet 530, and the second inductor pattern 542 is located on the upper surface of the twelfth sheet 540.

[0144] For example, referring to Figure 18 , the second inductor pattern 542 is wound around the upper surface of the twelfth sheet 540, thereby forming an eighth annular structure. The second inductor pattern 542 is wound around a virtual winding axis passing through the center of the twelfth sheet 540 to form an eighth annular structure.

[0145] The first end 542a of the second inductor pattern 542 is located in the inner peripheral region of the eighth annular structure and is located at the center of the twelfth sheet 540. The first end 542a of the second inductor pattern 542 is connected to the ground pattern 555 of the thirteenth sheet 510 through a via passing through the twelfth sheet 540.

[0146] The second end 542b of the second inductor pattern 542 is located in the outer peripheral region of the eighth annular structure. The first end 542b of the second inductor pattern 542 is connected to the first inductor pattern 532 of the eleventh sheet 530 through a via. The second end 542b of the second inductor pattern 542 is connected to the second end 532b of the first inductor pattern 532 through a via.

[0147] Since the second end 532b of the first inductor pattern 532 and the second end 542b of the second inductor pattern 542 are connected through a via, the first inductor pattern 532 and the second inductor pattern 542 constitute a parallel common inductor, and the parallel common inductor forms a preset inductance.

[0148] Referring to Figure 19, the lengths (areas) of the first inductor pattern 532 and the second inductor pattern 542 can be varied according to the desired sub-resonant frequency.

[0149] As the lengths of the first inductor pattern 532 and the second inductor pattern 542 increase, the inductance value increases, and the sub-resonant frequency shifts to a lower frequency. As the lengths of the first inductor pattern 532 and the second inductor pattern 542 decrease, the inductance value decreases, and the sub-resonant frequency shifts to a higher frequency.

[0150] Therefore, the lengths of the first inductor pattern 532 and the second inductor pattern 542 are determined based on the desired sub-resonant frequency. The first inductor pattern 532 and the second inductor pattern 542 can be formed to have the same length or different lengths.

[0151] The thirteenth sheet 510 is disposed below the twelfth sheet 540. The ground pattern 555 is formed in the thirteenth sheet 510.

[0152] The ground pattern 555 is connected to the inductor patterns 532 and 542, and reduces the influence of the stray capacitance formed between the stacked common-mode filter 100 and the printed circuit board.

[0153] For example, referring to Figure 20 , the ground pattern 555 is formed on the upper surface of the thirteenth sheet 510. The ground pattern 555 includes a first ground pattern 555a, a second ground pattern 555b, and a third ground pattern 555c.

[0154] The first ground pattern 555a is formed in a plate shape and is located at the center of the upper surface of the thirteenth sheet 510. The area of the first ground pattern 555a is smaller than the area of the thirteenth sheet 510, and is arranged such that the outer periphery of the first ground pattern 555a is spaced apart from the four side surfaces of the thirteenth sheet 510. The first ground pattern 555a is connected to the first end 542a of the second inductor pattern 542 through a via hole passing through the twelfth sheet 540.

[0155] The second ground pattern 555b extends from the third side of the first ground pattern 555a and is arranged to be aligned with the third side of the thirteenth sheet 510. The first end of the second ground pattern 555b is connected to the third side of the first ground pattern 555a. The second end of the second ground pattern 555b is arranged to be aligned with the third side of the thirteenth sheet 510 and is connected to the seventh outer electrode 180.

[0156] The third ground pattern 555c extends from the fourth side of the first ground pattern 555a and is arranged to align with the fourth side of the thirteenth sheet 510. The first end of the third ground pattern 555c is connected to the fourth side of the first ground pattern 555a. The second end of the third ground pattern 555c is arranged to align with the fourth side of the thirteenth sheet 510 and is connected to the eighth outer electrode 190.

[0157] Therefore, the ground pattern 555 is exposed to the third and fourth side surfaces of the filter stack 110, thereby forming a ground connection to the seventh outer electrode 180 and the eighth outer electrode 190.

[0158] The first outer electrode 120 is located on the first side surface of the filter stack 110. Opposite ends of the first outer electrode 120 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0159] The first outer electrode 120 is connected to the first terminal pattern 212, the fourth terminal pattern 344, and the first capacitor pattern 511 that are exposed to the first side surface of the filter stack 110. In this case, the first outer electrode 120 is connected to the second end 212b of the first terminal pattern 212, the second end 344b of the fourth terminal pattern 344, and the second end 511b of the first capacitor pattern 511a.

[0160] The second outer electrode 130 is located on the first side surface of the filter stack 110. The second outer electrode 130 is arranged to be biased towards the fourth side surface of the filter stack 110 and is spaced apart from the first outer electrode 120. Opposite ends of the second outer electrode 130 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0161] The second outer electrode 130 is connected to the third terminal pattern 342 and the second capacitor pattern 512 that are exposed to the first side surface of the filter stack 110. The second outer electrode 130 is connected to the second end 342b of the third terminal pattern 342 and the second end 512b of the second capacitor pattern 512.

[0162] The third outer electrode 140 is located on the first side surface of the filter stack 110. The third outer electrode 140 is arranged to be biased towards the third side surface of the filter stack 110 and is spaced apart from the first outer electrode 120. The third outer electrode 140 is opposite to the second outer electrode 130, and the first outer electrode 120 is between the third outer electrode 140 and the second outer electrode 130. Opposite ends of the third outer electrode 140 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0163] The third external electrode 140 is connected to the second terminal pattern 214 and the third capacitor pattern 513 that are exposed on the first side surface of the filter stack 110. The third external electrode 140 is connected to the second end 214b of the second terminal pattern 214 and the second end 513b of the third capacitor pattern 513.

[0164] The fourth external electrode 150 is located on the second side surface of the filter stack 110. The fourth external electrode 150 is opposite to the first external electrode 120, with the filter stack 110 interposed therebetween, and the fourth external electrode 150 is arranged to face the first external electrode 120. Opposite ends of the fourth external electrode 150 may be formed to extend to the upper surface and the lower surface of the filter stack 110.

[0165] The fourth external electrode 150 is connected to the first coil pattern 222, the sixth coil pattern 332, and the fourth capacitor pattern 514 that are exposed on the second side surface of the filter stack 110. The fourth external electrode 150 is connected to the second end 222b of the first coil pattern 222, the second end 332b of the sixth coil pattern 332, and the second end 514b of the fourth capacitor pattern 514.

[0166] The fifth external electrode 160 is located on the second side surface of the filter stack 110. The fifth external electrode 160 is opposite to the third external electrode 140, with the filter stack 110 interposed therebetween, and the fifth external electrode 160 is arranged to face the third external electrode 140. The fifth external electrode 160 is arranged to be biased toward the third side surface of the filter stack 110 and is spaced apart from the fourth external electrode 150. Opposite ends of the fifth external electrode 160 may be formed to extend to the upper surface and the lower surface of the filter stack 110.

[0167] The fifth external electrode 160 is connected to the second coil pattern 232, the third coil pattern 242, and the fifth capacitor pattern 515 that are exposed on the second side surface of the filter stack 110. The fifth external electrode 160 is connected to the second end 232b of the second coil pattern 232, the second end 242b of the third coil pattern 242, and the second end 515b of the fifth capacitor pattern 515.

[0168] The sixth external electrode 170 is located on the second side surface of the filter stack 110. The sixth external electrode 170 is opposite to the second external electrode 130, the filter stack 110 is interposed between the sixth external electrode 170 and the second external electrode 130, and the sixth external electrode 170 is arranged to face the second external electrode 130. The sixth external electrode 170 is arranged to be biased towards the fourth side surface of the filter stack 110 and is spaced apart from the fourth external electrode 150. The sixth external electrode 170 is opposite to the fifth external electrode 160, and the fourth external electrode 150 is interposed between the sixth external electrode 170 and the fifth external electrode 160. Opposite ends of the sixth external electrode 170 may be formed to extend to the upper surface and the lower surface of the filter stack 110.

[0169] The sixth external electrode 170 is connected to a fourth coil pattern 312, a fifth coil pattern 322, and a sixth capacitor pattern 516 that are exposed on the second side surface of the filter stack 110. The sixth external electrode 170 is connected to a second end portion 312b of the fourth coil pattern 312, a second end portion 322b of the fifth coil pattern 322, and a second end portion 516b of the sixth capacitor pattern 516.

[0170] The seventh external electrode 180 is located on the third side surface of the filter stack 110. The seventh external electrode 180 is connected to a ground pattern 555 that is exposed on the third side surface of the filter stack 110. The seventh external electrode 180 is connected to a second end portion of a second ground pattern 555b that is exposed on the third side surface of the filter stack 110. Opposite ends of the seventh external electrode 180 may be formed to extend to the upper surface and the lower surface of the filter stack 110.

[0171] The eighth external electrode 190 is located on the fourth side surface of the filter stack 110. The eighth external electrode 190 is opposite to the eighth external electrode 190, and the filter stack 110 is interposed between the eighth external electrode 190 and the eighth external electrode 190. The eighth external electrode 190 is connected to the ground pattern 555 that is exposed on the third side surface of the filter stack 110. The eighth external electrode 190 is connected to a second end portion of a third ground pattern 555c that is exposed on the fourth side surface of the filter stack 110. Opposite ends of the eighth external electrode 190 may be formed to extend to the upper surface and the lower surface of the filter stack 110.

[0172] The first outer electrode 120 and the fourth outer electrode 150 serve as the input terminal and the output terminal of the first channel formed by the first coil pattern 222 and the sixth coil pattern 332. The third outer electrode 140 and the fifth outer electrode 160 serve as the input terminal and the output terminal of the second channel formed by the second coil pattern 232 and the third coil pattern 242. The second outer electrode 130 and the sixth outer electrode 170 serve as the input terminal and the output terminal of the third channel formed by the fourth coil pattern 312 and the fifth coil pattern 322. The seventh outer electrode 180 and the seventh outer electrode 180 are connected to the ground pattern 555, thereby functioning as a ground terminal.

[0173] Figure 21 An equivalent circuit of the stacked common mode filter 100 according to an embodiment of the present invention is shown, and capacitors are formed between the first coil and the second coil, between the second coil and the third coil, and between the first coil and the third coil.

[0174] The filter stack 110 is formed by stacking the first stack 20 and the second stack 300 having coil patterns to form a coil stack 400, and placing a third stack 500 including capacitor patterns, a floating pattern 522, and inductor patterns 532 and 542 below the coil stack 400. Therefore, the capacitor patterns connected between the coils and the outer electrodes of each channel are interconnected, and a coupling effect is generated between the capacitor patterns and the floating pattern 522. As a result, additional capacitors C1 to C6 are formed between the coils and the outer electrodes of each channel due to the capacitor patterns and the floating pattern 522.

[0175] Therefore, the stacked common mode filter 100 according to an embodiment of the present invention can increase the capacitance without adding an electrode layer including a coil pattern or increasing the area of the coil pattern, thereby achieving a larger capacitance while maintaining the same size compared to the existing stacked common mode filter 10.

[0176] In addition, in the stacked common mode filter 100 according to an embodiment of the present invention, since an additional capacitor is formed between the capacitor pattern and the floating pattern 522, an additional depression can be formed in the common mode attenuation characteristic, thereby expanding the attenuation band.

[0177] The first inductor pattern 532 and the second inductor pattern 542 form a single inductance. Opposite ends of the inductor patterns 532 and 542 formed by the first inductor pattern 532 and the second inductor pattern 542 are respectively connected to the floating pattern 522 and the ground pattern 555, and a short - circuit circuit is formed between the floating pattern 522 and the ground pattern 555.

[0178] The inductance of the inductor patterns 532 and 542 formed by the first inductor pattern 532 and the second inductor pattern 542 can be defined by the lengths of the first inductor pattern 532 and the second inductor pattern 542. The inductance of the inductor patterns 532 and 542 formed by the first inductor pattern 532 and the second inductor pattern 542 is the dominant factor in adjusting and controlling the sub-resonant frequency of the stacked common-mode filter 100.

[0179] The main resonant frequency is determined by the capacitance formed between the first coil, the second coil, and the third coil. The sub-resonant frequency is determined by the capacitor patterns 511 to 516, the floating pattern 522, and the inductor patterns 532 and 542.

[0180] Here, compared with the capacitance formed between the capacitor patterns 511 to 516 and the floating pattern 522, the inductor patterns 532 and 542 have a relatively high inductance value, and thus become the main factor in determining the sub-resonant frequency.

[0181] The inductor patterns 532 and 542 have a numerical adjustment range that allows the sub-resonant frequency to be adjusted to various values within the same area, and since they have a smaller area compared to the capacitor patterns 511 to 516, the design flexibility can be improved. Compared with the inductor patterns 532 and 542, the capacitor patterns 511 to 516 and the floating pattern 522 form a relatively small capacitance, thereby reducing the loss during signal transmission.

[0182] Thus, the inductor patterns 532 and 542 are the dominant factors in determining the sub-resonant frequency, and the influence of the parasitic inductance (parasitic L) that varies according to the mounting direction of the chip can be reduced, thereby preventing characteristic deviation due to the mounting direction.

[0183] See Figure 22 , assuming that the first stacked common-mode filter 100a has the first inductor pattern 532 and the second inductor pattern 542 formed with a first length, the second stacked common-mode filter 100b has the first inductor pattern 532 and the second inductor pattern 542 formed with a second length, and the third stacked common-mode filter 100c has the first inductor pattern 532 and the second inductor pattern 542 formed with a third length. The first length is shorter than the second length, and the second length is shorter than the third length.

[0184] See Figure 23 , based on the common mode, the first stacked common-mode filter 100a (A), the second stacked common-mode filter 100b (B), and the third stacked common-mode filter 100c (C) form a first resonant frequency RF1 at approximately 2.45 GHz. The first resonant frequency RF1 of the first stacked common-mode filter to the third stacked common-mode filter 100a (A) to 100c (C) can be regarded as the same within the error range.

[0185] On the other hand, the first stacked common-mode filter to the third stacked common-mode filters 100a to 100c form different second resonance frequencies RF2-1 to RF2-3 in common mode. In other words, the first stacked common-mode filter 100a (see A) forms a second resonance frequency RF2-1 at about 4.8 GHz, the second stacked common-mode filter 100b (see B) forms a second resonance frequency RF2-2 at about 4.5 GHz, and the third stacked common-mode filter 100c (see C) forms a second resonance frequency RF2-3 at about 4.2 GHz.

[0186] That is to say, as the length of the inductor patterns (i.e., the first inductor pattern 532 and the second inductor pattern 542) increases, the inductance increases, and the second resonance frequency of the stacked common-mode filter 100 shifts to a lower frequency. As the length of the inductor patterns (i.e., the first inductor pattern 532 and the second inductor pattern 542) decreases, the inductance decreases, and the second resonance frequency of the stacked common-mode filter 100 shifts to a higher frequency.

[0187] See Figure 24 , based on differential mode, the first stacked common-mode filter to the third stacked common-mode filters 100a to 100c generate cutoffs at about 7.1 GHz, 7.2 GHz, 7.37 GHz, and 7.53 GHz. The cutoff frequencies of the first stacked common-mode filter to the third stacked common-mode filters 100a to 100c can be regarded as the same within the error range.

[0188] It can be seen therefrom that the length of the inductor patterns 532, 542 is the dominant factor for adjusting (controlling) the second resonance frequency of the stacked common-mode filter 100. By adjusting the length of the first inductor pattern 532 and / or the length of the second inductor pattern 542, the second resonance frequency characteristic of the stacked common-mode filter 100 can be changed.

[0189] In addition, in the stacked common-mode filter 100 according to an embodiment of the present invention, by placing (arranging) the third stacked body 500 including the inductor patterns 532, 542 below the coil stacked body 400, a short-circuit circuit is formed, so that the second resonance frequency can be easily adjusted / controlled by adjusting the length of the inductor patterns 532, 542.

[0190] See Figure 25 , the filter stacked body 110 may further include a first magnetic sheet 620 provided on the upper part of the first stacked body 200, and a second magnetic sheet 640 interposed between the second stacked body 300 and the third stacked body 500. Here, as an example, the first magnetic sheet 620 and the second magnetic sheet 640 are sheets formed of a magnetic material such as ferrite.

[0191] See Figure 26, the filter stack 110 may further include a third magnetic sheet 660 disposed below the third stack 500. Here, as an example, the third magnetic sheet 660 is a sheet formed of a magnetic material such as ferrite. The ferrite may include Ni-Zn or Mn-Zn.

[0192] The third magnetic sheet 660 can increase the parallel inductance caused by the inductor patterns 532 and 542. Adding the third magnetic sheet 660 to the lowermost part of the same multilayer structure makes the stacked common-mode filter 100 have a lower sub-resonant frequency.

[0193] In the stacked common-mode filter 100 according to an embodiment of the present invention, the interval between the first resonant frequency and the second resonant frequency can be adjusted according to the presence or absence of the third magnetic sheet 660 disposed at the lowermost part of the filter stack 110. Here, placing the third magnetic sheet 660 can reduce (or result in a narrower) interval between the first resonant frequency and the second resonant frequency in the stacked common-mode filter 100.

[0194] See Figure 27 , the first stacked common-mode filter 100a does not include the third magnetic sheet 660, and the inductor patterns 532 and 542 are formed to have a first length. The second stacked common-mode filter 100b does not include the third magnetic sheet 660, and the inductor patterns 532 and 542 are formed to have a second length longer than the first length. The third stacked common-mode filter 100c includes the third magnetic sheet 660, and the inductor patterns 532 and 542 are formed to have a first length. The fourth stacked common-mode filter 100 includes the third magnetic sheet 660, and the inductor patterns 532 and 542 are formed to have a second length longer than the first length.

[0195] See Figure 28 , the first stacked common-mode filter 100a has a first resonant frequency of about 2.35 GHz and a second resonant frequency of about 4.97 GHz. The second stacked common-mode filter 100b has a first resonant frequency of about 2.38 GHz and a second resonant frequency of about 4.37 GHz. The third stacked common-mode filter 100c has a first resonant frequency of about 2.45 GHz and a second resonant frequency of about 4.8 GHz. The fourth stacked common-mode filter 100 has a first resonant frequency of about 2.50 GHz and a second resonant frequency of about 4.21 GHz.

[0196] The interval G1 between the first resonance frequency and the second resonance frequency of the first stacked common-mode filter 100a is approximately 2.62 GHz. The interval G2 between the first resonance frequency and the second resonance frequency of the second stacked common-mode filter 100b is approximately 1.99 GHz. The interval G3 between the first resonance frequency and the second resonance frequency of the third stacked common-mode filter 100c is approximately 2.35 GHz. The interval G4 between the first resonance frequency and the second resonance frequency of the fourth stacked common-mode filter 100 is approximately 1.71 GHz.

[0197] When comparing the first stacked common-mode filter 100a and the third stacked common-mode filter 100c with inductor patterns 532 and 542 of the same length, the interval G3 of the third stacked common-mode filter 100c including the third magnetic sheet 660 is reduced by approximately 0.27 GHz compared to the interval G1 of the first stacked common-mode filter 100a without the third magnetic sheet 660.

[0198] When comparing the second stacked common-mode filter 100b and the fourth stacked common-mode filter 100 with inductor patterns 532 and 542 of the same length, the interval G4 of the fourth stacked common-mode filter 100 including the third magnetic sheet 660 is reduced by approximately 0.28 GHz compared to the interval G2 of the second stacked common-mode filter 100b without the third magnetic sheet 660.

[0199] Therefore, in the stacked common-mode filter 100 according to an embodiment of the present invention, the interval between the first resonance frequency and the second resonance frequency can be adjusted (controlled) by using the third magnetic sheet 660 provided at the lowermost part of the filter stack 110.

[0200] See Figure 29 , different from the existing stacked common-mode filter having a structure in which a coil stack 12 and a capacitor stack 13 are stacked (i.e., an LC filter structure), the stacked common-mode filter 100 according to an embodiment of the present invention has a structure in which a third stack 500 of capacitors and inductors is located below the coil stack 400 (i.e., an LPF filter structure). Therefore, compared with the existing stacked common-mode filter 10, the stacked common-mode filter 100 according to an embodiment of the present invention has improved attenuation characteristics in common mode and insertion loss and cut-off characteristics in differential mode.

[0201] See Figure 30 , the existing stacked common-mode filter (see C) forms three resonance frequencies, where the first resonance frequency is formed at approximately 2.5 GHz, the second resonance frequency is formed at approximately 5.2 GHz, and the third resonance frequency is formed at approximately 7.3 GHz.

[0202] The stacked common-mode filter 100 (see D) according to an embodiment of the present invention forms two resonant frequencies, where the first resonant frequency is formed at approximately 2.5 GHz and the second resonant frequency is formed at approximately 5.5 GHz.

[0203] It can be seen that the attenuation performance of the stacked common-mode filter 100 according to an embodiment of the present invention is only concentrated in the common-mode attenuation frequency band (i.e., the target frequency band), indicating that the attenuation characteristics under common mode are improved compared with those of the existing stacked common-mode filter 10.

[0204] See Figure 31 , the stacked common-mode filter 100 (see E) according to an embodiment of the present invention has improved low-frequency cut-off characteristics and reduced ripple in the differential mode compared with the existing stacked common-mode filter (see F).

[0205] The above description is only an explanation of the technical idea of the present invention. Those skilled in the art can make various changes and deformations to the present invention without departing from the essential characteristics of the present invention. Therefore, the embodiments of the present invention should not be understood as limiting the technical idea of the present invention, but as an illustration of the technical idea of the present invention. The technical idea of the present invention is not limited by the embodiments. The protection scope of the present invention should be interpreted based on the claims, and all technical ideas within the equivalent scope of the present invention should be understood to be covered within the scope of the claims of the present invention.

Claims

1. A stacked common mode filter, characterized in that, it includes: A first stack body provided with a first coil pattern, a second coil pattern, and a third coil pattern; A second stack body provided with a fourth coil pattern, a fifth coil pattern, and a sixth coil pattern and disposed below the first stack body; And A third stack body disposed below the second stack body, The third stack body includes: A plurality of capacitor patterns disposed below the second stack body; A floating pattern disposed below the plurality of capacitor patterns and forming an additional capacitance by overlapping with the plurality of capacitor patterns; A ground pattern disposed below the floating pattern; and An inductor pattern disposed between the floating pattern and the ground pattern, A first end of the inductor pattern is connected to the floating pattern, and a second end of the inductor pattern is connected to the ground pattern.

2. The stacked common mode filter according to claim 1, characterized in that, The first stack body and the second stack body form a coil stack body, The coil stack body is arranged such that the first coil pattern, the second coil pattern, the third coil pattern, the fourth coil pattern, the fifth coil pattern, and the sixth coil pattern are stacked in sequence, The first coil pattern and the sixth coil pattern form a first coil, and the first coil forms a first channel, The second coil pattern and the third coil pattern are between the first coil pattern and the sixth coil pattern and form a second coil, and the second coil forms a second channel, The fourth coil pattern and the fifth coil pattern are between the third coil pattern and the sixth coil pattern and form a third coil, and the third coil forms a third channel.

3. The stacked common mode filter according to claim 1, characterized in that, The first stack body includes: A first thin sheet; A first terminal pattern located on a first surface of the first thin sheet; A second terminal pattern located on the first surface of the first thin sheet and spaced apart from the first terminal pattern; A second thin sheet disposed below the first thin sheet; The first coil pattern forms a first annular structure wound around a first surface of the second thin sheet, including a first end located in an inner peripheral region of the first annular structure and connected to the first terminal pattern through a via passing through the first thin sheet, and a second end located in an outer peripheral region of the first annular structure; A third thin sheet located below the second thin sheet; The second coil pattern forms a second annular structure wound around a first surface of the third thin sheet, including a first end located in an inner peripheral region of the second annular structure and connected to the second terminal pattern through vias passing through the first thin sheet and the second thin sheet, and a second end located in an outer peripheral region of the second annular structure; A fourth thin sheet located below the third thin sheet; and The third coil pattern forms a third annular structure wound around the first surface of the fourth sheet, and includes a first end located in the inner peripheral region of the third annular structure and connected to the second end of the second coil pattern through a via hole passing through the third sheet, and a second end located in the outer peripheral region of the third annular structure.

4. The stacked common mode filter according to claim 1, wherein, the second stack includes: a fifth sheet; the fourth coil pattern forms a fourth annular structure wound around the first surface of the fifth sheet, and includes a first end located in the inner peripheral region of the fourth annular structure and a second end located in the outer peripheral region of the fourth annular structure; a sixth sheet disposed below the fifth sheet; the fifth coil pattern forms a fifth annular structure wound around the first surface of the sixth sheet, and includes a first end located in the inner peripheral region of the fifth annular structure and connected to the first end of the fourth coil pattern through a via hole passing through the fifth sheet, and a second end located in the outer peripheral region of the fifth annular structure; a seventh sheet disposed below the sixth sheet; the sixth coil pattern forms a sixth annular structure wound around the first surface of the seventh sheet, and includes a first end located in the inner peripheral region of the sixth annular structure and a second end located in the outer peripheral region of the sixth annular structure; an eighth sheet disposed below the seventh sheet; a third terminal pattern located on the first surface of the seventh sheet, and includes a first end connected to the first end of the fourth coil pattern and the first end of the fifth coil pattern through via holes passing through the fifth sheet, the sixth sheet, and the seventh sheet; and a fourth terminal pattern located on the first surface of the seventh sheet and spaced apart from the third terminal pattern, and includes a first end connected to the first end of the sixth coil pattern through a via hole passing through the seventh sheet.

5. The stacked common mode filter according to claim 1, wherein, the third stack includes: a ninth sheet; a plurality of capacitor patterns located on the first surface of the ninth sheet and spaced apart from each other; a tenth sheet located below the ninth sheet; and a floating pattern located on the first surface of the tenth sheet, forming a plurality of overlapping regions by overlapping with the plurality of capacitor patterns, and configured to form additional capacitance in the plurality of overlapping regions.

6. The stacked common mode filter according to claim 5, wherein, the third stack further includes: a ground pattern located below the tenth sheet; and an inductor pattern interposed between the tenth sheet and the ground pattern, and includes a first end connected to the floating pattern and a second end connected to the ground pattern.

7. The stacked common mode filter according to claim 6, wherein, the third stack further includes: an eleventh sheet interposed between the tenth sheet and the ground pattern; and The twelfth thin sheet, which is interposed between the eleventh thin sheet and the ground pattern, The inductor pattern includes: A first inductor pattern, which is located on the first surface of the eleventh thin sheet, includes a first end connected to the floating pattern through a via hole passing through the tenth thin sheet, and a second end spaced apart from the first end; and A second inductor pattern, which is located on the first surface of the twelfth thin sheet, includes a first end connected to the ground pattern, and a second end connected to the second end of the first inductor pattern through a via hole passing through the eleventh thin sheet.

8. The stacked common mode filter according to claim 1, characterized in that, further comprising: A first magnetic sheet, which is disposed above the first stacked body; and A second magnetic sheet, which is interposed between the second stacked body and the third stacked body.

9. The stacked common mode filter according to claim 1, characterized in that, further comprising a third magnetic sheet disposed below the third stacked body.

10. The stacked common mode filter according to claim 1, characterized in that, The filter stacked body formed by stacking the first stacked body, the second stacked body and the third stacked body has a first resonance frequency and a second resonance frequency higher than the first resonance frequency, As the length of the inductor pattern increases, the second resonance frequency shifts to a higher frequency.

11. The stacked common mode filter according to claim 1, characterized in that, The filter stacked body formed by stacking the first stacked body, the second stacked body and the third stacked body has a first resonance frequency and a second resonance frequency higher than the first resonance frequency, As the length of the inductor pattern decreases, the second resonance frequency shifts to a lower frequency.

12. The stacked common mode filter according to claim 1, characterized in that, The filter stacked body formed by stacking the first stacked body, the second stacked body and the third stacked body includes a first side surface, a second side surface opposite to the first side surface, a third side surface and a fourth side surface opposite to the third side surface, The stacked common mode filter further comprises: A first external electrode, which is disposed on the first side surface and is connected to the second end of the first terminal pattern, the second end of the fourth terminal pattern and the second end of the first capacitor pattern exposed on the first side surface; A second external electrode, which is disposed on the first side surface and is connected to the second end of the third terminal pattern and the second end of the second capacitor pattern exposed on the first side surface; A third external electrode, which is disposed on the first side surface and is connected to the second end of the second terminal pattern and the second end of the third capacitor pattern exposed on the first side surface; A fourth external electrode, which is disposed on the second side surface and is connected to the second end of the first coil pattern, the second end of the sixth coil pattern and the second end of the fourth capacitor pattern exposed on the second side surface; A fifth external electrode, which is disposed on the second side surface and is connected to a second end of the second coil pattern, a second end of the third coil pattern, and a second end of a fifth capacitor pattern that are exposed on the second side surface; and A sixth external electrode, which is disposed on the second side surface and is connected to a second end of the fourth coil pattern, a second end of the fifth coil pattern, and a second end of a sixth capacitor pattern that are exposed on the second side surface.

13. The stacked common mode filter according to claim 12, wherein it further comprises: A seventh external electrode, which is disposed on the third side surface and is connected to a first end of a ground pattern that is exposed on the third side surface; and An eighth external electrode, which is disposed on the fourth side surface and is connected to a twenty-first end of the ground pattern that is exposed on the fourth side surface.

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