Laminated common mode filter

Abstract

The laminated common mode filter of the present invention has a filter stack including: a coil stack including a plurality of coils forming different channels; and a stack stacked under the coil stack and having a capacitor pattern, a floating pattern, an inductor pattern, and a ground pattern. Wherein a resonant frequency characteristic may vary according to the inductor pattern.

Description

Technical field

[0001] The present invention relates to a laminated common mode filter that allows differential signal current to pass through and removes common mode noise current in electronic equipment used in high-speed signal lines. [Background Technology]

[0002] Mobile terminals typically use the Mobile Industry Processor Interface (MIPI) D-PHY standard for digital data transmission. The MIPI D-PHY standard connects the main circuit of a mobile terminal to a display or camera, using differential signaling over two transmission lines to transmit data.

[0003] As the amount of data transmitted and received in mobile terminals increases rapidly, the mobile terminals require a transmission method capable of transmitting and receiving data at a speed faster than the MIPID-PHY standard.

[0004] Therefore, the mobile terminal industry has recently begun research on applying the MIPI C-PHY standard to mobile terminals. The MIPI C-PHY standard uses three transmission lines, transmitting different voltages from the transmitter to each transmission line, and then generating differential outputs at the receiver by taking the difference between the lines.

[0005] The contents described in the background technology are intended to help understand the background of the present invention and may contain contents that are not disclosed in the prior art. [Summary of the invention]

[0006] The present invention is proposed in view of the above situation, and the purpose of the present invention is to provide a laminated common mode filter, wherein a stacked body including a capacitor pattern, a floating pattern, an inductor pattern and a ground pattern is arranged under the filter stacked body, so that characteristics such as the resonance point (resonance frequency) and cutoff can be controlled.

[0007] In addition, another object of the present invention is to provide a laminated common mode filter, wherein a plurality of conducting conductors including via holes connecting coil patterns are arranged without overlapping each other, thereby preventing defects in the stacking process and adjusting the filter characteristics.

[0008] To achieve the above objectives, a laminated common mode filter according to one embodiment of the present invention may include: a first stack having a plurality of coil patterns; a second stack having a plurality of coil patterns 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 overlapping with the plurality of capacitor patterns to form additional capacitance; 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 first stack, the second stack, and the third stack may all be low-temperature co-fired ceramic stacks.

[0010] The first stack may include a first coil pattern, a second coil pattern, and a third coil pattern. The second stack may include a fourth coil pattern, a fifth coil pattern, and a sixth coil pattern. The first stack and the second stack constitute a coil stack, wherein 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 can form a first coil, and the first coil forms a first channel. The second coil pattern and the third coil pattern can be interposed between the first coil pattern and the sixth coil pattern to form a second coil, and the second coil forms a second channel. The fourth coil pattern and the fifth coil pattern can be interposed between the third coil pattern and the sixth coil pattern to form a third coil, and the third coil forms a third channel.

[0011] The first stack may include: a first sheet; a first terminal pattern, which is arranged on a first surface of the first sheet; a second terminal pattern, which is arranged on the first surface of the first sheet and is spaced apart from the first terminal pattern; a second sheet, which is arranged below the first sheet; a first coil pattern, which is wound on the first surface of the second sheet to form a rectangular first annular structure, the first coil pattern including a first end portion located in an inner peripheral area of the first annular structure and connected to the first terminal pattern through a via hole passing through the first sheet, and a second end portion located in an outer peripheral area of the first annular structure; a third sheet, which is arranged below the second sheet; a second coil pattern, which is wound on the third sheet a second rectangular ring structure wound on the first surface of the fourth sheet, the second coil pattern including a first end located in the inner peripheral area of the second ring structure and connected to the second terminal pattern through a via passing through the first sheet and the second sheet, and a second end located in the outer peripheral area of the second ring structure; a fourth sheet, which is arranged below the third sheet; and a third coil pattern, which is wound on the first surface of the fourth sheet to form a third rectangular ring structure, the third coil pattern including a first end located in the inner peripheral area of the third ring structure and connected to the second end of the second coil pattern through a via passing through the third sheet, and a second end located in the outer peripheral area of the third ring structure.

[0012] The second stack may include: a fifth sheet; a fourth coil pattern, which is wound on the first surface of the fifth sheet to form a rectangular fourth annular structure, the fourth coil pattern including a first end located in the inner peripheral area of the fourth annular structure, and a second end located in the outer peripheral area of the fourth annular structure; a sixth sheet, which is arranged below the fifth sheet; a fifth coil pattern, which is wound on the first surface of the sixth sheet to form a rectangular fifth annular structure, the fifth coil pattern including a first end located in the inner peripheral area 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 peripheral area of the fifth annular structure; a seventh sheet, which is arranged below the sixth sheet; a sixth coil pattern; and , which is wound on the first surface of the seventh sheet to form a sixth annular structure, the sixth coil pattern including a first end located in the inner peripheral area of the sixth annular structure, and a second end located in the outer peripheral area of the sixth annular structure; an eighth sheet, which is arranged below the seventh sheet; a third terminal pattern, which is located on the first surface of the seventh sheet, including a first end connected to the first end of the fourth coil pattern and the first end of the fifth coil pattern through a via hole passing through the fifth sheet, the sixth sheet and the seventh sheet, and a fourth terminal pattern, which is located on the first surface of the seventh sheet and is spaced apart from the third terminal pattern, including a first end connected to the first end of the sixth coil pattern through a via hole passing through the seventh sheet.

[0013] The third stack may include: a ninth thin sheet; a plurality of capacitor patterns located on a first surface of the ninth thin sheet and spaced apart from each other; a tenth thin sheet located below the ninth thin sheet; a floating pattern located on a first surface of the tenth thin sheet, forming a plurality of overlapping areas by overlapping with the plurality of capacitor patterns, and configured to form additional capacitance in the plurality of overlapping areas; an eleventh thin sheet located below the tenth thin sheet; an inductor pattern wound on the first surface of the tenth thin sheet to form a seventh annular structure, the inductor pattern including an inner peripheral area located in the seventh annular structure and connected to a first end of the floating pattern; a twelfth thin sheet located below the eleventh thin sheet; and a grounding pattern located on the first surface of the twelfth thin sheet and connected to a second end of the inductor pattern.

[0014] The inductor pattern may include a first region overlapping the ground pattern, and a second region not overlapping the ground pattern.

[0015] The filter stack formed by stacking the first stack, the second stack, and the third stack may have a first resonant frequency and a second resonant frequency higher than the first resonant frequency. The second resonant frequency may shift toward a higher frequency as the length of the inductor pattern increases, and may shift toward a lower frequency as the length of the inductor pattern decreases.

[0016] The filter stack formed by stacking the first stack, the second stack and the third stack may include: 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 according to an embodiment of the present invention may also include: a first external electrode, which is arranged on the first side surface and connected to the second end of the first coil pattern, the second end of the sixth coil pattern and the third end of the first capacitor pattern exposed to the first side; a second external electrode, which is arranged on the first side surface and connected to the second end of the second coil pattern, the second end of the third coil pattern and the second end of the second capacitor pattern exposed to the first side; a third external electrode, which is arranged on the first side surface and connected to the second end of the fourth coil pattern, the second end of the fifth coil pattern and the second end of the third capacitor pattern exposed to the first side; a fourth external electrode, which is arranged on the second side surface and connected to the connected to the second end of the first terminal pattern, the second end of the fourth terminal pattern and the second end of the fourth capacitor pattern exposed to the second side surface; a fifth external electrode, which is arranged on the second side surface and connected to the second end of the third terminal pattern and the second end of the fifth capacitor pattern exposed to the second side surface; a sixth external electrode, which is arranged on the second side surface and connected to the second end of the second terminal pattern and the second end of the sixth capacitor pattern exposed to the second side surface; a seventh external electrode, which is arranged on the third side surface and connected to the first end of the ground pattern exposed to the third side surface; and an eighth external electrode, which is arranged on the fourth side surface and connected to the second end of the ground pattern exposed to the fourth side surface.

[0017] [Beneficial effects of the invention]

[0018] According to the present invention, the laminated common mode filter allows the distance (pitch) between the coil patterns forming each channel to be kept constant, thereby making the resistance and inductance of the coil patterns forming each channel uniform.

[0019] Furthermore, the laminated common mode filter has the effect of minimizing variations in the inductance characteristics and common mode attenuation characteristics of the coil pattern by providing terminal patterns for connection to external electrodes at the uppermost and lowermost portions of the filter stack.

[0020] Furthermore, by providing the capacitor pattern and the floating pattern below the coil stack, an additional notch is formed in the common mode attenuation characteristic, whereby the laminated common mode filter has the effect of extending the attenuation band.

[0021] Furthermore, the stacked common mode filter achieves broadband characteristics by forming an additional pole (ie, additional capacitance) between the capacitor pattern and the floating pattern and a pole formed by the coil pattern of the electrode stack.

[0022] In addition, the laminated common mode filter has an effect of minimizing variations in the inductance characteristics of the coil pattern by forming a constant distance (pitch) between the channels.

[0023] Furthermore, the stacked common mode filter has the effect of enhancing magnetic coupling (ie, electromagnetic coupling) between the first to third coils and minimizing attenuation of differential signals.

[0024] In addition, the laminated common mode filter can form the electrode stack by stacking thin sheets having two or less via holes, thereby simplifying the manufacturing process.

[0025] Specifically, in the laminated common mode filter, the terminal patterns are arranged at the top and bottom of the electrode stack, the second and third coil patterns of the second channel are located between the first and sixth coil patterns of the first channel, and the fourth and fifth coil patterns of the third channel are located between the third and sixth coil patterns. This minimizes the number of vias required to connect the coil patterns, allowing for two or fewer vias to be formed in each sheet.

[0026] Furthermore, the laminated common mode filter has an 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 existing laminated common mode filter in the same size.

[0027] Furthermore, since the short circuit formed by the floating pattern, the inductor pattern, and the ground pattern is configured by the third stacked body provided below the coil stacked body, the laminated common mode filter can easily adjust and control the second resonant frequency.

[0028] Furthermore, the stacked common mode filter has an effect of being able to adjust the distance between the first resonant frequency and the second resonant frequency by placing or removing a magnetic sheet at the lowermost portion of the filter stack.

[0029] Furthermore, the stacked common mode filter can prevent stress from being concentrated in regions where the via conductors are located during stacking by distributing stress in a non-overlapping manner.

[0030] Furthermore, since the pressure applied to the stacked body is dispersed by the dispersed arrangement of the via conductors during the stacking process, the laminated common mode filter can prevent cracks from being formed in the stacked body during the stacking process.

[0031] Furthermore, since the pressure applied to the stacked body during the stacking process is dispersed by the dispersed arrangement of the via conductors, the laminated common mode filter can prevent the occurrence of a short circuit by avoiding compression of electrodes caused by pressure concentration.

[0032] Furthermore, since the via-hole conductors are dispersedly arranged, the laminated common mode filter can prevent unevenness between the via-hole conductor region and the peripheral region during the stacking process, thereby flattening the surface of the stacked body.

[0033] In addition, the laminated common mode filter does not include a magnetic layer, thereby avoiding loss caused by the magnetic substrate and improving the common mode attenuation characteristics at the first resonance point.

[0034] In addition, the laminated common mode filter does not include a magnetic layer, thereby avoiding loss caused by the magnetic substrate and improving the common mode attenuation characteristics at the first resonance point.

[0035] In addition, compared with existing laminated common mode filters, the laminated common mode filter can meet the cut-off frequency characteristics required by the industrial market by reducing the insertion loss between two channels.

[0036] In addition, compared with the existing laminated common mode filter, since the laminated common mode filter is composed of a low-temperature co-fired ceramic stack without a magnetic layer, the common mode impedance at the main resonance point F can be enhanced.

Brief Description of the Drawings

[0037] Figure 1 It is a perspective view of a multilayer common mode filter according to one embodiment of the present invention.

[0038] Figure 2 Is used to illustrate Figure 1 Exploded perspective view of the filter stack.

[0039] Figure 3 Is used to illustrate Figure 2 Exploded perspective view of the first stack.

[0040] Figure 4 Is used to illustrate Figure 3 Figure 1 of the first slice.

[0041] Figure 5 Is used to illustrate Figure 3 Figure 2 of the second slice.

[0042] Figure 6 Is used to illustrate Figure 3 Figure 3 of the third slice.

[0043] Figure 7 Is used to illustrate Figure 3 Figure 4 of the fourth slice.

[0044] Figure 8 Is used to illustrate Figure 2 Exploded perspective view of the second stack.

[0045] Figure 9 Is used to illustrate Figure 8 Figure 5 of the fifth slice.

[0046] Figure 10 Is used to illustrate Figure 8 Figure 6 of the sixth slice.

[0047] Figure 11 Is used to illustrate Figure 8 Figure 7 of the seventh slice.

[0048] Figure 12 Is used to illustrate Figure 8 Figure 8 of the eighth slice.

[0049] Figure 13 It shows Figure 2 Cross-sectional view of a vertical section of the coil stack.

[0050] Figure 14 Is used to illustrate Figure 2 Exploded perspective view of the third stack.

[0051] Figure 15 Is used to illustrate Figure 14 Figure 9 of the ninth slice.

[0052] Figure 16 Is used to illustrate Figure 14 Figure 10 of the middle slice.

[0053] Figure 17 Is used to illustrate Figure 14 Figure 11 of the middle slice.

[0054] Figure 18 Is used to illustrate Figure 14 Figure 12 of the middle slice.

[0055] Figure 19 FIG. 1 is a diagram showing an equivalent circuit of a multilayer common mode filter according to an embodiment of the present invention.

[0056] Figure 20 This is a graph comparing the common-mode attenuation characteristics of the multilayer common mode filter according to one embodiment of the present invention and a conventional multilayer common mode filter.

[0057] Figure 21This is a graph comparing the insertion loss characteristics of the multilayer common mode filter according to one embodiment of the present invention and a conventional multilayer common mode filter.

[0058] Figure 22 This is a graph comparing the common mode impedance characteristics of the multilayer common mode filter according to one embodiment of the present invention and a conventional multilayer common mode filter. [Specific implementation method]

[0059] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0060] The embodiments are provided to more fully illustrate the present invention to those skilled in the art. The following embodiments may be modified in various other ways, 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 concepts of the present invention.

[0061] The terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. In addition, in this specification, unless the context clearly defines otherwise, a singular expression may include a plural expression.

[0062] In the description of the embodiments, when each layer (film), region, pattern, or structure is described as being formed “on” or “under” each substrate, layer (film), region, pad, or pattern, this includes two expressions, namely, forming a layer “directly” on another layer or “having another layer (indirectly) interposed between two layers.” In addition, the reference of each layer being “on” or “under” is based on the drawings.

[0063] The accompanying drawings are only used to help understand the spirit of the present invention and should not be interpreted as limiting the scope of the present invention. In addition, in the accompanying drawings, relative thickness, length or size may be exaggerated for convenience and clarity of description.

[0064] See also Figure 1 According to one embodiment of the present invention, a stacked common mode filter 100 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. The following description uses the stacked common mode filter 100 operating as a three-channel C-PHY common mode filter as an example.

[0065] The filter stack 110 is a stack of thin sheets, on which are arranged six coil patterns forming three channels, capacitor patterns for adjusting characteristics such as resonant frequency, floating patterns, inductor patterns, and ground patterns. The stacked common mode filter 100 uses the capacitor patterns and floating patterns that form capacitance, the inductor patterns that create inductance, and the ground patterns that provide grounding to adjust resonance point (resonance frequency) shifts and cutoff characteristics.

[0066] See also Figure 2 The filter stack 110 includes a first stack 200 , a second stack 300 disposed below the first stack, and a third stack 500 disposed below the second stack.

[0067] The first stacked body 200 is formed by stacking a plurality of thin sheets on which metal patterns are formed.

[0068] For example, see Figure 3 The first stack 200 includes a first sheet 210, a second sheet 220 disposed below the first sheet, a third sheet 230 disposed below the second sheet, and a fourth sheet 240 disposed below the third sheet. The first sheet 210 to the fourth sheet 240 are all made of ceramic material.

[0069] Here, a first terminal pattern 212 and a second terminal pattern 214 are formed on the first sheet 210 , a first coil pattern 222 is formed on the second sheet 220 , a second coil pattern 232 is formed on the third sheet 230 , and a third coil pattern 242 is formed on the fourth sheet 240 .

[0070] See also Figure 4 A first terminal pattern 212 and a second terminal pattern 214 for connecting the coil patterns 222 , 232 , and 242 of the first stacked body 200 to external electrodes are formed on the first sheet 210 .

[0071] The first terminal pattern 212 is located on the upper surface of the first thin sheet 210. A first end portion 212a of the first terminal pattern 212 is disposed adjacent to the center of the first thin sheet 210.

[0072] The second end portion 212b of the first terminal pattern 212 is disposed aligned with the first side surface of the first sheet 210. Therefore, the second end portion 212b of the first terminal pattern 212 is exposed to the second side surface of the filter stack 110 and connected to the fourth external electrode 150.

[0073] The second terminal pattern 214 is provided on the upper surface of the first sheet 210 in a manner spaced apart from the first terminal pattern 212. The second terminal pattern 214 is provided between the first terminal pattern 212 and the fourth side of the first sheet 210 and is offset toward the fourth side of the first sheet 210.

[0074] The first end portion 214a of the second terminal pattern 214 is disposed adjacent to the center of the first sheet 210. The first end portion 214a of the second terminal pattern 214 is spaced apart from the first end portion 212a of the first terminal pattern 212 by a predetermined distance.

[0075] The second end portion 214b of the second terminal pattern 214 is aligned with the second side surface of the first sheet 210. Therefore, the second end portion 214b of the second terminal pattern 214 is separated from the second end portion 212b of the first terminal pattern 212 by a predetermined distance, is exposed to the second side surface of the filter stack 110, and is connected to the sixth external electrode 170.

[0076] See also Figure 5 The second sheet 220 is disposed below the first sheet 210. The second sheet 220 is provided with a first via hole V1 and a first coil pattern 221 forming a first channel.

[0077] The first coil pattern 222 is disposed on the upper surface of the second sheet 220. The first coil pattern 222 is wound multiple times on the upper surface of the second sheet 220 to form 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 sheet 220 to form the first annular structure. As an example, the first coil pattern 222 forms a first annular structure having a rectangular shape.

[0078] The first end 222a of the first coil pattern 222 is disposed in the inner circumference of the first annular structure and adjacent to the center of the second sheet 220. The first end 222a of the first coil pattern 222 is connected to the first end 212a of the first terminal pattern 212 through a via.

[0079] The second end portion 222b of the first coil pattern 222 is disposed in the outer peripheral region of the first annular structure and aligned with the first side surface of the second sheet 220. Thus, the second end portion 222b of the first coil pattern 222 is exposed to the first side surface of the filter stack 110 and connected to the first external electrode 120.

[0080] The first via hole V1 is disposed adjacent to the center of the second sheet 220 and spaced apart from the first end 222a of the first coil pattern 222. The first via hole V1 is disposed opposite the center of the second sheet 220, and the first end 222a of the first coil pattern 222 is disposed between the first via hole V1 and the center of the second sheet 220.

[0081] The first via hole V1 is formed through the second sheet 220. The upper portion of the first via hole V1 is connected to the second terminal pattern 214, and the lower portion of the first via hole V1 is connected to the second coil pattern 232 and the third coil pattern 242 formed on the third sheet 230. The coil pattern will be described later.

[0082] See also Figure 6 The third sheet 230 is disposed below the second sheet 220. The third sheet 230 is provided with a second coil pattern 232 forming a second channel.

[0083] The second coil pattern 232 is disposed on the upper surface of the third sheet 230. The second coil pattern 232 is wound multiple times around the upper surface of the third sheet 230 to form 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 sheet 230 to form the second annular structure. For example, the second coil pattern 232 forms a rectangular second annular structure.

[0084] The first end 232a of the second coil pattern 232 is disposed in the inner circumference of the second annular structure and adjacent to the center of the third sheet 230. The first end 232a of the second coil pattern 232 is connected to the first end 214a of the second terminal pattern 214 through the first via hole V1 of the second sheet 220.

[0085] The second end portion 232b of the second coil pattern 232 is disposed in an outer peripheral region of the second annular structure and is aligned with the first side surface of the third sheet 230. The second end portion 232b of the second coil pattern 232 is spaced a predetermined distance from the second end portion 222b of the first coil pattern 222, is exposed to the first side surface of the filter stack 110, and is connected to the second external electrode 130.

[0086] See also Figure 7 The fourth sheet 240 is disposed below the third sheet 230. The fourth sheet 240 is provided with a third coil pattern 242 that forms a second channel together with the second coil pattern 232.

[0087] 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 the third annular structure. As an example, the third coil pattern 242 forms the third annular structure having a rectangular shape.

[0088] The first end 242a of the third coil pattern 242 is disposed in the inner circumferential region of the third annular structure, 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, and is connected to the first end 214a of the second terminal pattern 214 through a first via V1 of the second sheet 220.

[0089] The second end 242b of the third coil pattern 242 is disposed at the outer periphery of the third annular structure and aligned with the first side of the fourth sheet 240. The second end 242b of the third coil pattern 242 is spaced a predetermined distance from the second end 222b of the first coil pattern 222.

[0090] The second end portion 242 b of the third coil pattern 242 is aligned with the second end portion 232 b of the second coil pattern 232 and exposed to the first side surface of the filter stack 110 to be connected to the second external electrode 120 together with the second end portion 232 b of the second coil pattern 232 .

[0091] The second stacked body 300 is disposed below the first stacked body 200 and is formed by stacking a plurality of thin sheets having metal patterns formed thereon.

[0092] 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. The fifth sheet 310 to the eighth sheet 340 are all made of ceramic material.

[0093] A fourth coil pattern 312 is formed on the fifth sheet 310. A fifth coil pattern 322 is formed on the sixth sheet 320. A sixth coil pattern 332 is formed on the seventh sheet 330. A third terminal pattern 342 and a fourth terminal pattern 344 are formed on the eighth sheet 340.

[0094] See also 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 .

[0095] The fourth coil pattern 312 is disposed on the upper surface of the fifth sheet 310. The fourth coil pattern 312 is wound multiple times around 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 the fourth annular structure. As an example, the fourth coil pattern 312 forms the fourth annular structure having a rectangular shape.

[0096] The first end 312a of the fourth coil pattern 312 is disposed in the inner circumference of the fourth annular structure, 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, which will be described later.

[0097] The second end 312b of the fourth coil pattern 312 is disposed in the outer peripheral region of the fourth annular structure and aligned with the first side of the fifth sheet 310. The second end 312b of the fourth coil pattern 312 is exposed to the first side surface of the filter stack 110 and connected to the third external electrode 140.

[0098] See also Figure 10 The sixth sheet 320 is disposed below the fifth sheet 310 . The fifth coil pattern 322 , which forms a third channel together with the fourth coil pattern 312 , is disposed on the sixth sheet 320 .

[0099] The fifth coil pattern 322 is disposed 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 the fifth annular structure. As an example, the fifth coil pattern 322 forms the fifth annular structure having a rectangular shape.

[0100] The first end 322a of the fifth coil pattern 322 is disposed at the inner circumference of the fifth annular structure, 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.

[0101] The second end portion 322b of the fifth coil pattern 322 is disposed in an outer peripheral region of the fifth annular structure and aligned with the first side surface of the sixth sheet 320. The second end portion 322b of the fifth coil pattern 322 is disposed to be aligned with the second end portion 312b of the fourth coil pattern 312 and exposed to the first side surface of the filter stack 110 so as to be connected to the third external electrode 140 together with the second end portion 312b of the fourth coil pattern 312.

[0102] See also Figure 11 The seventh sheet 330 is disposed below the sixth sheet 320. The seventh sheet 330 includes a second via hole V2 and a sixth coil pattern 332 forming a first channel together with the first coil pattern 222 of the first stack 200.

[0103] The sixth coil pattern 332 is disposed 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 the sixth annular structure. As an example, the sixth coil pattern 332 forms the sixth annular structure having a rectangular shape.

[0104] The first end 332a of the sixth coil pattern 332 is disposed in the inner circumference of the sixth annular structure, adjacent to the center of the seventh sheet 330. The first end 332a of the sixth coil pattern 332 is connected to a fourth terminal pattern 344 formed on the eighth sheet 340 through a via hole. The fourth terminal pattern 344 will be described later.

[0105] The second end portion 332b of the sixth coil pattern 332 is disposed in an outer peripheral region of the sixth annular structure and is aligned with the first side surface of the seventh sheet 330. The second end portion 332b of the sixth coil pattern 332 is disposed at a predetermined 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, is exposed to the first side surface of the filter stack 110, and is connected to the first external electrode 120.

[0106] The second via hole V2 is disposed adjacent to the center of the seventh sheet 330 and spaced apart from the first end 332a of the sixth coil pattern 332. The second via hole V2 is disposed opposite the center of the seventh sheet 330, and the first end 332a of the sixth coil pattern 332 is disposed between the second via hole V2 and the center of the seventh sheet 330.

[0107] 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 the third terminal pattern 342 formed on the eighth sheet 340, which will be described later.

[0108] See also 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 external electrode are formed on the eighth sheet 340 .

[0109] The third terminal pattern 342 is provided on the upper surface of the eighth sheet 340. The first end 342a of the third terminal pattern 342 is provided 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 a second via V2.

[0110] The second end portion 342b of the third terminal pattern 342 is disposed aligned with the second side surface of the eighth sheet 340. Therefore, the second end portion 342b of the third terminal pattern 342 is exposed to the second side surface of the filter stack 110 and connected to the fifth external electrode 160.

[0111] The fourth terminal pattern 344 is located on the upper surface of the eighth thin sheet 340 and is 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 positioned adjacent to the center of the eighth thin sheet 340. The first end 344a of the fourth terminal pattern 344 is spaced a predetermined distance from the first end 342a of the third terminal pattern 342.

[0112] The second end portion 344b of the fourth terminal pattern 344 is arranged to be aligned with the second side surface of the eighth thin sheet 344. Therefore, the second end portion 344b of the fourth terminal pattern 344 is spaced apart from the second end portion 342b of the third terminal pattern 342 by a predetermined distance and is exposed to the second side surface of the filter stack 110 to be connected to the fourth external electrode 150 together with the second end portion 212b of the first terminal pattern 212.

[0113] The first stack 200 and the second stack 300 form a coil stack 400 , and the coil stack 400 includes coils forming three channels.

[0114] 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.

[0115] Here, the first coil pattern 222 and the sixth coil pattern 332 form a first coil, which is a series inductor that constitutes the first channel. The second coil pattern 232 and the third coil pattern 242 form a second coil, which is a series inductor that constitutes the second channel. The fourth coil pattern 312 and the fifth coil pattern 322 form a third coil, which is a series inductor that constitutes the third channel.

[0116] Thus, the coil stack 400 forms a stack in which the coil pattern of the first channel, the coil pattern of the second channel, the coil pattern of the second channel, the coil pattern of the third channel, the coil pattern of the third channel, and the coil pattern of the first channel are sequentially arranged (stacked).

[0117] Therefore, in the laminated common mode filter 100 according to an embodiment of the present invention, the distance (pitch) between the coil patterns forming each channel can be kept constant, thereby keeping the resistance and inductance of the coil patterns forming each channel uniform.

[0118] Furthermore, the laminated common mode filter 100 according to one embodiment of the present invention can minimize variations in the inductance characteristics of the coil patterns and the common-mode attenuation characteristics by placing terminal patterns for connection to external electrodes at the top and bottom of the coil stack 400. If the terminal patterns are only located at the top or bottom, the inductance characteristics of each channel or each coil pattern may vary, leading to variations in the common-mode attenuation characteristics.

[0119] In the laminated common mode filter 100 according to one embodiment of the present invention, the terminal patterns are arranged 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 arranged between the first coil pattern 222 and the sixth coil pattern 332 of the first channel, and the fourth coil pattern 312 and the fifth coil pattern 322 of the third channel are arranged between the third coil pattern 242 and the sixth coil pattern 332. Thus, the number of vias required to connect the coil patterns can be minimized. The laminated common mode filter 100 according to one embodiment of the present invention forms two or fewer vias in each sheet.

[0120] See also Figure 13 The first coil pattern 222 and the sixth coil pattern 332 are disposed in the coil stack 400 and are respectively disposed adjacent to the upper and lower portions of the coil stack 400, thereby forming a first channel. The second coil pattern 232 and the third coil pattern 232 are disposed in the coil stack 400 and are disposed (stacked) parallel to each other between the first coil pattern 222 and the sixth coil pattern 332, thereby forming a second channel. The fourth coil pattern 312 and the fifth coil pattern 322 are disposed in the coil stack 400 and are disposed (stacked) parallel to each other between the third coil and the sixth coil, thereby forming a third channel.

[0121] Therefore, the stacked common mode filter 100 according to an embodiment of the present invention can be configured such that the distances (intervals) between the first channel and the second channel, between the second channel and the third channel, and between the third channel and the first channel remain constant.

[0122] Furthermore, the laminated common mode filter 100 according to an embodiment of the present invention can minimize variations in the inductance characteristics of the coil pattern by maintaining a constant distance (interval) between channels.

[0123] In addition, in the laminated common mode filter 100 according to one embodiment of the present invention, since the terminal patterns connecting the coil pattern to the external electrode are arranged at the top and bottom of the filter stack 110, the distance between the coil pattern and the terminal pattern can be made the same for all channels, thereby ensuring that the resistance and inductance of the coil pattern forming each channel are consistent.

[0124] In addition, the laminated common mode filter 100 according to an embodiment of the present invention can enhance the magnetic coupling (ie, electromagnetic coupling) between the first coil to the third coil and minimize the attenuation of the differential signal.

[0125] The coil stack 110 is configured such that a plurality of via conductors formed by via holes for connecting the coil pattern and the terminal pattern are distributed without overlapping each other.

[0126] For example, the first via conductor 710 is formed by a via hole connecting the first terminal pattern 212 and the first coil pattern 222 .

[0127] The second via conductor 720 is formed through a via hole connecting the fourth terminal pattern 344 and the sixth coil pattern 332 , and is spaced apart from and does not overlap with the first via conductor 710 in a top view of the coil stack 400 .

[0128] The third via conductor 730 is formed by a via connecting the second terminal pattern 214, the second coil pattern 232 and the third coil pattern 242, and is separated from the first via conductor 710 and the second via conductor 720 in the top view of the coil stack body 400, and does not overlap with the first via conductor 710 and the second via conductor 720.

[0129] The fourth via conductor 740 is formed by a via connecting the third terminal pattern 342, the fourth coil pattern 312 and the fifth coil pattern 322, and is separated from the first via conductor 710 to the third via conductor 730 in the top view of the coil stack body 400, and does not overlap with the first via conductor 710 to the third via conductor 730.

[0130] In other words, the first virtual line L1 is defined as a straight line that penetrates the upper and lower surfaces of the coil stack 400 and passes through the center of the first via conductor 710 in a vertical cross-sectional view of the coil stack 400 .

[0131] The second imaginary line L2 is defined as a straight line that passes through the upper and lower surfaces of the coil stack 400 and the center of the second via conductor 720 in a vertical cross-sectional view of the coil stack 400. The second imaginary line L2 is spaced a predetermined distance from the first imaginary line L1 and is parallel to the first imaginary line L1.

[0132] The third virtual line L3 is defined as a straight line that passes through the upper and lower surfaces of the coil stack 400 and through the center of the third via conductor 730 in a vertical cross-sectional view of the coil stack 400. The third virtual line L3 is positioned opposite the first virtual line L1, and the second virtual line L2 is positioned between the third virtual line L3 and the first virtual line L1. The third virtual line L3 is separated from the first virtual line L1 and the second virtual line L2 by a predetermined distance and is parallel to the first virtual line L1 and the second virtual line L2.

[0133] The fourth virtual line L4 is defined as a straight line that passes through the upper and lower surfaces of the coil stack 400 and through the center of the fourth via conductor 740. The fourth virtual line L4 is disposed opposite the second virtual line L2, the first virtual line L1 is disposed between the fourth virtual line L4 and the second virtual line L2, the fourth virtual line L4 is separated from the second virtual line L2 and the third virtual line L3 by a predetermined distance, and is parallel to the first virtual line L1 to the third virtual line L3.

[0134] Thus, the laminated common mode filter 100 according to an embodiment of the present invention can disperse pressure by distributing the via conductors in a non-overlapping manner, thereby preventing pressure from being concentrated in the region where the via conductors are located during the stacking process.

[0135] Furthermore, since the pressure applied to the stacked body is dispersed by the dispersed arrangement of the via conductors during the stacking process, the laminated common mode filter 100 according to an embodiment of the present invention can prevent cracks from being formed in the stacked body during the stacking process.

[0136] Furthermore, since the pressure applied to the stacked body during stacking is dispersed by the dispersed arrangement of the via conductors, the laminated common mode filter 100 according to an embodiment of the present invention can prevent the occurrence of short circuits by avoiding compression of electrodes caused by pressure concentration.

[0137] Furthermore, since the via-hole conductors are dispersedly arranged, the laminated common mode filter 100 according to an embodiment of the present invention can flatten the surface of the stacked body by preventing unevenness between the via-hole conductor region and the surrounding region during the stacking process.

[0138] The third stacked body 500 is disposed below the second stacked body 300. The third stacked body 500 is formed by stacking a plurality of thin sheets formed with metal patterns. 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, and a twelfth sheet 540 located below the eleventh sheet 530. The ninth to twelfth sheets 410 to 440 are all made of ceramic material.

[0139] Metal patterns 511-516 and 522 for forming capacitors are formed on the ninth sheet 510 and the tenth sheet 520. A metal pattern 532 for forming an inductor is formed on the eleventh sheet 530. A metal pattern 542 for forming a ground is formed on the twelfth sheet 540.

[0140] The ninth sheet 510 is disposed below the eighth sheet 340 and has a plurality of capacitor patterns arranged on an upper surface of the ninth sheet 510. The capacitor patterns may be provided as a plurality of patterns disposed at the input and output ends of the laminated common mode filter 100.

[0141] For example, see Figure 15 The capacitor pattern includes 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 .

[0142] The first capacitor pattern 511 is disposed on the upper surface of the ninth sheet 510 .

[0143] The first end portion 511 a of the first capacitor pattern 511 is adjacent to the center of the ninth sheet 510 .

[0144] The second end portion 511b of the first capacitor pattern 511 is disposed to be aligned with the first side surface of the ninth sheet 510. The first capacitor pattern 511 is exposed to the first side surface of the filter stack 110 and is connected to the first external electrode 120.

[0145] The second capacitor pattern 512 is disposed on the upper surface of the ninth thin sheet 510 and is spaced apart from the first capacitor pattern 511. The second capacitor pattern 512 is spaced apart from the first capacitor pattern 511 and is offset toward the fourth side of the ninth thin sheet 510.

[0146] The first end portion 512a of the second capacitor pattern 512 is adjacent to the center of the ninth thin sheet 510. The second end portion 512b of the second capacitor pattern 512 is aligned with the first side surface of the ninth thin sheet 510. The second capacitor pattern 512 is exposed to the first side surface of the filter stack 110 and is connected to the second external electrode 130.

[0147] The 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 offset toward the third side of the ninth sheet 510. The third capacitor pattern 513 is disposed opposite the second capacitor pattern 512, with the first capacitor pattern 511 disposed between the third capacitor pattern 513 and the second capacitor pattern 512.

[0148] A first end portion 513a of the third capacitor pattern 513 is adjacent to the center of the ninth thin sheet 510. A second end portion 513b of the third capacitor pattern 513 is disposed so as to be aligned with a first side surface of the ninth thin sheet 510. The third capacitor pattern 513 is exposed to a first side surface of the filter stack 110 and is connected to the third external electrode 140.

[0149] The fourth capacitor pattern 514 is disposed on the upper surface of the ninth sheet 510 .

[0150] The first end portion 514a of the fourth capacitor pattern 514 is adjacent to the center of the ninth thin 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.

[0151] The second end portion 514b of the fourth capacitor pattern 514 is disposed to be aligned with the second side surface of the ninth sheet 510. The fourth capacitor pattern 514 is exposed to the second side surface of the filter stack 110 and is connected to the fourth external electrode 150.

[0152] The fifth capacitor pattern 515 is disposed on the upper surface of the ninth thin sheet 510. The fifth capacitor pattern 515 is spaced apart from the fourth capacitor pattern 514 and is offset toward the third side of the ninth thin sheet 510.

[0153] The first end portion 515a of the fifth capacitor pattern 515 is adjacent to the center of the ninth thin sheet 510. The first end portion 515a of the fifth capacitor pattern 515 faces the first end portion 513a of the third capacitor pattern 513.

[0154] The second end portion 515b of the fifth capacitor pattern 515 is disposed to be aligned with the second side surface of the ninth sheet 510. The fifth capacitor pattern 515 is exposed to the second side surface of the filter stack 110 and is connected to the fifth external electrode 160.

[0155] The sixth capacitor pattern 516 is disposed on the upper surface of the ninth thin sheet 510. The sixth capacitor pattern 516 is spaced apart from the fourth capacitor pattern 514 and the fifth capacitor pattern 515 and is offset toward the fourth side of the ninth thin sheet 510. The sixth capacitor pattern 516 is disposed opposite the fifth capacitor pattern 515, with the fourth capacitor pattern 514 interposed between the sixth capacitor pattern 516 and the fifth capacitor pattern 515.

[0156] The first end portion 516a of the sixth capacitor pattern 516 is adjacent to the center of the ninth thin sheet 510. The first end portion 516a of the sixth capacitor pattern 516 faces the first end portion 512a of the second capacitor pattern 512.

[0157] The second end portion 516 b of the sixth capacitor pattern 516 is positioned to be aligned with the second side surface of the ninth sheet 510 . The sixth capacitor pattern 516 is exposed to the second side surface of the filter stack 110 and is connected to the sixth external electrode 170 .

[0158] It is assumed that the first to third external electrodes 120 to 140 arranged on the first side surface of the filter stack 110 are used as the input end of the laminated common mode filter 100, and the third to sixth external electrodes 140 to 170 arranged on the second side surface of the filter stack 110 are used as the output end of the laminated common mode filter 100.

[0159] The first to third capacitor patterns 511 to 513 are disposed on a first side surface of the filter stack 110 and are 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 a second side surface of the filter stack 110 and are connected to the fourth to fifth external electrodes 150 to 160 in a one-to-one correspondence.

[0160] The filter stack 110 may include a ninth sheet 510 having 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 having fourth to sixth capacitor patterns 514 to 516 connected to an output terminal.

[0161] The tenth sheet 520 is disposed below the ninth sheet 510. A floating pattern 522 for forming capacitance is disposed on an upper surface of the tenth sheet 520 together with the capacitor pattern of the ninth sheet 510.

[0162] See also Figure 16 Floating pattern 522 is formed in a plate shape and is provided on the upper surface of tenth sheet 520. The area of floating pattern 522 is smaller than that of tenth sheet 520, and the outer periphery of floating pattern 522 is spaced apart from the four side surfaces of tenth sheet 520. The area of floating pattern 522 is larger than that of inductor pattern 532, which will be described later, and is formed to be no more than 90% of the area of tenth sheet 520.

[0163] The floating pattern 522 overlaps the capacitor pattern of the ninth sheet 510 to form an overlapping region, and capacitance is formed in the overlapping region.

[0164] The floating pattern 522 forms a first overlapping region 522a with the first capacitor pattern 511, forming a first capacitor in the first overlapping region 522a. The floating pattern 522 forms a second overlapping region 522b with the second capacitor pattern 512, forming a second capacitor in the first overlapping region 522a. The floating pattern 522 forms a third overlapping region 522c with the third capacitor pattern 513, forming a third capacitor in the third overlapping region 522c. The floating pattern 522 forms a fourth overlapping region 522d with the fourth capacitor pattern 514, forming a fourth capacitor in the fourth overlapping region 522d. The floating pattern 522 forms a fifth overlapping region 522e with the fifth capacitor pattern 515, forming a fifth capacitor in the fifth overlapping region 522e. The floating pattern 522 forms a sixth overlapping region 522f with the sixth capacitor pattern 516, forming a sixth capacitor in the sixth overlapping region 522f.

[0165] Thus, the floating pattern 522 and the capacitor pattern form a capacitor. Therefore, the laminated common mode filter 100 can extend the attenuation band by forming an additional notch in the common mode attenuation characteristics. In other words, the laminated common mode filter 100 can achieve broadband characteristics by forming an additional pole due to the floating pattern 522 and the capacitor pattern, together with the pole formed by the coil pattern of the filter stack 110.

[0166] The eleventh thin sheet 530 is disposed below the tenth thin sheet 520 , and the inductor pattern 532 is located on an upper surface of the eleventh thin sheet 530 .

[0167] For example, see Figure 17 The inductor pattern 532 is wound on the upper surface of the eleventh sheet 530 to form a seventh loop structure. The inductor pattern 532 is wound around a virtual winding axis passing through the center of the eleventh sheet 530 to form the seventh loop structure. The inductor pattern 532 constitutes a parallel common mode inductor having a predetermined inductance value.

[0168] The first end portion 532 a of the inductor pattern 532 is disposed at an inner circumferential region of the seventh ring structure and is located at the center of the eleventh sheet 530 .

[0169] The second end portion 532 b of the inductor pattern 532 is disposed at an outer peripheral region of the seventh ring structure, and the second end portion 532 b of the inductor pattern 532 is connected to the floating pattern 522 of the tenth sheet 520 through a via hole.

[0170] The length (area) of inductor pattern 532 can vary depending on the desired secondary resonant frequency. As the length of inductor pattern 532 increases, the inductance increases, and the secondary resonant frequency shifts toward lower frequencies. As the length of inductor pattern 532 decreases, the inductance decreases, and the secondary resonant frequency shifts toward higher frequencies. Therefore, the length of inductor pattern 532 is determined based on the desired secondary resonant frequency.

[0171] The inductor pattern 532 may be formed into a multilayer structure of two or more layers. However, when the inductor pattern 532 is a multilayer structure, the height of the laminated common mode filter increases and unnecessary parasitic capacitance is generated between the inductor pattern 532 and the ground pattern 542, as will be described later.

[0172] Therefore, it is preferred that the inductor pattern 532 has a single-layer structure, which can minimize the increase in the filter height and reduce the parasitic capacitance generated between the inductor pattern 532 and the ground pattern 542 .

[0173] The twelfth sheet 540 is disposed below the eleventh sheet 530 , and the ground pattern 542 is formed on the twelfth sheet 540 .

[0174] The ground pattern 542 is connected to the inductor pattern 532 and reduces the influence of floating capacitance formed between the laminated common mode filter 100 and the printed circuit board.

[0175] For example, see Figure 18 , the ground pattern 542 is provided on the upper surface of the twelfth sheet 540. The ground pattern 542 may include a first ground pattern 542a, a second ground pattern 542b, and a third ground pattern 542c.

[0176] The first ground pattern 542a is formed in a plate shape and is located at the center of the upper surface of the twelfth sheet 540. The first ground pattern 542a has an area smaller than the twelfth sheet 540 and is disposed so that its periphery is spaced apart from the four sides of the twelfth sheet 540.

[0177] In the figure, the first ground pattern 542a is formed into a rectangle with a greater horizontal length than a vertical length. The first ground pattern 542a overlaps a portion of the inductor pattern 532, and the inductor pattern 532 has an area that does not overlap with the first ground pattern 542a. In this case, the first ground pattern 542a overlaps a portion of the inductor pattern 532, thereby minimizing parasitic capacitance generated between the ground pattern 542 and the inductor pattern 532.

[0178] The first ground pattern 542 a is connected to the first end portion 532 a of the inductor pattern 532 through a via hole passing through the eleventh sheet 530 .

[0179] The second ground pattern 542b extends from the third side of the first ground pattern 542a and is aligned with the third side of the twelfth sheet 540. A first end of the second ground pattern 542b is connected to the third side of the first ground pattern 542a. A second end of the second ground pattern 542b is aligned with the third side of the twelfth sheet 540 and connected to the seventh external electrode 180.

[0180] The third ground pattern 542c extends from the fourth side of the first ground pattern 542a and is aligned with the fourth side of the twelfth sheet 540. A first end of the third ground pattern 542c is connected to the fourth side of the first ground pattern 542a. A second end of the third ground pattern 542c is aligned with the fourth side of the twelfth sheet 540 and connected to the eighth external electrode 190.

[0181] Thus, the ground pattern 542 is exposed to the third and fourth side surfaces of the filter stack 110 , thereby forming a ground connected to the seventh and eighth external electrodes 180 and 190 .

[0182] The first external electrode 120 is positioned on a first side surface of the filter stack 110. Opposite ends of the first external electrode 120 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0183] The first external electrode 120 is connected to the first coil pattern 222, the sixth coil pattern 322, and the first capacitor pattern 511 exposed on the first side surface of the filter stack 110. The first external electrode 120 is connected to the second end 222b of the first coil pattern 222, the second end 322b of the sixth coil pattern 322, and the second end 511b of the first capacitor pattern 511.

[0184] The second external electrode 130 is located on the first side surface of the filter stack 110. The second external electrode 130 is disposed toward the fourth side surface of the filter stack 110 and is spaced apart from the first external electrode 120. Opposite ends of the second external electrode 130 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0185] The second external electrode 130 is connected to the second coil pattern 232, the third coil pattern 242, and the second capacitor pattern 512 exposed to the first side surface of the filter stack 110. The second external electrode 130 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 512b of the second capacitor pattern 512.

[0186] The third external electrode 140 is located on a first side surface of the filter stack 110. The third external electrode 140 is disposed toward the third side surface of the filter stack 110 and is spaced apart from the first external electrode 120. The third external electrode 140 is opposite the second external electrode 130, with the first external electrode 120 interposed therebetween. Opposite ends of the third external electrode 140 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0187] The third external electrode 140 is connected to the fourth coil pattern 312, the fifth coil pattern 322, and the third capacitor pattern 513 exposed to the first side surface of the filter stack 110. The third external electrode 140 is connected to the second end 312b of the fourth coil pattern 312, the second end 322b of the fifth coil pattern 322, and the second end 513b of the third capacitor pattern 513.

[0188] 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 disposed facing the first external electrode 120. Furthermore, opposite ends of the fourth external electrode 150 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0189] The fourth external electrode 150 is connected to the first terminal pattern 212, the fourth terminal pattern 344, and the fourth capacitor pattern 514 exposed on the second side surface of the filter stack 110. The fourth external electrode 150 is connected to the second end portion 212b of the first terminal pattern 212, the second end portion 344b of the fourth terminal pattern 344, and the second end portion 514b of the fourth capacitor pattern 514.

[0190] The fifth external electrode 160 is located on the second side surface of the filter stack 110. The fifth external electrode 160 is opposite 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 spaced apart from the fourth external electrode 150. Opposite ends of the fifth external electrode 160 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0191] The fifth external electrode 160 is connected to the third terminal pattern 342 and the fifth capacitor pattern 515 exposed to the second side surface of the filter stack 110. The fifth external electrode 160 is connected to the second end 342b of the third terminal pattern 342 and the second end 515b of the fifth capacitor pattern 515.

[0192] The sixth external electrode 170 is located on the second side surface of the filter stack 110. The sixth external electrode 170 is opposite the second external electrode 130, with the filter stack 110 interposed therebetween, and is positioned facing the second external electrode 130. The sixth external electrode 170 is positioned toward 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 the fifth external electrode 160, with the fourth external electrode 150 interposed therebetween. Opposite ends of the sixth external electrode 170 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0193] The sixth external electrode 170 is connected to the second terminal pattern 214 and the sixth capacitor pattern 516 exposed on the second side surface of the filter stack 110. The sixth external electrode 170 is connected to the second end 214b of the second terminal pattern 214 and the second end 516b of the sixth capacitor pattern 516.

[0194] The seventh external electrode 180 is provided on the third side surface of the filter stack 110. The seventh external electrode 180 is connected to the ground pattern 555 exposed to the third side surface of the filter stack 110, and the seventh external electrode 180 is connected to the second end of the second ground pattern 555b exposed to the third side surface of the filter stack 110. The opposite ends of the seventh external electrode 180 may be formed to extend to the upper and lower surfaces of the filter stack 110.

[0195] 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 seventh external electrode 180, and the filter stack 110 is interposed between the seventh external electrode 180 and the eighth external electrode 190. The eighth external electrode 190 is connected to the ground pattern 555 exposed to the third side surface of the filter stack 110. The eighth external electrode 190 is connected to the second end of the third ground pattern 555c exposed to the fourth side surface of the filter stack 110. The 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.

[0196] The first external electrode 120 and the fourth external electrode 150 serve as the input and output terminals of the first channel formed by the first coil pattern 222 and the sixth coil pattern 332. The second external electrode 130 and the sixth external electrode 170 serve as the input and output terminals of the second channel formed by the second coil pattern 232 and the third coil pattern 242. The third external electrode 130 and the fifth external electrode 160 serve as the input and output terminals of the third channel formed by the fourth coil pattern 312 and the fifth coil pattern 322. The seventh external electrode 180 and the seventh external electrode 180 are connected to the ground pattern 555, thereby functioning as ground terminals.

[0197] Figure 19 FIG. 1 shows an equivalent circuit of a multilayer common mode filter 100 according to an embodiment of the present invention. Capacitances 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.

[0198] The filter stack 110 is formed by stacking the first and second stacks 20 and 300 formed with coil patterns to form a coil stack 400 , and placing the third stack 500 including a capacitor pattern, a floating pattern 522 , and inductor patterns 532 and 542 below the coil stack 400 .

[0199] Thus, the capacitor patterns connected between the coils of the respective channels and the external electrodes are connected to each other, and a coupling effect is generated between the capacitor patterns and the floating pattern 522. Thus, due to the capacitor patterns and the floating pattern 522, additional capacitances C1 to C6 are formed between the coils of the respective channels and the external electrodes.

[0200] Therefore, the laminated common mode filter 100 according to one embodiment of the present invention can increase capacitance without adding an electrode layer including a coil pattern or increasing the area of the coil pattern, thereby achieving greater capacitance while maintaining the same size as the conventional laminated common mode filter 10.

[0201] Furthermore, in the laminated common mode filter 100 according to an embodiment of the present invention, since the capacitor pattern and the floating pattern 522 form additional capacitance, an additional notch may be formed in the common mode attenuation characteristic, thereby expanding the attenuation band.

[0202] Opposite ends of the inductor pattern 532 are connected to the floating pattern 522 and the ground pattern 555 , respectively, forming a short circuit between the floating pattern 522 and the ground pattern 555 .

[0203] The inductance of the inductor pattern 532 may be defined by the length of the inductor pattern 532. The inductance of the inductor pattern 532 is a dominant factor in adjusting and controlling the secondary resonant frequency of the stacked common mode filter 100.

[0204] The primary resonant frequency is formed by the capacitance generated between the first coil, the second coil, and the third coil, while the secondary resonant frequency is formed by the capacitor patterns 511 to 516 , the floating pattern 522 , and the inductor pattern 532 .

[0205] In this case, the inductor pattern 532 has a relatively high value compared to the capacitance formed between the capacitor patterns 511 to 516 and the floating pattern 522 , and thus the inductor pattern 532 becomes a dominant factor in determining the secondary resonance frequency.

[0206] Inductor pattern 532 has a numerical adjustment range that allows the secondary resonant frequency to be adjusted to various values within the same area. Furthermore, due to its smaller area compared to capacitor patterns 511 to 516, it can improve design flexibility. Compared to inductor pattern 532, capacitor patterns 511 to 516 form relatively smaller capacitance with floating pattern 522, thereby reducing losses during signal transmission.

[0207] Thus, the inductor pattern 532 serves as a dominant factor in determining the secondary resonant frequency and can reduce the influence of parasitic inductance (parasitic L) that varies according to the chip mounting direction, thereby preventing characteristic deviation due to the mounting direction.

[0208] Unlike conventional multilayer common mode filters composed of a stack including magnetic layers (ferrite layers), a multilayer common mode filter according to an embodiment of the present invention is composed of a low-temperature co-fired ceramic (LTCC) stack without a magnetic layer.

[0209] Figure 20 Curve A in FIG. 1 shows the test results of the common-mode attenuation characteristics of the conventional laminated common-mode filter, and curve B shows the test results of the common-mode attenuation characteristics of the laminated common-mode filter according to an embodiment of the present invention.

[0210] The existing laminated common mode filter forms a main resonance point at approximately 2.70 GHz, and the common mode attenuation characteristic of the main resonance point is approximately -29.87 dB.

[0211] The common mode filter according to one embodiment of the present invention forms a main resonance point at approximately 2.37 GHz, and the common mode attenuation characteristic of the main resonance point is approximately -47.06 dB.

[0212] It can be seen that since the laminated common mode filter according to an embodiment of the present invention does not contain a magnetic layer, the loss caused by the magnetic material can be avoided, thereby enhancing the common mode attenuation characteristics of the main resonance point.

[0213] Generally, a multilayer common mode filter needs to have a cutoff frequency characteristic of approximately -3dB.

[0214] See also Figure 21In the existing laminated common-mode filter, the insertion loss C1 between the first channel line and the second channel line is measured to be greater than or equal to -3dB in the entire frequency band, the insertion loss C2 between the first channel line and the third channel line is measured to be less than -3dB in the frequency band of approximately 5.4GHz to 7.2GHz, and the insertion loss C3 between the second channel line and the third channel line is measured to be less than -3dB in the frequency band of approximately 6.5GHz.

[0215] Therefore, in existing laminated common-mode filters, although the insertion loss C1 between the first and second channel lines meets the -3dB standard required by the industrial market across the entire frequency band, the insertion loss C2 between the first and third channel lines and the insertion loss C3 between the second and third channel lines are measured to be equal to or less than -3dB in some frequency bands, thereby failing to meet the cutoff frequency characteristics required by the industrial market.

[0216] On the other hand, in the laminated common-mode filter according to one embodiment of the present invention, the insertion loss D1 between the first and second channel lines, the insertion loss D2 between the first and third channel lines, and the insertion loss D3 between the second and third channel lines are smaller than those in existing laminated common-mode filters, and are greater than or equal to -3dB across the entire frequency band. This shows that it meets the cutoff frequency characteristics required by the industrial market.

[0217] See also Figure 22 , the common-mode impedance Z1 of the multilayer common-mode filter according to an embodiment of the present invention is lower than the common-mode impedance Z2 of the conventional multilayer common-mode filter at a frequency of about 100 MHz.

[0218] However, at the main resonance point F, the common mode impedance Z2 of the conventional laminated common mode filter is measured to be approximately 500 ohms, while the common mode impedance Z1 of the laminated common mode filter according to an embodiment of the present invention is measured to be approximately 5000 ohms.

[0219] As described above, compared with the existing multilayer common mode filter, since the multilayer common mode filter according to one embodiment of the present invention is composed of a low-temperature co-fired ceramic stack without a magnetic layer, its Q factor is significantly improved, and accordingly the common mode impedance at the main resonance point F is also greatly improved.

[0220] The above description is merely an explanation of the technical idea of the present invention, and those skilled in the art may change and deform the present invention in various ways without departing from the essential features 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 rather as illustrating the technical idea of the present invention. The technical idea of the present invention is not limited by the embodiments. The scope of protection 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 included within the scope of rights of the present invention.

Claims

1. A laminated common mode filter, characterized in that: include: a first stacked body having a plurality of coil patterns; a second stacked body having a plurality of coil patterns and disposed below the first stacked body; as well as A third stacking body is arranged below the second stacking body, The third stack comprises: a plurality of capacitor patterns disposed below the second stack; a floating pattern disposed below the plurality of capacitor patterns and forming additional capacitance by overlapping the plurality of capacitor patterns; a ground pattern disposed below the floating pattern; and an inductor pattern provided between the floating pattern and the ground pattern, A first end portion of the inductor pattern is connected to the floating pattern, and a second end portion of the inductor pattern is connected to the ground pattern.

2. The laminated common mode filter according to claim 1, wherein The first stack, the second stack, and the third stack each include a low-temperature co-fired ceramic stack.

3. The laminated common mode filter according to claim 1, wherein The first stack includes a first coil pattern, a second coil pattern, and a third coil pattern, the second stacked body includes a fourth coil pattern, a fifth coil pattern, and a sixth coil pattern, The first stack and the second stack constitute a coil stack. The coil stack is configured 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 located between the first coil pattern and the sixth coil pattern to form a second coil, and the second coil forms a second channel. The fourth coil pattern and the fifth coil pattern are interposed between the third coil pattern and the sixth coil pattern and form a third coil, and the third coil forms a third channel.

4. The laminated common mode filter according to claim 1, wherein The first stack comprises: First slice; a first terminal pattern located on a first surface of the first sheet; a second terminal pattern located on the first surface of the first sheet and spaced apart from the first terminal pattern; a second sheet disposed below the first sheet; a first coil pattern wound on the first surface of the second sheet to form a rectangular first ring structure, comprising a first end located in an inner peripheral region of the first ring structure and connected to the first terminal pattern via a via hole passing through the first sheet, and a second end located in an outer peripheral region of the first ring structure; a third sheet located below the second sheet; a second coil pattern wound on the first surface of the third sheet to form a rectangular second annular structure, comprising a first end located in an inner peripheral region of the second annular structure and connected to the second terminal pattern via a via hole passing through the first sheet and the second sheet, and a second end located in an outer peripheral region of the second annular structure; a fourth sheet located below the third sheet; and A third coil pattern is wound on the first surface of the fourth sheet to form a rectangular third annular structure, including a first end located in an inner peripheral area of the third annular structure and connected to a second end of the second coil pattern through a via hole passing through the third sheet, and a second end located in an outer peripheral area of the third annular structure.

5. The laminated common mode filter according to claim 1, wherein The second stack comprises: the fifth sheet; a fourth coil pattern wound on the first surface of the fifth sheet to form a fourth rectangular annular structure, comprising a first end located in an inner peripheral region of the fourth annular structure and a second end located in an outer peripheral region of the fourth annular structure; a sixth sheet disposed below the fifth sheet; a fifth coil pattern wound on the first surface of the sixth sheet to form a rectangular fifth annular structure, comprising a first end located in an inner peripheral region of the fifth annular structure and connected to the first end of the fourth coil pattern via a via hole passing through the fifth sheet, and a second end located in an outer peripheral region of the fifth annular structure; a seventh sheet disposed below the sixth sheet; a sixth coil pattern wound on the first surface of the seventh sheet to form a sixth annular structure, comprising a first end located in an inner peripheral region of the sixth annular structure and a second end located in an 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, including a first end portion connected to the first end portion of the fourth coil pattern and the first end portion of the fifth coil pattern through a via hole passing through the fifth sheet, the sixth sheet, and the seventh sheet; and A fourth terminal pattern, which is located on the first surface of the seventh sheet and is spaced apart from the third terminal pattern, includes a first end portion connected to the first end portion of the sixth coil pattern through a via hole passing through the seventh sheet.

6. The laminated common mode filter according to claim 1, wherein The third stack comprises: The ninth slice; 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; a floating pattern located on the first surface of the tenth sheet, overlapping with the plurality of capacitor patterns to form a plurality of overlapping regions, and configured to form additional capacitance in the plurality of overlapping regions; an eleventh sheet, located below the tenth sheet; an inductor pattern wound on the first surface of the tenth sheet to form a seventh annular structure, including a first end portion located in an inner peripheral area of the seventh annular structure and connected to the floating pattern; a twelfth sheet located below the eleventh sheet; and A ground pattern is located on the first surface of the twelfth sheet and is connected to the second end of the inductor pattern.

7. The laminated common mode filter according to claim 6, wherein: The inductor pattern includes: a first area overlapping the ground pattern; and A second region does not overlap with the ground pattern.

8. The laminated common mode filter according to claim 1, wherein A filter stack formed by stacking the first stack, the second stack, and the third stack has a first resonant frequency and a second resonant frequency higher than the first resonant frequency. As the length of the inductor pattern increases, the second resonant frequency shifts toward a higher frequency.

9. The laminated common mode filter according to claim 1, wherein: A filter stack formed by stacking the first stack, the second stack, and the third stack has a first resonant frequency and a second resonant frequency higher than the first resonant frequency. As the length of the inductor pattern decreases, the second resonant frequency shifts toward a lower frequency.

10. The laminated common mode filter according to claim 1, wherein The filter stack formed by stacking the first stack, the second stack, and the third stack 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 laminated common mode filter further comprises: a first external electrode disposed on the first side surface and connected to the second end of the first coil pattern, the second end of the sixth coil pattern, and the third end of the first capacitor pattern exposed to the first side surface; a second external electrode disposed on the first side surface and connected to a second end portion of the second coil pattern, a second end portion of the third coil pattern, and a second end portion of the second capacitor pattern exposed to the first side surface; a third external electrode disposed on the first side surface and connected to the second end of the fourth coil pattern, the second end of the fifth coil pattern, and the second end of the third capacitor pattern exposed to the first side surface; a fourth external electrode disposed on the second side surface and connected to the second end of the first terminal pattern, the second end of the fourth terminal pattern, and the second end of the fourth capacitor pattern exposed to the second side surface; a fifth external electrode disposed on the second side surface and connected to a second end portion of the third terminal pattern and a second end portion of the fifth capacitor pattern exposed to the second side surface; and A sixth external electrode is disposed on the second side surface and connected to a second end portion of the second terminal pattern exposed to the second side surface and a second end portion of the sixth capacitor pattern.

11. The laminated common mode filter according to claim 10, wherein: Also includes: a seventh external electrode disposed on the third side surface and connected to the first end portion of the ground pattern exposed to the third side surface; as well as an eighth external electrode disposed on the fourth side surface and connected to the second end portion of the ground pattern exposed to the fourth side surface.

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