# US 10,374,568 B2 · Common mode filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,568 B2 - Document ID: US10374568B2 - Status: Granted - Kind: B2 - Application number: 16/192,047 - Filed: 2018-11-15 - Published: 2019-03-21 - Granted: 2019-08-06 - Earliest claimed: 2016-03-30 - Assignees: TDK Corporation - Applicants: TDK Corporation - Inventors: Tsutomu Kobayashi; Toshio Tomonari; Emi Ito; Yuma Koyama - Web page: https://patentgrep.com/patent/US10374568B2 ## CPC - H03H 1/00: Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network (constructional details of electromechanical transducers H03H9/00) - H01F 5/00: Coils (superconducting coils H01F6/06; fixed inductances of the signal type H01F17/00) - H01F 17/045: {with core of cylindric geometry and coil wound along its longitudinal axis, i.e. rod or drum core} - H01F 27/006: {with special arrangement or spacing of turns of the winding(s), e.g. to produce desired self-resonance} - H01F 27/2823: {Wires (H01F27/2866 takes precedence)} - H01F 41/069: Winding two or more wires, e.g. bifilar winding - H03H 7/427: {Common-mode filters (H02J3/01 and H02M1/126 takes precedence)} - H01F 38/48: {Common mode inductor for reducing or eliminating common mode noise on parallel lines} - H03H 2001/0021: {Constructional details} - H03H 2001/0035: {Wound magnetic core} - H03H 2001/0092: {Inductor filters, i.e. inductors whose parasitic capacitance is of relevance to consider it as filter} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract Disclosed herein is a common mode filter that includes first and second terminal electrodes provided on the first flange part, third and fourth terminal electrodes provided on the second flange part, a first wire wound around the winding core part and having one end connected to the first terminal electrode and other end connected to the third terminal electrode, and a second wire wound around the winding core part and having one end connected to the second terminal electrode and other end connected to the fourth terminal electrode. The winding core part includes a first winding region, a second winding region, and a third winding region positioned between the first and second winding regions in the axial direction. The first and second wires are bifilar-wound in the first and second winding regions and layer-wound in the third winding region. ## Claims ### Claim 1 A common mode filter comprising: a core including a winding core part extending in an axial direction, a first flange part provided at one end of the winding core part in the axial direction, and a second flange part provided at other end of the winding core part in the axial direction; first and second terminal electrodes provided on the first flange part; third and fourth terminal electrodes provided on the second flange part; a first wire wound around the winding core part and having one end connected to the first terminal electrode and other end connected to the third terminal electrode; and a second wire wound around the winding core part and having one end connected to the second terminal electrode and other end connected to the fourth terminal electrode, wherein the winding core part includes first, second, and third sections arranged in this order from the first flange part to the second flange part, wherein the first and second wires are bifilar-wound in the first section and layer-wound in each of the second and third sections, and wherein the first and second wires cross each other between the second and third sections. ### Claim 2 (depends on 1) The common mode filter as claimed in claim 1, wherein a number of turns of the first and second wires in the first section is smaller than that of the first and second wires in each of the second and third sections. ### Claim 3 (depends on 2) The common mode filter as claimed in claim 2, wherein a number of turns of the first and second wires in the second section is a same as that of the first and second wires in the third section. ### Claim 4 (depends on 1) The common mode filter as claimed in claim 1, wherein the second wire is wound on the first wire in each of the second and third sections. ### Claim 5 (depends on 1) The common mode filter as claimed in claim 1, wherein the second wire is wound on the first wire in the second section, and wherein the first wire is wound on the second wire in the third section. ### Claim 6 A common mode filter comprising: a core having first, second, and third sections, the second section being positioned between the first and third sections; and first and second wires wound around the first, second, and third sections of the core, wherein the first and second wires cross each other between the second and third sections, wherein the first and second wires are wound in parallel with each other in the first section, and wherein one of the first and second wires is wound on other of the first and second wires in the second and third sections. ### Claim 7 (depends on 6) The common mode filter as claimed in claim 6, wherein the first wire is wound on the second wire in each of the second and third sections. ### Claim 8 (depends on 6) The common mode filter as claimed in claim 6, wherein the first wire is wound on the second wire in the second section, and wherein the second wire is wound on the first wire in the third section. ### Claim 9 (depends on 6) The common mode filter as claimed in claim 6, wherein a number of turns of the first and second wires in the first section is smaller than that of the first and second wires in each of the second and third sections. ### Claim 10 (depends on 9) The common mode filter as claimed in claim 9, wherein a number of turns of the first and second wires in the second section is a same as that of the first and second wires in the third section.