# US 2015/0177286 A1 · Current sensor, current measuring module, and smart meter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0177286 A1 - Document ID: US20150177286A1 - Status: Published application - Kind: A1 - Application number: 14/582,769 - Filed: 2014-12-24 - Published: 2015-06-25 - Earliest claimed: 2013-12-25 - Applicants: Kabushiki Kaisha Toshiba - Inventors: Yoshihiko FUJI; Hideaki FUKUZAWA; Yoshihiro HIGASHI; Tetsuro WAMURA; Motomichi SHIBANO - Web page: https://patentgrep.com/patent/US20150177286A1 ## CPC - G01R 19/0092: {Measuring current only} - G01R 15/205: {using magneto-resistance devices, e.g. field plates} - G01R 22/06: by electronic methods - G01R 33/0005: {Geometrical arrangement of magnetic sensor elements; Apparatus combining different magnetic sensor types (G01R33/0206 takes precedence)} - G01R 33/09: Magnetoresistive devices - G01R 33/091: {Constructional adaptation of the sensor to specific applications} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A current sensor comprises a plurality of magnetoresistance elements and a first magnetic body. The plurality of magnetoresistance elements each have their resistance value change by being applied with an current-induced magnetic field from a current to be measured. The first magnetic body applies a first offset magnetic field substantially parallel to the current-induced magnetic field applied to a first magnetoresistance element of the plurality of magnetoresistance elements. Moreover, a smart meter according to an embodiment of the present invention has, for example, the current sensor according to the present embodiment installed therein. ## Claims ### Claim 1 A current sensor, comprising: a plurality of magnetoresistance elements whose resistance value changes by application of an current-induced magnetic field from a current to be measured; and a first magnetic body that applies a first offset magnetic field substantially parallel to the current-induced magnetic field applied to a first magnetoresistance element of the plurality of magnetoresistance elements. ### Claim 2 (depends on 1) The current sensor according to claim 1, wherein magnetization of the first magnetic body is fixed substantially parallel to the current-induced magnetic field. ### Claim 3 (depends on 1) The current sensor according to claim 1, further comprising: a second magnetic body that applies a second offset magnetic field substantially parallel to the current-induced magnetic field applied to a second magnetoresistance element different from the first magnetoresistance element of the plurality of magnetoresistance elements, wherein the first offset magnetic field and the second offset magnetic field are different. ### Claim 4 (depends on 3) The current sensor according to claim 3, wherein a distance of the first magnetic body from the first magnetoresistance element is different from a distance of the second magnetic body from the second magnetoresistance element. ### Claim 5 (depends on 3) The current sensor according to claim 3, wherein a magnetic volume of the first magnetic body is different from a magnetic volume of the second magnetic body. ### Claim 6 (depends on 3) The current sensor according to claim 3, wherein area of the first magnetic body is different from area of the second magnetic body. ### Claim 7 (depends on 1) The current sensor according to claim 1, wherein the first magnetic body applies a second offset magnetic field substantially parallel to the current-induced magnetic field applied to a second magnetoresistance element different from the first magnetoresistance element of the plurality of magnetoresistance elements, and the first offset magnetic field and the second offset magnetic field are different. ### Claim 8 (depends on 7) The current sensor according to claim 7, wherein a distance of the first magnetic body from the first magnetoresistance element is different from a distance of the first magnetic body from the second magnetoresistance element. ### Claim 9 (depends on 7) The current sensor according to claim 7, wherein a dimension of the first magnetic body adjacent to the first magnetoresistance element in a direction of the current-induced magnetic field applied to the first magnetoresistance element is different from a dimension of the first magnetic body adjacent to the second magnetoresistance element in a direction of the current-induced magnetic field applied to the second magnetoresistance element. ### Claim 10 (depends on 1) The current sensor according to claim 1, wherein the plurality of magnetoresistance elements each include: a first magnetic layer whose magnetization direction changes with respect to the current-induced magnetic field; a second magnetic layer; a first intermediate layer provided between the first magnetic layer and the second magnetic layer; and a pair of electrode layers, and the first magnetic body is provided between one of the electrode layers and the first magnetic layer in the first magnetoresistance element. ### Claim 11 (depends on 1) The current sensor according to claim 1, wherein the first magnetic body includes a hard ferromagnetic material. ### Claim 12 (depends on 11) The current sensor according to claim 11, wherein the hard ferromagnetic material is configured from a first alloy which is any alloy selected from Co—Pt, Fe—Pt, Co—Pd, and Fe—Pd, or a material that has an additional element added to the first alloy. ### Claim 13 (depends on 1) The current sensor according to claim 1, wherein a direction of magnetization of the first magnetic body is fixed by an antiferromagnetic layer. ### Claim 14 (depends on 13) The current sensor according to claim 13, wherein the antiferromagnetic layer is configured from a second alloy which is any alloy selected from Ir—Mn, Pt—Mn, Pd—Pt—Mn, Ru—Mn, Rh—Mn, Ru—Rh—Mn, Fe—Mn, Ni—Mn, and Cr—Mn—Pt, or a material that has an additional element added to the second alloy. ### Claim 15 (depends on 1) The current sensor according to claim 1, wherein of a plurality of different output signals obtained from the plurality of magnetoresistance elements with respect to the current-induced magnetic field, an output signal indicating an appropriate output signal is selected and outputted. ### Claim 16 A current measuring module, comprising: an electronic substrate module; a current sensor fixed on the electronic substrate module; and a wiring line whose relative position to the electronic substrate module is fixed, a current to be measured flowing in the wiring line, the current sensor further comprising: a plurality of magnetoresistance elements whose resistance value changes by application of an current-induced magnetic field from a current to be measured; and a first magnetic body that applies a first offset magnetic field substantially parallel to the current-induced magnetic field applied to a first magnetoresistance element of the plurality of magnetoresistance elements. ### Claim 17 A smart meter in which the current measuring module is installed, the current measuring module comprising: an electronic substrate module; a current sensor fixed on the electronic substrate module; and a wiring line whose relative position to the electronic substrate module is fixed, a current to be measured flowing in the wiring line, the current sensor further comprising: a plurality of magnetoresistance elements whose resistance value changes by application of an current-induced magnetic field from a current to be measured; and a first magnetic body that applies a first offset magnetic field substantially parallel to the current-induced magnetic field applied to a first magnetoresistance element of the plurality of magnetoresistance elements.