# US 2013/0154630 A1 · Current sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154630 A1 - Document ID: US20130154630A1 - Status: Published application - Kind: A1 - Application number: 13/766,664 - Filed: 2013-02-13 - Published: 2013-06-20 - Earliest claimed: 2010-08-31 - Assignees: Alps Green Devices Co., Ltd. - Inventors: Masatoshi NOMURA; Manabu TAMURA - Web page: https://patentgrep.com/patent/US20130154630A1 ## CPC - G01R 19/257: using analogue/digital converters of the type with comparison of different reference values with the value of voltage or current, e.g. using step-by-step method - G01R 15/207: {Constructional details independent of the type of device used} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A current sensor includes: a first magnetic sensor and a second magnetic sensor; a first analog-to-digital converter which is connected to the first magnetic sensor and converts an output signal of the first magnetic sensor from an analog signal to a digital signal so as to be output; a second analog-to-digital converter which is connected to the second magnetic sensor and converts an output signal of the second magnetic sensor from an analog signal to a digital signal so as to be output; and an operation device which is connected to the first analog-to-digital converter and the second analog-to-digital converter, and outputs an operation value by subjecting the output signal of the first analog-to-digital converter and the output signal of the second analog-to-digital converter to differential operation. ## Claims ### Claim 1 A current sensor comprising: a first magnetic sensor and a second magnetic sensor which are arranged in a periphery of a current line through which a current to be measured passes and output reversed output signals due to an induction magnetic field from the current to be measured; a first analog-to-digital converter which is connected to the first magnetic sensor and converts the output signal of the first magnetic sensor from an analog signal to a digital signal so as to be output; a second analog-to-digital converter which is connected to the second magnetic sensor and converts the output signal of the second magnetic sensor from an analog signal to a digital signal so as to be output; and an operation device which is connected to the first analog-to-digital converter and the second analog-to-digital converter, and outputs an operation value by subjecting the output signal of the first analog-to-digital converter and the output signal of the second analog-to-digital converter to differential operation, wherein the operation device determines that measurement accuracy is low in a case where a difference between a variation Δ1 in an output signal O1-2 of the first analog-to-digital converter in second sampling immediately after first sampling with respect to an output signal O1-1 of the first analog-to-digital converter in the first sampling and a variation Δ2 in an output signal O2-2 of the second analog-to-digital converter in the second sampling with respect to an output signal O2-1 of the second analog-to-digital converter in the first sampling is higher than a threshold Δth. ### Claim 2 (depends on 1) The current sensor according to claim 1, wherein, in a case where it is determined that the measurement accuracy is low, an operation value in the first sampling is output as an operation value in the second sampling. ### Claim 3 (depends on 1) The current sensor according to claim 1, wherein, in a case where it is determined that the measurement accuracy is low, an error signal is output. ### Claim 4 (depends on 1) The current sensor according to claim 1, wherein, in a case where it is determined that the measurement accuracy is low, the operation device outputs a value calculated from a value obtained by multiplying a differential value between the output signal O1-2 of the first analog-to-digital converter and the output signal O2-2 of the second analog-to-digital converter by a coefficient of less than 1 during the second sampling, as an operation value in the second sampling. ### Claim 5 (depends on 1) The current sensor according to claim 1, wherein the first magnetic sensor and the second magnetic sensor are arranged to have point symmetry about the current line as a center and are arranged to have the same sensing axis direction. ### Claim 6 (depends on 1) The current sensor according to claim 1, wherein the first magnetic sensor and the second magnetic sensor are magnetic balance type sensors which each include a magnetic sensor element having characteristics being changed due to the induction magnetic field from the current to be measured and a feedback coil which generates a cancellation magnetic field that cancels the induction magnetic field. ### Claim 7 (depends on 6) The current sensor according to claim 6, wherein the magnetic sensor element is a magnetoresistance element. ### Claim 8 A current sensor comprising: a first magnetic sensor and a second magnetic sensor which are arranged in a periphery of a current line through which a current to be measured passes and output reversed output signals due to an induction magnetic field from the current to be measured; a first analog-to-digital converter which is connected to the first magnetic sensor and converts the output signal of the first magnetic sensor from an analog signal to a digital signal so as to be output; a second analog-to-digital converter which is connected to the second magnetic sensor and converts the output signal of the second magnetic sensor from an analog signal to a digital signal so as to be output; and an operation device which is connected to the first analog-to-digital converter and the second analog-to-digital converter, and outputs an operation value by subjecting the output signal of the first analog-to-digital converter and the output signal of the second analog-to-digital converter to differential operation, wherein the operation device determines that measurement accuracy is low, in a case where a variation Δ1 in an output signal O1-2 of the first analog-to-digital converter in second sampling immediately after first sampling with respect to an output signal O1-1 of the first analog-to-digital converter in the first sampling is higher than a threshold Δth and a variation Δ2 in an output signal O2-2 of the second analog-to-digital converter in the second sampling with respect to an output signal O2-1 of the second analog-to-digital converter in the first sampling is higher than the threshold Δth. ### Claim 9 (depends on 8) The current sensor according to claim 8, wherein, in a case where it is determined that the measurement accuracy is low, an operation value in the first sampling is output as an operation value in the second sampling. ### Claim 10 (depends on 8) The current sensor according to claim 8, wherein, in a case where it is determined that the measurement accuracy is low, an error signal is output. ### Claim 11 (depends on 8) The current sensor according to claim 8, wherein, in a case where it is determined that the measurement accuracy is low, the operation device outputs a value calculated from a value obtained by multiplying a differential value between the output signal O1-2 of the first analog-to-digital converter and the output signal O2-2 of the second analog-to-digital converter by a coefficient of less than 1 during the second sampling, as an operation value in the second sampling. ### Claim 12 (depends on 8) The current sensor according to claim 8, wherein the first magnetic sensor and the second magnetic sensor are arranged to have point symmetry about the current line as a center and are arranged to have the same sensing axis direction. ### Claim 13 (depends on 8) The current sensor according to claim 8, wherein the first magnetic sensor and the second magnetic sensor are magnetic balance type sensors which each include a magnetic sensor element having characteristics being changed due to the induction magnetic field from the current to be measured and a feedback coil which generates a cancellation magnetic field that cancels the induction magnetic field. ### Claim 14 (depends on 13) The current sensor according to claim 13, wherein the magnetic sensor element is a magnetoresistance element. ### Claim 15 A current sensor comprising: a first magnetic sensor and a second magnetic sensor which are arranged in a periphery of a current line through which a current to be measured passes and output reversed output signals due to an induction magnetic field from the current to be measured; a first analog-to-digital converter which is connected to the first magnetic sensor and converts the output signal of the first magnetic sensor from an analog signal to a digital signal so as to be output; a second analog-to-digital converter which is connected to the second magnetic sensor and converts the output signal of the second magnetic sensor from an analog signal to a digital signal so as to be output; and an operation device which is connected to the first analog-to-digital converter and the second analog-to-digital converter, and outputs an operation value by subjecting the output signal of the first analog-to-digital converter and the output signal of the second analog-to-digital converter to differential operation, wherein the operation device outputs, in a case where a variation Δ1 in an output signal O1-2 of the first analog-to-digital converter in second sampling immediately after first sampling with respect to an output signal O1-1 of the first analog-to-digital converter in the first sampling is higher than a threshold Δth and a variation Δ2 in an output signal O2-2 of the second analog-to-digital converter in the second sampling with respect to an output signal O2-1 of the second analog-to-digital converter in the first sampling is not higher than the threshold Δth, a value calculated from the output signal O2-2 of the second analog-to-digital converter during the second sampling as an operation value in the second sampling, and the operation device outputs, in a case where the variation Δ1 in the output signal O1-2 of the first analog-to-digital converter in the second sampling with respect to the output signal O1-1 of the first analog-to-digital converter in the first sampling is not higher than the threshold Δth and the variation Δ2 in the output signal O2-2 of the second analog-to-digital converter in the second sampling with respect to the output signal O2-1 of the second analog-to-digital converter in the first sampling is higher than the threshold Δth, a value calculated from the output signal O1-2 of the first analog-to-digital converter during the second sampling as an operation value in the second sampling. ### Claim 16 (depends on 15) The current sensor according to claim 15, wherein the first magnetic sensor and the second magnetic sensor are arranged to have point symmetry about the current line as a center and are arranged to have the same sensing axis direction. ### Claim 17 (depends on 15) The current sensor according to claim 15, wherein the first magnetic sensor and the second magnetic sensor are magnetic balance type sensors which each include a magnetic sensor element having characteristics being changed due to the induction magnetic field from the current to be measured and a feedback coil which generates a cancellation magnetic field that cancels the induction magnetic field. ### Claim 18 (depends on 17) The current sensor according to claim 17, wherein the magnetic sensor element is a magnetoresistance element.