Lock-in amplifiers for AMR sensors

Díaz Michelena, Marina and Cobos Arribas, Pedro and Aroca Hernández-Ros, Claudio (2015). Lock-in amplifiers for AMR sensors. "Sensors and Actuators A: Physical" (n. 222); pp. 149-159. ISSN 0924-4247.


Title: Lock-in amplifiers for AMR sensors
  • Díaz Michelena, Marina
  • Cobos Arribas, Pedro
  • Aroca Hernández-Ros, Claudio
Item Type: Article
Título de Revista/Publicación: Sensors and Actuators A: Physical
Date: February 2015
Freetext Keywords: Magnetic sensors; AMR magnetometers; Fluxgate sensors; Low noise and temperature compensation
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Electrónica Física
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Anisotropic magnetoresistive (AMR) magnetic sensors are often chosen as the magnetic transducer for magnetic field sensing in applications with low to moderate magnetic field resolution because of the relative low mass of the sensor and their ease of use. They measure magnetic fields in the order of the Earth magnetic field (with typical sensitivities of 1‰/G or 10−2‰/μT), have typical minimum detectable fields in order of nT and even 0.1 nT but they are seriously limited by the thermal drifts due to the variation of the resistivity with temperature (∼2.5‰/°C) and the variation of the magnetoresistive effect with temperature (which affects both the sensitivity of the sensors: ∼2.7‰/°C, and the offset: ±0.5‰/°C). Therefore, for lower magnetic fields, fluxgate vector sensors are generally preferred. In the present work these limitations of AMR sensors are outlined and studied. Three methods based on lock-in amplifiers are proposed as low noise techniques. Their performance has been simulated, experimentally tested and comparatively discussed. The developed model has been also used to derive a technique for temperature compensation of AMR response. The final goal to implement these techniques in a space qualified applied specific integrated circuit (ASIC) for Mars in situ exploration with compact miniaturized magnetometers.

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Item ID: 38891
DC Identifier: http://oa.upm.es/38891/
OAI Identifier: oai:oa.upm.es:38891
Deposited by: Memoria Investigacion
Deposited on: 23 Dec 2015 18:11
Last Modified: 16 Feb 2016 12:02
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