Low-Power Printed Circuit Board Fluxgate Sensor

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A new printed circuit board flat fluxgate sensor with integrated coils and amorphous alloy core was developed and its excitation parameters optimized for low-power consumption. The power consumption achieved with 10 kHz, 300 mA p-p pulse excitation with duty cycle 12.5% was only 3.9 mW, which is three times lower than that for sinewave B excitation. The sensor sensitivity reached 94 V/T. The required excitation bridge supply voltage was only 0.47 V. The low-cost low-power sensor has a temperature offset stability of 120 nT in the <formula formulatype="inline"><tex>$-$</tex></formula>20 to <formula> <tex>$+$</tex></formula>70 <formula formulatype="inline"><tex>$^{\circ}{\hbox{C}}$</tex> </formula> temperature range and 0.17%/<formula formulatype="inline"><tex>$^{\circ}{\hbox{C}}$</tex> </formula> open-loop sensitivity tempco due to the use of a new core embedding technique. The perming error due to 10 mT field shock was suppressed below 1.2 <formula formulatype="inline"><tex>$\mu{\hbox{T}}$</tex></formula>. The short-time offset stability was 38 nT within 3 h. Thus the developed sensor is more precise and less energy consuming than a periodically flipped anisotropic magnetoresistance (AMR) sensor. The achieved parameters are sufficient for compass with 0.1<formula><tex>$^\circ$</tex></formula> error. </para>