Flugate Sensor With Pulse Feedback

Abstract

Fluxgate sensors have typically only 100 $\mu \text{T}$ range, which sometimes limits their applications. The main obstacle for increasing the measurement range is the power dissipated in their feedback coil. Until now, the feedback was always continuous. We suggest using pulse excitation only for the active part of the period, in which an output signal is present. In this paper, we show for the first time that if the sensor is excited by short pulses, the feedback need not be continuous, but it can be formed by the pulses slightly wider than the excitation pulses. We have shown that, in our case, the feedback current duty cycle can be only 17.25%. This means that for the same power, we can increase maximum feedback current and, thus, the range by the factor of three. We show that this can be done without compromising the sensor performance.