A Digital Signal-Conditioner for Resistive Sensors and its Utility for Linearizing GMR-based Magnetometer

In this paper, a novel relaxation-oscillator based resistance to digital converter is proposed. The converter processes the resistive sensors with a circuit employing a single reference voltage and possesses low execution time. The circuit is simple and it provides many advantages like independence from amplifier gain, switch resistance, etc. The performance of the circuit is simulated and emulated for different types of resistive sensor configurations, and results are presented in this paper. The maximum nonlinearity observed from the above studies is 0.2 %. The possible error sources are brought out to show the accuracy of the proposed work. Finally, the proposed circuit is interfaced with the commercially available GMR sensor to develop a GMR-based magnetometer. Results show that the proposed circuit provides better performance than the existing works.