Analysis and Performance Verification of an Efficient Digital Converter for Resistive Sensors
K Elangovan, C. S. Anoop · 2018
This paper proposes a linear digital electronic circuit for resistive sensors. The presented scheme translates the change in sensor resistance to a change in equivalent time-period of a pulse wave. Then, the time period is measured using a simple digital unit. The scheme is simple and it is immune to the effects of many non-ideal parameters including the drift of the capacitor, switch resistances, mismatch of op-amp saturation voltages. The working principle and theoretical error evaluation of the proposed circuit is established in the paper. Further evaluation is carried using simulation as well as experimental studies. These studies show that the scheme has a linear transfer characteristic, with non-linearity as low as 0.1%. Then, a resistive sensor, based on giant-magneto-resistance technique, is selected and interfaced with the developed circuit. The results obtained from these interfacing studies are also described in the paper.