A Digital Readout Suitable for Resistive Sensors Affected with a Parasitic Capacitance Element
K Elangovan, C. S. Anoop · 2021
A simple digital readout circuit suitable for resistive sensors proposed in this article. The output of the readout is proportional to the sensor resistance and independent of the parasitic capacitance of the sensor. In addition, the proposed readout circuit has the merits of (i) independence from switch resistances and drift of capacitor, (ii) no requirement of an explicit control unit, and (iii) usage of a single conversion cycle. Initially, the performance of the readout is verified using simulation studies. The maximum nonlinearity is obtained as 0.05 %. Later, the effect of the non-idealities on the readout circuit is also tested and the ensuing worst-case relative error is 0.26 %. Finally, the circuit behavior is tested experimentally with a resistive sensor and the performance is validated.