Performance Evaluation of Dual-Slope Digitizer for Self-Heating Compensation in Resistive Sensor

Abstract

This study addresses the prevalent issue of self-heating (S-H) error observed in resistive sensors$(R_{X})$when integrated with electronic circuits to produce output signals. An efficient digitizer circuit is proposed to interface$R_{X}$and compensate for the S-H error. The circuit employs a dual-slope integrator and a comparator to generate a time sequence output signal. The input current through$R_{X}$is maintained in the microampere range to minimize the S-H error. Additionally, a T-network is connected to the integrating capacitor to amplify the feedback path’s incoming current. The digitizer is tested for measuring in a wide range of$R_{X} 3.63$–488.2$\text{k}\Omega $, with corresponding power dissipation of 0.273 mW–$2.05 ~\mu \text{W}$, respectively. The current through$R_{X}$ranges from 274.59 to$2.05 ~\mu \text{A}$, and with the current boosting technique (gain ranging from 21.68 to 50.22), it requires a measurement time of 4.73–382.39 ms. This scheme reduces power dissipation by 472.6–1294.94 times compared to existing techniques, signifying a noteworthy improvement. The proposed digitizer produces accurate results with an average error of ±0.56% in experiments where negligible S-H is observed in testing.