A Portable Low-Voltage Low-Power ppm-Level Resistive Sensor Measurement System

Abstract

Objective:The objective of the paper is to present a novel systematic approach for the design and development of a portable, low-voltage low-power resistive sensor measurement system with high sensitivity. The goal of the proposed system is to be able to measure the$\Delta {R}/{R}_{s}$for a wide range of baseline resistance of sensor${R}_{s}$($1 {k}\Omega $to$1 {M}\Omega $i.e. 3 orders of magnitude) with high resolution and programmable sensitivity.Method:An auto-calibrated resistive sensor interface using a novel half-bridge based circuit is presented. The square-wave excitation and square-wave demodulation technique are utilised to reduce the power consumption of the proposed technique. Moreover, the sensitivity of the system is fully auto-calibrated for a wide range of base resistors.Results:With a supply voltage of 3.3 V and bandwidth of 10 Hz, the developed system is able to measure a minimum$\Delta {R}/{R}_{s}$of about 20 ppm for$100 {k}\Omega $base resistance. Overall, the power consumption of the developed system is 36.3 mW (for four channels).Significance:The system is useful for low-voltage low-power sensor nodes as a highly sensitive readout for the resistive sensor arrays. In addition, the developed system is useful for the stain sensors in the development of flexible hybrid electronics for wearable applications.