A Low-Power Wide-Dynamic-Range Readout IC for Breath Analyzer System

Abstract-We present a low-power wide-dynamic-range readout circuit that directly interfaces a selective metal-oxide gas sensor. The proposed novel readout architecture implements an adaptive baseline compensation and limits the sensor current. The readout IC can interface the sensors with the baseline resistance from 1 kΩ to 100 MΩ and measures the gas induced resistance change in the range from 0.05% to 10% of the baseline resistance. The simulations demonstrate the 166 dB dynamic range of the readout circuit and 113 µW power consumption amenable to the sensors that can operate at room temperature for the application of the proposed system in portable breath analyzers. I. INTRODUCTION Detection and discrimination of the signaling metabolites in the exhaled breath and their measurement in the trace concentrations would lead to a personal breath analyzer, a fast, non-invasive and early diagnostic medical tool [1], There is a wide range of proposed instrumentation techniques developed for resistance measurement in the literature [3], We propose a low-complexity low-power architecture for the measurement of gas concentrations that tracks the baseline resistance. The readout circuit matches the sensor baseline resistance from 1 kΩ to 100 MΩ. The detectable resistance change ratio ranges from 0.05% to 10% of the base resistance, which leads to the dynamic range of the system of 166 dB. In addition, the power consumption of the systems is significantly reduced compared to the solutions proposed in the literature. The proposed topology is also amenable to implementation of the signal processing algorithms based on the independent component analysi