Power efficient instrumentation with 100 fA-sensitivity and 164 dB-dynamic range for wearable chronoamperometric gas sensor arrays

Chronoamperometric gas sensor arrays show great promise for ultra-low power consumption and low cost for wearable gas sensing devices for human safety and health monitoring. This paper presents a novel power efficient instrumentation circuit with high sensitivity and large dynamic range for wearable chronoamperometric gas sensor arrays. This instrumentation combines an input digital modulation technique and a semi-synchronous incremental ΣΔ ADC structure to achieve very high power efficiency over a large dynamic range with high sensitivity. The proposed instrumentation was implemented in 0.5 μm CMOS technology. Measurement results demonstrate that 164dB cross-scale dynamic range and 100 fA sensitivity are achieved with a high power efficiency.