Dual-mode wide-range linear CMOS interface circuit for resistive sensors

摘要

A dual-mode adaptive method to provide a wide-range linear sensing characteristic over various resistive sensors is presented. A high- mode acts as a resistance-to-digital converter without an analogue-to-digital converter (ADC), and a low- mode utilises an adaptive current source to keep the required ADC resolution below 8 bits. A prototype of the dual-mode sensor interface was fabricated in a 0.18 μm CMOS process, and its measured coverage of sensor resistance was from 750 to 1.2 MΩ. The power dissipation with a 1.8 V supply was 2.6–3.1 μW in the high- mode and 0.31–2.1 mW in the low- mode.