Wide input range readout IC for efficient signal extraction in gas sensor systems

This work presents a novel wide input range (WIR) readout integrated circuit (ROIC) designed for gas sensor applications. The proposed ROIC effectively doubles the input range of conventional single-slope analog-to-digital converter (SS-ADC) by incorporating an additional most significant bit (MSB) conversion phase. This enhancement enables accurate signal extraction from highly variable gas sensor outputs. The ROIC also integrates an innovative AC-coupling input network to handle slow response characteristics without increasing the AC-coupling capacitor size. The proposed ROIC can operate in two modes: normal and WIR mode. It dynamically adapts to signal variations, ensuring robust performance under varying environmental conditions without the need for complex post-processing. The WIR ROIC offers a practical and efficient solution for enhancing the dynamic range of gas sensor systems while maintaining the inherent sensitivity of the gas sensors. The prototype ROIC was fabricated using a 180 nm standard CMOS process, exhibiting a total power consumption of about 1.51 mW at a conversion rate of 62.5 kHz. The proposed design achieves competitive figure of merits: 19.6pJ/Step and 151.48 dB, indicating superior performance compared to state-of-the-art designs.