Design of Resistance to Frequency Converter for Gas Sensing Applications

This article focuses on the design and analysis of a Resistance-to-Frequency (R-F) converter intended for gas sensing applications. The proposed R-F converter utilizes a resistance controlled oscillator (RCO) implemented in 65 nm CMOS technology. Key considerations include accuracy, power consumption, compactness, and linearity of the circuit design. The Schmitt trigger was specifically enhanced to reduce power consumption while maintaining minimal non-linearity across the entire resistance range. The achieved results demonstrate a non-linearity of 0.1%, a dynamic range of 140 dB, and a power consumption ranging from 15.47µW to 27.76µW for resistance values spanning from 100kΩ to 1GΩ.