Wide range resistance to current conversion circuit for resistive gas sensors applications

Due to their physical principle of operation, resistive gas sensors require very wide range interface circuit. Thus, to design the integrated read out solution, the accuracy in the converted data should be preserved. In this paper, a wide range resistance to current conversion circuit for gas sensing applications is designed. High linear current mirror in push pull configuration is implemented as well. Simulation results show that the circuit achieves a percentage error in the converted current between 0.12% and 0.25% over 7 decades for the sensor's resistance ranging from 100Ω to 1GΩ. The current mirror achieves an absolute percentage gain factor error of 0.2% and 0.46% for PMOS and NMOS current mirrors respectively.