An Interfacing Circuit for Differential Measurement of Chalcogenide-Based Resistive Gas Sensors

Low‐power temperature‐independent CMOS measurement circuits for resistive gas sensors

“…Design #2 is shown in Figure 4. This design consists of a Wheatstone bridge with common-mode feedback (CMFB) connected to the gas sensors 6 ; an operational transconductance amplifier (OTA) which transforms the bridge's output voltage into a current; a translinear circuit which computes the inverse of the current produced by the OTA; and finally, a square wave generator similar to the one from Design #1 but without an amplifier. The amplifier can be avoided since we do not need to fix the input voltage from the integrator.…”

“…Strategies based on differential measurements are studied to reduce undesired drifts in the sensors due to ambient temperature variations. 6 Besides, the circuits tolerate a wide range of input resistances 7 in order to accept different sensing materials. This is thanks to the feedback approach used to bias the sensors.…”

“…For this reason, we take special care to use temperature compensated methods for carrying out the measurements. Strategies based on differential measurements are studied to reduce undesired drifts in the sensors due to ambient temperature variations 6 . Besides, the circuits tolerate a wide range of input resistances 7 in order to accept different sensing materials.…”