A readout system for pellistors with pulsed thermal feedback

Abstract

Catalytic flammable gas sensors are used for safety in places where the accumulation of flammable gasses can generate a blast. These devices measure the flammable gas concentration via the heat produced by the catalysis of the gas by a heated catalytic coating. We propose the design and implementation of a readout system based on feedback heat pulses. In the proposed system, the heat of catalysis is directly measured via its compensation by a controlled feedback heat power. Contrary to that proposed sensor operation, previous potentiometric schemes would measure a sensor temperature increase resulting from the heat of catalysis. This proposed readout scheme for so-called “pellistor” sensors is expected to improve the measurement performance while providing a simpler implementation than previous systems.