A mixed-mode temperature control circuit for gas sensors

A mixed-mode temperature control system for gas sensors is described in this work. It has been designed to be capable of controlling different gas sensor structures. The temperature range and accuracy depend on the gas sensor structure but are usually in the range of from room temperature up to 600/spl deg/C within 1/spl deg/C accuracy. The circuit has been designed with 0.8 /spl mu/m HV CMOS AMS technology in order to support the 15 V biasing voltage that is necessary to reach these high temperatures. A serial peripheral interface communication port allows real time monitoring of the heater resistance. It also allows setting of the parameters of the control and temperature reference.