Mixed signal temperature control circuit for on-chip CMOS gas sensor

This paper describes a mixed signal approach to micro-hotplate temperature control technique using digital On-off control logic. The novel micro-hotplate used for this purpose is based on standard 600nm CMOS technology and contains a metal micro-heater, a (parasitic) bipolar transistor temperature sensor and an interdigitated electrode in a dielectric membrane. The micro-hotplate and the mixed-signal controller circuit are integrated on a single chip. Typically such micro-hotplate are used in MEMS gas sensing application where we believe on-chip integration will enable accurate temperature monitoring and control with the added benefit of producing low power, low cost gas sensors.