International audienceThis paper presents a single-loop 2nd order sigmadelta interface circuit for a bolometer operating in closed-loop mode. Switched capacitor circuitry is developed to implement the sigma-delta structure. The sigma-delta modulator acts both as digital readout circuit and as a mean of heat feedback. The design approach of the sigma-delta structure and the feedback shaping is explained. The circuit is designed for a realization in AMS CMOS 0.35μm technology
