Design of a Sigma-Delta Interface for Heat Balanced Bolometer

This paper presents the design of a sigma-delta interface for a heat balanced bolometer. The sigma-delta interface acts both as digital readout circuit and as a mean of heat feedback. The heat balancing is based on the Electrical Substitution principle and implementation through capacitive coupling. The design from the functional block down to the layout is presented. Expected performance of the realized chip is evaluated through transistor level circuit simulation and top-simulations. The circuit is designed for a realization in AMS CMOS 0.35 µm technology operating at 3.3 V.