Incremental delta-sigma modulators for temperature sensing applications

This paper presents a comparison of incremental delta-sigma analogue-to-digital converters for integrated temperature sensing applications. The characteristics of bipolar transistor-based temperature sensing front-ends place specific requirements on the modulator loop architecture. Single loop delta-sigma architecture that removes the input signal from the internal loop by the addition of a feedforward path to the quantiser has been investigated thoroughly. It is found that the Noise Transfer Function (NTF) implemented by the modulator can be optimised for either accuracy or integrator signal excursion, based on the requirements of the target application.