Thermal Sigma-Delta Modulator: A Temperature Measurement Application

In this article, we describe a thermal sigma-delta converter implementation with thermoresistive sensor for temperature measurement. The sensor was integrated to a 1-bit, first order, sigma-delta modulator in the place of the integrator and sum blocks. Part of the modulator circuit was digitally implemented by a microcontroller, which was integrated to the analog circuit part and to the NTC thermoresistive sensor. A digital filter, formed by a second order Comb filter followed by a FIR filter, was used to obtain the estimated temperature.