Modulador sigma-delta térmico: modelagem, simulação e concepção.

Abstract

The thermo-resistive sensors are part of a series of components sensitive to temperature, which are widely used in the field of electronic instrumentation. Among these applications, there are meters of physical quantities using the principle of equivalence and its power based on the modulation sigma-delta (ΣΔ), where the sensor is part of the feedback loop of the structure. Some reasons for the use of ΣΔ modulator in electrical engineering are: the reduction of analog circuits, high resolution and high signal-to-noise ratio. In this thesis, we present the design of a measurement system based on ΣΔ modulation that uses the thermo-resistive sensor as an integrator and a comparator. The architecture of the proposed system allows the introduction of measurement of physical quantities that interact with the sensor: the temperature, thermal radiation and wind speed. Procedures are presented for the specifications required for development in VHDL-AMS. After verifying the feasibility of the functional architecture, the ΣΔ modulator is designed in terms of transistors in the design of their layout, using a TSMC 0,35 CMOS technology. The simulation results are presented to demonstrate the validity of the theoretical study carried out, which shows the correlation between the results of the functional model (VHDL-AMS), the electric model and the equations developed.