Smart sensor interface electronics

The paper reviews the architecture and design of low-cost high-performance sensor systems. These systems consist of a number of multiplexed sensor elements, sensor-specific front ends, modifiers and microcontroller or digital signal processors (DSPs). The object-oriented design approach is introduced as an approach to design low-cost high-performance systems. Constraints for the excitation signals of sensing elements are discussed and it is shown how a selective detection of the measurand can be obtained, with a high immunity for parasitic components, interfering signals and parameter drift. A set-up is presented in which the analog sensor signals are converted to analog signals in the time domain, using period-modulated oscillators. The A/D conversion of the time-domain signal can be implemented in the microcontroller or DSP. It is shown that, also in this case, the principles of the sigma-delta converters can be applied. Two case studies for systems designs are discussed: a universal sensor interface and a dynamic voltage processor.