Monolithic Sensor Interfaces with On-Board Digital Signal Processing

This paper describes a method to reduce the cost of interfacing to sensors despite the rise in computational complexity and the number of variables associated with modern control systems. It is based on monolithically mixing analog and digital functions that are customized to perform a specific application. This approach has the advantage of bringing signal processing close to the sensor tip which off-loads the main CPU and reduce in-system signal bandwith, power consumption and component complexity. As an example, a single chip 3-channel data acquisition system for power management applications has been successfully designed, fabricated and tested. This mixed, analog/digital single chip system is composed of three 11-bit Delta-Sigma analog-to-digital converters with an oversample clock of 3.58 MHz. The dedicated digital signal processor has 32- bit two´s complement, fixed point architecture and performs lowpass filtering, accumulation, and data comparison and selection.