Ultra-low overhead signal acquisition circuit for capacitive and piezoelectric sensors

Driven by the defense, medical, and automotive markets, the demand for low-cost, low-overhead sensors for precision signal acquisition has increased by more than 200% since 2001. However, a growing number of sensor applications necessitate wireless operation, and, therefore, impose significant constraints on the acquisition and processing subsystems, which interface to these sensors. The goal of this work is to present a novel capacitive sensor interface circuit that is capable of accurately estimating the power in a user-defined frequency band in remarkably energy-efficient manner. This switched-capacitor-based implementation is designed in TSMCpsilas 0.35-mum mixed-mode CMOS technology and consumes a scant 30 muW, comparable to the leakage power of a 10-g Li-ion battery.