A 1.41µW Motion Sensing Front-End for Passive Infrared Sensors

This paper presents an integrated ultra-low power (ULP) analog front-end (AFE) for motion sensing applications with off-the-shelf passive infrared (PIR) sensors. Existing PIR-sensor-based motion sensing systems suffer from high power consumption due to the large power overhead of the sensor as well as the analog processing circuitry. In this work, a novel discrete-time signal processing approach is proposed to enable aggressive duty cycling of the PIR sensor, reducing the sensor’s average power by 1944x (from 175µW to 90nW). The AFE is fabricated in 180nm CMOS and consumes 1.41µW. This work is the first integrated ULP motion sensing front-end for PIR sensors.