3D Ultrasonic Rangefinder on a Chip

TLDR

The chip integrates an AlN MEMS transducer array with a 0.18 µm CMOS ASIC featuring 10 independent channels, each with high‑voltage transmitters, readout amplifiers, and switched‑capacitor band‑pass ΣΔ ADCs, enabling 3‑D ultrasonic ranging over a ±45° field of view to 1 m. The device achieves sub‑millimeter accuracy (0.4 mm rms at 0.5 m) with angular errors of 0.2°/0.8°, while consuming only 400 µW at 30 fps for 1 m range and 5 µW per channel at 10 fps for 0.3 m range.

Abstract

An ultrasonic 3D rangefinder uses an array of AlN MEMS transducers and custom readout electronics to localize targets over a ±45° field of view up to 1 m away. The rms position error at 0.5 m range is 0.4 mm, 0.2 °, and 0.8 ° for the range, x-angle, and y-angle axes, respectively. The 0.18 μm CMOS ASIC comprises 10 independent channels with separate high voltage transmitters, readout amplifiers, and switched-capacitor bandpass ΣΔ ADCs with built-in continuous time anti-alias filtering. For a 1 m maximum range, power dissipation is 400 μW at 30 fps. For a 0.3 m maximum range, the power dissipation scales to 5 μW/ch at 10 fps.