A 64×64 APD-Based ToF Image Sensor with Background Light Suppression up to 200 klx Using In-Pixel Auto-Zeroing and Chopping

Abstract

This paper presents a time-of-flight (ToF) image sensor for outdoor applications. The sensor employs a gain-modulated avalanche photodiode (APD) that achieves high modulation frequency. The suppression capability of background light is greatly improved up to 200klx by using a combination of in pixel auto-zeroing and chopping. $\mathrm{A}64 \times 64$ APD-based ToF sensor is fabricated in $\mathrm{a}0.11 \mu \mathrm{m}$ CMOS. It achieves depth ranges from 0.5 to 2 m with 25MHz modulation and from 2 to 20 m with 1.56MHz modulation. For both ranges, it achieves a non-linearity below 0.8% and a precision below 3.4% at a 3D frame rate of 96fps.