A Low-Depth-Noise Indirect Time-of-Flight CMOS Image Sensor With Tap-Rotating Technique for Extended Range and Enhanced Imaging Quality

An indirect time-of-flight (iToF) CMOS image sensor (CIS) has been designed with 65-nm pixel-level stacked backside-illuminated (BSI) CIS technology. By using an adaptable tap for ambient light detection, the sensor achieves a good balance between the depth noise and the detection range. The residual error caused by the mismatch among different taps is further reduced by a dedicated tap-rotating technique. It also features a multimachine interference suppression (MMIS) technique to further improve imaging quality. The sensor achieves a 0.29% depth noise over a 7-m detection range and 68-dB dynamic range with tap-rotating technique, while consuming only 80 mW of power.