Paper

A 3.96-µm, 124dB dynamic-range, digital-pixel sensor with triple and single quantization operations for monochrome and near-infrared dual-channel global shutter operation

2025 May

Authors Ken Miyauchi*, Masayuki Uno*, Toshiyuki Isozaki*, Hideyuki Fukuhara*, Kazuya Mori*, Hirofumi Abe*, Masato Nagamatsu*, Rimon Ikeno*, Isao Takayanagi*, Hsin-Li Chen**, Chih-Hao Lin**, Wen-Chien Fu**, Shou-Gwo Wuu**, Song Chen***, Lyle Bainbridge***, Qing Chao***, Ramakrishna Chilukuri***, Wei Gao***, Andrew P. Hammond***, Tsung-Hsun Tsai***, and Chiao Liu***

IEEE Journal of Solid-State Circuits, Vol.60, No.5, pp.1771-1781, (2025)
https://ieeexplore.ieee.org/document/10706075

This article presents a 3.96-µm, 640 × 640 pixel stacked digital pixel sensor capable of capturing co-located monochrome (MONO) and near-infrared (NIR) frames simultaneously in a dual-channel global shutter (GS) operation. A super-pixel structure is proposed with diagonally arranged 2 ×2 MONO and NIR sub-pixels. To enhance visible light sensitivity, large and small non-uniform micro-lenses are formed on the MONO and NIR sub-pixels, respectively. Each floating diffusion (FD) shared super-pixel is connected to an in-pixel analog-todigital converter and two banks of 10-bit static random access memories (SRAMs) to enable the dual-channel GS operation. To achieve high dynamic range (DR) in the MONO channel, a triple-quantization (3Q) operation is performed. Furthermore, a single-channel digital-correlated double sampling (D-CDS) 3Q operation is implemented. The fabricated sensor achieved 6.2-mW low power consumption at 30 frames/s with dual-channel capture. The MONO channel achieved 124-dB DR in the 3Q operation and 60 dB for the NIR channel. The sensor fits the stringent form-factor requirement of an augmented reality headset by consolidating MONO and NIR imaging capabilities.