A video graphics array (VGA) (640 $\times $ 480) indirect time-of-flight (ToF) CMOS image sensor has been designed with 4-tap 7- $\mu \text{m}$ global-shutter pixel in 65-nm back-side illumination (BSI) process. With a 4-tap pixel structure, we achieved motion artifact-free depth map. Peak current during exposure time has been reduced by current spreading with constant delay chain in the photo-gate driver. Column fixed-pattern phase noise (FPPN) from the constant delay chain is self-compensated by the proposed time-interleaving technique with the two inversely directional clock chains in the photo-gate driver. Quantum efficiency (QE) and demodulation contrast (DC) have been optimized by using appropriate optical engineering techniques with an optimal silicon thickness. As a result, QE of 34% at 940-nm near-infrared and high DC of 86% at 100-MHz modulation frequency have been achieved. In addition, motion artifact and column FPPN are successfully removed in the depth map. The proposed ToF sensor shows depth noise less than 0.57% with 940-nm illuminator over the working distance up to 4 m, and consumes only 160 mW for VGA output at 60 frames/s.

中文翻译：

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具有 4-Tap 7-μm 全局快门像素和固定模式相位噪声自补偿的 VGA 间接飞行时间 CMOS 图像传感器

一个视频图形阵列 (VGA) (640 $\times $ 480) 间接飞行时间 (ToF) CMOS 图像传感器采用 4-tap 7- $\mu \text{m}$ 65 纳米背面照明 (BSI) 工艺中的全局快门像素。通过 4-tap 像素结构，我们实现了无运动伪影的深度图。曝光时间内的峰值电流已通过光电门驱动器中恒定延迟链的电流扩展而降低。来自恒定延迟链的列固定模式相位噪声 (FPPN) 通过所提出的时间交织技术与光电门驱动器中的两个反向时钟链进行自我补偿。量子效率 (QE) 和解调对比度 (DC) 已通过使用具有最佳硅厚度的适当光学工程技术进行了优化。结果，在 940-nm 近红外波段实现了 34% 的 QE，在 100-MHz 调制频率下实现了 86% 的高 DC。此外，在深度图中成功去除了运动伪影和列 FPPN。