Digital pixel sensor (DPS) has evolved as a pivotal component in modern imaging systems and has the potential to revolutionize various fields such as medical imaging, astronomy, surveillance, IoT devices, etc. Compared to analog pixel sensors, the DPS offers high speed and good image quality. However, the introduced intrinsic complexity within each pixel, primarily attributed to the accommodation of the ADC circuit, engenders a substantial increase in the pixel pitch. Unfortunately, such a pronounced escalation in pixel pitch drastically undermines the feasibility of achieving high-density integration, which is an obstacle that significantly narrows down the field of potential applications. Nonetheless, designing compact conversion circuits along with strategic integration of 3D architectural paradigms can be a potential remedy to the prevailing situation. This review article presents a comprehensive overview of the vast area of DPS technology. The operating principles, advantages, and challenges of different types of DPS circuits have been analyzed. We categorize the schemes into several categories based on ADC operation. A comparative study based on different performance metrics has also been showcased for a well-rounded understanding.

翻译：数字像素传感器（DPS）已成为现代成像系统中的关键组成部分，并有望在医学成像、天文学、监控、物联网设备等领域引发革命性变革。相较于模拟像素传感器，DPS具备高速和良好图像质量的优势。然而，每个像素内部引入的固有复杂度（主要归因于模数转换器电路的集成）导致像素间距显著增大。不幸的是，像素间距的急剧增加严重阻碍了高密度集成的可行性，这一瓶颈显著限制了其潜在应用范围。尽管如此，设计紧凑型转换电路并结合三维架构范式的战略集成，可成为当前局面的潜在解决方案。本综述文章全面概述了DPS技术的广阔领域，分析了不同类型DPS电路的工作原理、优势与挑战。我们根据模数转换操作将方案分为若干类别，并基于不同性能指标进行了对比研究，以促进全面理解。