An imaging pixel unit-cell topology leveraging a photodetector in the forward-bias region is proposed. Connecting the anode of the photodiode to the gate of a NMOS device operating in the subthreshold region provides the basis for a new open-circuit voltage pixel (VocP) architecture. Theoretical analysis is presented to show the response and performance benefits of the VocP in comparison to a conventional pixel. Based on this analysis, the signal and noise relationships for both pixels are derived and leveraged to construct an end-to-end readout system model. The model results highlight potential performance benefits of the VocP over a conventional direct-injection pixel topology. To verify the analysis, the proposed VocP readout architecture is fabricated along with a conventional direct-injection pixel readout in a $0.18~\mathrm {\mu }\text{m}$ CMOS technology. The VocP performance is compared to a traditional reverse-bias current-mode photodetector configuration. Simulation, modeling, and measurements align with the proposed analytical model. Benefits in system sensitivity and dynamic range are demonstrated showing more than a $2\times $ improvement in noise-equivalent temperature difference and a 4 dB improvement in dynamic range.

中文翻译：

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非冷却型红外图像传感器的开路电压像素的信号和噪声分析

提出了在前向偏置区域中利用光电检测器的成像像素单位晶格拓扑。将光电二极管的阳极连接到在亚阈值区域内工作的NMOS器件的栅极，为新的开路电压像素（VocP）架构提供了基础。进行了理论分析，以显示与传统像素相比VocP的响应和性能优势。基于此分析，得出两个像素的信号和噪声关系，并利用它们来构建端对端读出系统模型。模型结果突出显示了VocP相对于常规直接注入像素拓扑的潜在性能优势。为了验证分析结果，将拟议的VocP读出架构与传统的直接注入像素读出一起制作在一个 $ 0.18〜\ mathrm {\ mu} \ text {m} $ CMOS技术。将VocP性能与传统的反向偏置电流模式光电探测器配置进行了比较。仿真，建模和测量与建议的分析模型保持一致。展示了系统灵敏度和动态范围方面的优势，不仅显示出 $ 2 \次$ 等效噪声温差的改善和动态范围的4 dB改善。