CMOS探测器自适应信号读出技术研究

Research on Adaptive Signal Readout Technology for CMOS Detectors

摘要:

设计了一种根据光照强度自动调节增益的CMOS探测器,它能够在一帧时间内实现光照强度与积分增益自动适应,从而实现无论在弱光还是强光条件下CMOS探测器都能有适应的灵敏度和动态范围。相较于传统CTIA电路,自适应信号读出技术新增了比较器电路来控制CTIA积分电容大小,通过短曝光输出电压与参考阈值比较,输出信号结果用来调整长曝光积分增益,最终得到每个像素的输出电压和增益档位。基于 0.5 mm 5V-CMOS工艺进行了128×1线阵CMOS探测器设计仿真与流片,仿真结果表明,光电流在2 pA~100 nA六个数量级内分别自适应四个积分增益,都能有良好的信号读出。

Abstract:

An adaptive CMOS detector has been designed that automatically adjusts gain based on light intensity. The detector can automatically adjust the gain based on the intensity of light during integration, enabling it to adapt and provide suitable sensitivity and dynamic range readout in both low-light and high-light conditions. In this study, a new comparator circuit is introduced alongside the traditional CTIA circuit to control the size of the CTIA integration capacitor. By comparing the output voltage from short exposure with the reference threshold, the result is used to fine-tune the long exposure integration gain for each pixel. The design and simulation of a 128×1 linear array CMOS detector were conducted using 0.5μm 5V-CMOS technology. The simulation results demonstrate that the CMOS detector can adaptively adjust four different integration gains within a range of five orders of light intensity, covering photocurrents from 2 pA to 100 nA, while maintaining excellent signal readout performance.