A High Dynamic Range CMOS Image Sensor With Dual-Exposure Charge Subtraction Scheme

In this paper, we present a CMOS image sensor for star centroid measurement for the application of star trackers. We propose a new capacitive transimpedance amplifier pixel architecture with in-pixel charge subtraction scheme. The pixel is able to achieve high signal-to-noise ratio for dim stars and, at the same time, to avoid saturation for bright stars. A prototype sensor was fabricated using Global Foundry 65-nm mixed-signal CMOS process. Experimental results show that the sensor can achieve 3.8 V/lux·s and 12 dB extension of dynamic range. For the saturated star in conventional method, the centroiding accuracy is improved by over 0.1 pixels after performing charge subtraction.