An adaptive integration time CMOS image sensor with multiple readout channels for star trackers

In this work, we present an adaptive integration time CMOS image sensor with multiple readout channels for star tracker application. The sensor architecture allows each pixel to have an adaptive integration time. By cyclically selecting a row of pixels and checking the integration voltage of each pixel, brighter pixels can be “marked” and read out first. The dimmer pixels will continue integration until their voltage fall into a window defined by two threshold voltages. Each pixel only consists of five transistors. In order to improve the readout throughput and hence to reduce the rolling time, a multiple readout channel architecture is proposed. A proof-of-concept 320×128-pixel image sensor has been implemented using GlobalFoundries 0.18μm mixed-signal CMOS process.