An Adaptive Integration Time CMOS Image Sensor With Multiple Readout Channels

In this paper, 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. Through cyclically selecting a row of pixels and checking the integration voltage of each pixel, brighter pixels can be marked and readout first. Those dimmer pixels will continue integration until their voltage fall into a window defined by two threshold voltages. Each pixel only consists of five transistors. 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 was implemented using Global Foundries 0.18 μm mixed-signal CMOS process.