A CMOS-based image sensor pixel structure and application design

A CMOS image sensor (Complementary Metal-Oxide-Semiconductor) is an image sensor made using CMOS technology, which converts light signals into electrical signals to capture images. CMOS sensors integrate amplifiers and converters at each pixel, offering advantages like low power consumption and high-speed processing. They are widely used in digital cameras, smartphones, security surveillance, automotive driver assistance systems, and medical imaging. This paper begins by reviewing international research on improving CMOS image sensor quality. Building on this foundation, it proposes a CMOS photodiode model, represented as a current source and capacitor, which generates a voltage proportional to light intensity. Resetting the photodiode is essential for accurate readings. A source follower minimizes noise and stabilizes output vol image sensor design based on CoolSpice simulation. This experiment focuses on designing an image sensor with a 3x3 pixel array, consisting of photodiodes and NMOS transistors. The sensor utilizes a row-column selection circuit driven by pulsed signals for precise pixel activation. Simulation in CoolSpice shows varying output voltages for each pixel, indicating differing light intensities, with strategies suggested to reduce leakage effects. Results are visualized in an Excel spreadsheet, correlating voltage levels with light intensity. The image sensor designed in this project can read results within 60 microseconds, with a dynamic range from 0 to 652 millivolts.