CMOS Pixel Photodiode: Principles and Applications

This lecture discusses the principles of CMOS pixel photodiodes, focusing on their operation in camera systems. The instructor begins by explaining the structure of a CMOS camera pixel, likening it to a PN diode similar to a solar cell. The effects of illumination on the depletion region and voltage are analyzed, highlighting how electron-hole pairs are generated and how they influence the diode's behavior. The lecture compares the operation of a solar cell under illumination with that of a CMOS pixel, emphasizing the differences in bias voltage and resulting signal. The instructor details the integration of photo current in the depletion region and the implications for image capture in cameras. The discussion includes the importance of selection mechanisms for reading pixel data and the optimization of integration and measurement times for effective camera performance. Overall, the lecture provides a comprehensive overview of the functionality and significance of CMOS pixel photodiodes in optical detection applications.