Study On High Dynamic Range CMOS Image Sensor Technique

This paper is mainly about a part of research work on a paramount project to tackle in Tianjin Science & Technology Committee "High Performance High Dynamic CMOS Image Sensor Design". CMOS image sensor integrates image accquisition devices and processing circuits on a chip with CMOS plane process, which has advantage of high integration, random access, low voltage, low power dissipasion. This project includes design of pixel, digital programmer gain amplifier, analog-to-digital convertor and timing control circuits, which is a VLSI mixed signal circuit design. Our CMOS image sensor can be widely used in safe airbag of car, the third generation mobile communication equipment, security inspection, and cameras in crepuscular. There is no report about this type of CMOS image sensor, which has very wide application background. We can has independent intelligent property right with the accomplishment of this project.During my graduate design term, I have taken part in design of CMOS image sensor system and analog chain from pixel to analog to digital convertor. This article emphases dual integration dual sampling pixel design and system optimize design. First generalizing the development of CMOS image sensor and key factors in design; based on analysis of photo photoresponse, photocurrent (drift and diffusion) collection, and read out circuit structure, combining with process parameters of CHRT corporation, constructing photo-electronic-convertion model of photodiode and simulating the . analysising multiple sampling enhancing dynamic range, and according project requirement, designing line parallel and pixel parallel dual integration dual sampling pixel structure can implement arithmetic of high dynamic range and mobile detection. Analysing relations between fill factor, processing time, power disspassion from system design structure, and construct optimizing system structure of CMOS Image Sensor.The creative work of this article include: based photodiode operation principle and process parameter of CHRT corporation construct parasitic photodiode photo-electronc-convertor SPICE model for the first time; design of dual integration two sampling pixel circuits and layout which can fulfill extending dynamic range, and motion detection with different timing control circuit. According many system parameters optimize system design. Till now, most modules of CMOS Image sensors are coming to an end and it will be manufactured in the 2004 by chrt 0.35um CMOS technology. All the design work will be ended in march of 2004.