Abstract
In this thesis, noise-reduction of a comparator in a CMOS image sensor design is investigated. This comparator is low-cost and offset-free. The charge injection noise is the only issue that needs to be addressed, because it reduces the resolution of the comparator significantly. Our investigation shows that the charge injection noise can be alleviated significantly by simply sizing the transistors inside this comparator properly. We propose two methods to search for the optimal size: (1) exhaustive method and (2) screening method. An Analog-To-Digital Converter (ADC) incorporating this comparator in a CMOS image sensor design is used as a vehicle to demonstrate the effectiveness. Experimental results show that this methodology does serve as a valuable design aid that can boost the resolution of our image sensor to a desired level.