Gain and Offset Error Correction for CMOS Image Sensor Using Delta-Sigma Modulation

摘要

A delta-sigma modulation analog-to-digital converter (ADC) has many benefits over the use of a pipeline ADC in a CMOS image sensor. These benefits include lower power, noise reduction, ease of maximizing the input range, and simpler signal routing for large arrays. Multiple delta-sigma modulation ADCs are required in a CMOS image sensor, one for each pixel column. Any voltage threshold mismatch between ADCs will introduce gain and offset errors in the ADCu27s transfer function. These errors will lead to fixed-pattern noise. Correcting gain and offset error for every ADCs in the image sensor will require a complex digital signal processor. This thesis presents techniques to minimize the effects of gain and offset errors in delta-sigma modulation ADCs for CMOS image sensors.