Capacitance DAC multi-column shared SAR/SS column parallel ADC and application

Abstract

According to the capacitor DAC multi-column shared SAR / SS-column parallel ADC and application, an A / D conversion process is divided into a coarse quantization stage and a fine quantization stage, an SAR mode is adopted in coarse quantization, an SS mode is adopted in fine quantization, the SAR process is shared by multiple columns, the SS process is shared by all columns, a capacitor array in the SAR can get rid of the limitation of single-column width, and therefore the capacity of the ADC is improved. The conversion rate is improved while higher resolution is achieved. The digital correlated double sampling is realized by multiplexing the SS for low-order quantization for quantization of a reset signal, integrally quantizing an integral signal by SAR / SS, and multiplexing a counter in the quantization process of the reset signal and a counter in low-order fine quantization in the quantization of the integral signal to directly obtain the digital correlated double sampling. According to the invention, SAR / SS ADC is realized under a small column width, a low-order SS structure is used for resetting signal quantization to directly complete digital correlation double sampling, and extra circuits and processing time are not needed.

Description

technical field [0001] The invention belongs to the technical field of read-out conversion circuits for CMOS image sensors, and in particular relates to a parallel ADC of capacitive DACs shared by multiple columns of SAR / SS columns. The invention also relates to a method for performing parallel data conversion of image sensor columns by using capacitor DAC multiple columns to share SAR / SS column parallel ADC. The present invention also relates to a method for digital correlated double sampling of an image sensor by using a capacitor DAC multiple columns to share a SAR / SS column parallel ADC. Background technique [0002] With the continuous development of CMOS process level and design technology, the performance of CMOS image sensors has been greatly improved. Its advantages in power consumption, cost, and ease of integration make it almost completely occupy the field of consumer electronics products, and it is widely used in high-end applications. also showed strong compet...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a capacitor DAC multi-column shared SAR / SS column parallel ADC, which solves the problem that the small column width limits the column parallel conversion circuit

Images