A high precision dac for cmos image sensor

Abstract

The present invention provides a high-precision DAC for a CMOS image sensor, including M-bit high-bit conversion and (K-M) low-bit conversion, and high-bit high-reference output buffering and high-bit low-reference output buffering; M-bit high-bit conversion The output provides 2 K The high reference output and low reference output of each interval, the high reference output and low reference output of each interval are respectively connected to the analog reference terminal of the low conversion through the corresponding high high reference output buffer and high low reference output buffer to provide an analog reference voltage, The output after conversion of the low bit is the final analog output. The invention realizes the area and power consumption optimization of the multi-channel high-precision DAC, eliminates the voltage mutation problem in the high-low switching process, solves the non-monotonic problem of the high-precision DAC, and ensures the black level correction of the CMOS image sensor. Uniformity of column fixed graphics noise correction.

Description

technical field [0001] The invention relates to a CMOS image sensor, in particular to a high-precision DAC for the CMOS image sensor. Background technique [0002] In recent years, with the continuous development of CMOS manufacturing technology, its advantages such as low cost, fast speed, on-chip integrated image processing unit, strong radiation resistance, and low power consumption have gradually emerged, and the imaging quality has also steadily improved. Markets, such as high-definition cameras, SLR cameras, mobile phones and other fields have replaced CCD and occupy the mainstream position. Its applications have also begun to expand from the civilian market to the aerospace field. Some domestic scientific research institutions have begun to try to use large-area CMOS detectors to replace traditional linear array CCDs as the main detectors for space detection. [0003] For the ultra-large area array CMOS image sensor mainly based on the column-level readout method, du...

AI Technical Summary

Problems solved by technology

Generally, it can be realized by configurable DAC technology, but in order to realize the black level correction of all pixels and the fixed pattern noise correction between channels and column levels, multiple DACs are required, which seriously increases the area and power consumption overhead.

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