Method and system for implementing correlated multi-sampling with improved analog-to-digital converter linearity

摘要

A method of implementing Correlated Multi-Sampling (CMS) in an image sensor with improved analog-to-digital converter (ADC) linearity starts with an ADC circuitry included in a readout circuitry that generates a plurality of uncorrelated random numbers used as a plurality of ADC pedestals for sampling image data. A Successive Approximation Register (SAR) included in the ADC circuitry stores a different one of the ADC pedestals before each sampling of the image data. The ADC circuitry samples an image data from a row a plurality of times against plurality of ADC pedestals to obtain a plurality of sampled input data. The ADC circuitry converts each of the plurality of sampled input data from analog to digital, which includes performing a binary search using the SAR. Other embodiments are also described.

主权项

1. A method of implementing Correlated Multi-Sampling (CMS) in an image sensor with improved analog-to-digital converter (ADC) linearity, comprising:
acquiring by a readout circuitry an image data from a first row in a color pixel array; generating by an ADC circuitry included in the readout circuitry a plurality of uncorrelated random numbers used as a plurality of ADC pedestals for the first row, the ADC pedestals including a first ADC pedestal and a second ADC pedestal; storing by a Successive Approximation Register (SAR) included in the ADC circuitry the first ADC pedestal; sampling by the ADC circuitry the image data from the first row against the first ADC pedestal stored in the SAR to obtain a first sampled input data; and converting by the ADC circuitry the first sampled input data from analog to digital to obtain a first ADC output value; once the first ADC output value is obtained,
storing by the SAR the second ADC pedestal,sampling by the ADC circuitry the image data from the first row against the second ADC pedestal stored in the SAR to obtain a second sampled input data, andconverting by the ADC circuitry the second sampled input data from analog to digital to obtain a second ADC output value.