Design of weak signal detection circuit of CMOS detector with large dynamic range by twice sampling method

In the field of detecting weak signals with large dynamic range, CMOS image sensor, as an optical sensor component, has the advantages of large dynamic range and wide spectral response range, and is often used to detect weak signals. The commercial CMOS image sensor system usually adopts the ADC with 16-bit accuracy, which can not satisfy the detection of weak signal in some cases. In this study, CMOS image sensor S10122 chip from Hammatsu company of Japan was used as the core device. ADI company’s 16-bit ADC chip LTC2182 and 16-bit DAC chip LTC1668 were used. The circuit was designed according to twice sampling principles to improve ADC accuracy. The results show that the accuracy of ADC can be improved from 16 to 18 bits under certain conditions.