Design of black level calibration system for CMOS image sensor

In this paper, a black level calibration system for CMOS image sensor is presented. By using the combination of two calibration points, the system achieves a wide calibration range and the resolution requirement of DAC's also can be decreased. The approximate strategy adopted in calculating the calibration voltage applied to the calibration point decreases the overhead of the digital circuit and the complexity of timing control. Simulation results show that the designed calibration system successfully completes the calibration process as expected.