A Low Power Readout Mechanism with Improved Low Light Performance in CMOS Image Sensors

摘要

The power consumption of the readout path in a CMOS image sensor is dominated by the Analog-to-digital converters (ADCs). The power consumption of an ADC is decided by the maximum noise it can tolerate. The increase in tolerable noise or reduction in resolution of the ADC decreases the power consumption. In this work, a charge based readout resulting in increased quantization voltage step compared to the conventional voltage readout for a given resolution is presented. The quantization steps and the reduction in power consumption are estimated from suitable device models. The estimated results show around 20% reduction in the power consumption of ADCs.