An image sensing system is disclosed. The image sensing system includes an array of pixel circuits and a multiplexer configured to convey an output signal from a selected one of the pixel circuits. The output signal from the selected one of the plurality of pixel circuits is converted from analog to digital by a successive approximation register (SAR) analog-to-digital converter (ADC). A control circuit is provided to cause the SAR ADC power cycling with shaped power control signal. The SAR ADC comparator pre-amp with integrate-reset causes reduced power to the theoretical limit for imaging systems. The control circuit causes quantization process of selected ones of the pixel circuits to be repeated one or more times during the processing.