Patent ID: 7262401

Claim:
An image sensor including an array of active pixel sensor cells, wherein each of the cells includes: at least one photodiode configured to be exposed to photons during an exposure interval including at least two subexposure intervals; reset circuitry coupled to the photodiode; and an integrating varactor, coupled between the photodiode and a storage node, and configured so that an exposure charge accumulates at the storage node during the exposure interval; wherein, in each of the cells, the reset circuitry is configured to reset the photodiode during each of a sequence of reset intervals, each of the reset intervals precedes a different one of the subexposure intervals, and the photodiode is configured so that a subexposure charge accumulates at the first node during each of the subexposure intervals, wherein the reset intervals are sufficiently short relative to the subexposure intervals and the varactor capacitance is sufficiently large relative to the first capacitance that the exposure charge at the end of a final one of the subexposure intervals is indicative of the sum of the subexposure charges accumulated at the first node during all the subexposure intervals.