Active pixel sensor cell with integrating varactor and method for using such cell

摘要

An active pixel sensor cell including at least one photodiode and reset circuitry and an integrating varactor coupled to the photodiode, a method for reading out such a cell, and an image sensor including an array of such cells. The photodiode can be exposed to photons during an exposure interval to accumulate a sequence of subexposure charges at a first node of the photodiode. Each of the subexposure charges accumulates at the first node during a different subexposure interval of the exposure interval. The photodiode is reset during each of a sequence of reset intervals, each reset interval occurring before a different one of the subexposure intervals. An output signal indicative of an exposure charge accumulated at the storage node during the exposure interval can be asserted from the cell, where the exposure charge is indicative of a sum of all the subexposure charges.