Patent ID: 7920194

Claim:
An imager device comprising: an array of pixels organized into a plurality of rows and columns, each pixel comprising a photosensitive element, a source follower transistor having a gate terminal coupled to an output of the photosensitive element, a row select switch coupled between a column output line and the source follower transistor, and a reset switch connected to the photosensitive element; a plurality of readout circuits, each readout circuit being associated with and coupled to a respective column of pixels, each readout circuit comprising a load transistor associated with source follower transistors in the pixels of the associated column, each readout circuit further comprising a hard reset circuit coupled to a drain of the reset transistor in the pixels of the associated column and an enabling transistor connected between the output line and the load transistor; and a controller adapted to: enable the row select switch of each pixel in a selected row to cause each pixel in the selected row to transfer a first voltage representing an amount of light impinging on a respective pixel during an integration period to the respective readout circuit, disable the row select switch of each pixel in the selected row to electrically disconnect the pixels in the selected row from the respective readout circuit, activate the hard reset circuits of the plurality of readout circuits to perform a hard reset of the pixels in the selected row, enable the reset transistor of each pixel in the selected row to perform a soft reset of the pixels in the selected row, and enable the row select switch of each pixel in the selected row to electrically connect the pixels in the selected row to the associated readout circuit and transfer a second voltage from the pixels in the selected row to the readout circuit, the second voltage representing a soft reset level for the pixels.