An active pixel sensor cell array in which a partial transimpedance amplifier amplifies the output of each cell. The pixel sensor cell array comprises a plurality of pixel sensor cells and a second part of the amplifier. Each pixel sensor cell comprises a photo-sensitive element, a capacitor and a first part of an amplifier. The capacitor is coupled between a terminal of the photo-sensitive element and an output line of the cell. The capacitor is operable to provide a capacitive feedback in the pixel sensor cell. The second part of the amplifier is coupled to the output lines of a plurality of pixel sensor cells. The amplifier is configured to amplify an output signal from a cell.
CLAIM OF PRIORITY
This patent application claims priority under 35 USC .sctn.119(e) to co-assigned U.S. Provisional Patent Application Ser. No. 60/383,861, filed on May 28, 2002, which is incorporated by reference.
An image sensor having a plurality of pixels, each including a sense node; an output node; a first device, connected to the sense node, producing a signal at the sense node that is proportional to incident light intensity at the pixel; at least one select node to receive a first select signal for selecting the pixel output node from the plurality of pixels; a reset device for resetting the pixel; and a sample and hold circuit including a sample node coupled to the sense node. At least one amplifier is provided, including a first input node to receive an output signal from the output node of a selected pixel and a second input node connected to a reference voltage source provided as a reference to reset a selected pixel. An amplifier output node is connected to couple an amplifier output signal to a selected pixel's sample and hold circuit.
