A readout circuit of an imager that enables analog-to-digital converters (ADCs) to be shared between columns of the imager is provided. Groups of ADCs share a single block of memory for storing signals processed by the ADCs. The ADCs process signals received from one group of columns of pixels and, at a different time, the ADCs process signals from another group of columns of pixels. While one of the signals processed from a column is being stored in a first memory bank, signals previously processed and stored in a second memory bank are being readout of the storage locations and provided downstream for further processing.

A readout circuit of an imager that enables analog-to-digital converters (ADCs) to be shared between columns of the imager is provided. Groups of ADCs share a single block of memory for storing signals processed by the ADCs. The ADCs process signals received from one group of columns of pixels and, at a different time, the ADCs process signals from another group of columns of pixels. While one of the signals processed from a column is being stored in a first memory bank, signals previously processed and stored in a second memory bank are being readout of the storage locations and provided downstream for further processing.

An image sensor circuit of various embodiments includes a pixel array with a plurality of pixel circuits arranged in a plurality of rows and a plurality of columns. Each column of the pixel array includes a corresponding first set of pixel circuits connected to output analog pixel signals to a respective first column readout line, and a corresponding second set of pixel circuits connected to output analog pixel signals to a respective second column readout line. Two or more analog-to-digital conversion circuits may be provided for each column of pixel circuits in the pixel array, and two or more rows of pixel circuits in the pixel array may be activated to output analog pixel signals to corresponding column readout lines at a same time.

A dual slope A/D converter uses two opposite sense ramps added to its differential input. The value in a digital counter is latched at the time when the two ramps intersect. This enables a more consistent switching point, allowing the amplifier to the linear over a larger part of its range.