Circuit and method for rapid reading of an image cell

Abstract

A circuitry for high-speed reading of a video cell for a video pickup chip including a plurality of such video cells disposed in the form of a two-dimensional array, and a read-out logic designed for imaging a high input signal dynamic volume onto a reduced output signal dynamic volume, wherein the photosensitive element of the video cell is connected to the first main electrode of a first MOS transistor (M0) and to the gate of a second MOS transistor (M1) such that the gate and the other main electrode of the first MOS transistor (M0) are short-circuited and applied to an invariable potential (Vpp) so as to achieve a logarithmic characteristic line, and that an output signal amplifier is connected to the second main electrode of the second MOS transistor (M1). Moreover, a method of high speed reading of this video cell is described. The invention excels itself by the provision that a further MOS transistor (Mr1) of the same charge carrier type, which is connected in parallel with the first MOS transistor (M0), is provided and has a main electrode short-circuited to the first main electrode of the first MOS transistor (M0), and that a reset voltage pulse is applicable to the gate electrode of this further MOS transistor (Mr1).

Dependencies are inferred from the claim text.