Patent ID: 7659500
Filing Date: 2010-02-09
Classification: H04N

Abstract:
1. An image sensor comprising: an array of pixels arranged in rows and columns; a reference current source; a transistor coupled as a source follower to said reference current source and defining one half of a current mirror, said transistor having a conduction terminal; a plurality of current sources each coupled to a column of pixels and each current source defining the other half of the current mirror and thereby mirroring the reference current source; a first common node coupled to said plurality of current sources; a second common node; at least one first resistor coupled between said first common node and said second common node; at least one second resistor coupled in series between said second common node and the conduction terminal of said transistor; and a plurality of switches selectively operable to short circuit at least one of the at least one first resistor and the at least one second resistor so as to allow more than two levels of current to be provided by said plurality of current sources.