UNIT PIXEL OF CMOS IMAGE SENSOR HAVING PN DIODE CONNECTED TO FLOATING SENSING NODE

摘要

PURPOSE: A unit pixel of CMOS image sensor having PN diode connected to floating sensing node is to decrease parasitic capacitance of the floating sensing node, thereby enhancing the dynamic range of output voltage. CONSTITUTION: A unit pixel of CMOS(Complementarily metal oxide semiconductor device) image sensor comprises: a pinned photodiode(310) for creating photogenerated charge due to an incident light from outside; a transfer transistor(320) for forming a channel between the pinned photodiode and a floating sensing node(330) in responsive to a first control signal to transfer the photogenerated charge created from the pinned photodiode into the floating sensing node; a PN diode(340) connected to the floating sensing node, for resetting charges stored in the floating sensing node; a driver transistor(350) of which gate is connected to the floating sensing node for acting as source follower and source is connected to a voltage supply terminal; and a select transistor(360) for forming a channel between drain of the driver transistor and an output terminal of a unit pixel in responsive to a second control signal.