Patent ID: 6731335
Filing Date: 2004-05-04
Classification: H04N

Abstract:
A method for driving a unit pixel which comprises a first photodiode for receiving light from an object and for generating and integrating photoelectric charges; a first transfer transistor coupled between the first photodiode and a single sensing node, for transferring the photoelectric charges generated in the first photodiode to the single sensing node, in response to a first control signal; a second photodiode for receiving light from the object and for generating and integrating photoelectric charges; a second transfer transistor coupled between the second photodiode and the single sensing node, for transferring the photoelectric charges generating in the second photodiode to the single sensing node, in response to a second control signal; a reset transistor coupled between a power supply and the single sensing node, for outputting the photoelectric charges stored in the single sensing node, in the response to a third control signal; a drive transistor coupled to the power supply, for acting as a source follower in response to an output of the single sensing node; and a select transistor coupled to the drive transistor, for outputting an image data driven by the drive transistor in response to address signals, the method comprising the steps of:(a) fully depleting the first and second photodiodes; (b) receiving light in the first and second photodiodes and generating photoelectric charges; (c) turning on the reset transistor, turning off the first and second transfer transistors and turning on a selector transistor, and outputting a reset voltage level through the single sensing node, the drive transistor and the select transistor; (d) turning off the reset transistor and then turning on the first transfer transistor with said reset transistor remaining off, and outputting a data voltage level of the photoelectric charges generated in the first photodiode through the single sensing node, the drive transistor and the select transistor; (e) turning on the reset transistor, turning off the first transfer transistor and outputting the reset voltage level through the single sensing node, the drive transistor and the select transistor; and (f) turning off the reset transistor and then turning on the second transfer transistor with said reset transistor remaining off, and outputting a data voltage level of the photoelectric charges generated in the second photodiode through the single sensing node, the drive transistor and the select transistor.