Patent ID: 8629928
Filing Date: 2014-01-14
Classification: H01L,H04N

Abstract:
1. A method for reset noise compensation, the method comprises: resetting a photodiode of the pixel by activating a first transistor coupled to the photodiode at a first node; setting a voltage of a second node to a predefined value by activating a third transistor that couples the second node to a first conductor that is coupled to a voltage source; deactivating the first transistor and activating a second transistor that is coupled between the first node and the second node; deactivating the third transistor and measuring the voltage of the second node to provide a measurement result, by activating a fourth transistor and a fifth transistor, wherein the fourth transistor is coupled to the second node and to the fifth transistor and wherein the first transistor is coupled to the first conductor; evaluating, based upon the measurement result, the predefined value and a gain factor, a value of a compensation signal to be provided to a feedback node that is coupled to the second node via a feedback capacitor; wherein the gain factor is indicative of a ratio between changes in a voltage of the feedback node and changes induced in the voltage of the second node as a result of the changes in the voltage of the feedback node; and providing the compensation signal to the feedback node.