Patent ID: 8582004

Claim:
An image sensor, comprising: a photodetector; an output transistor having a gate coupled to receive a signal from said photodetector; a reset transistor having a source terminal coupled to reset said photodetector; a sample circuit coupled to receive an output signal from said output transistor, said sample circuit including a first capacitor that has a first terminal and a second terminal and a second capacitor that has a third terminal and a fourth terminal, the first and third terminals being respectively connected to receive output signals from said output transistor; and a control circuit having: a first configuration to switch said reset transistor to a triode region such that said output transistor provides a first output signal to the first terminal to be sampled while said reset transistor is in the triode region; and a second configuration to switch said reset transistor to an OFF state such that said output transistor provides a second output signal to the third terminal to be sampled during the OFF state, wherein said control circuit selects a first voltage level for the second terminal to sample the first output signal and selects a second voltage level for the fourth terminal to sample the second output signal, wherein the second voltage level is offset from the first voltage level in a direction same as the first output signal is offset from the second output signal.