Patent ID: 7969493

Claim:
An imaging device, comprising: a photosensor configured to receive a dosage of radiation and to produce, at an output terminal of the photosensor, an analog signal having a magnitude corresponding to an intensity of the dosage; and a comparator including a first transistor and a second transistor, each having a channel coupled in series with the other, wherein: the comparator is configured to receive, at a gate terminal of the first transistor, the analog signal in a first time frame and a reference signal in a second time frame; a gate terminal of the second transistor is coupled to a source terminal of the second transistor via a capacitor; the second time frame is different from the first time frame; and the comparator further comprises an output terminal coupled to the first and second transistors, and wherein the comparator is further configured to generate, at the output terminal and during the second time frame, an output signal corresponding to the intensity of the dosage.