An embodiment circuit includes a first source follower configured to be controlled by a voltage at a first node, a photodiode controllably coupled to the first node, and a bias transistor configured to be controlled by a bias voltage. The bias transistor has a first terminal coupled to an output of the first source follower. The circuit additionally includes a storage node controllably coupled to the output of the first source follower, and an amplifier controllably coupled between the storage node and an output line. Also included in the circuit is a controllable switching element configured to couple a second terminal of the bias transistor to a supply voltage in response to a pixel operating in a first mode, and to couple the second terminal of the bias transistor to the output line in response to the pixel operating in a second mode.
