Patent ID: 6664530
Filing Date: 2003-12-16
Classification: H04N

Abstract:
A CMOS active pixel for an image sensor including a photosensitive element, whose electrical charge is reset during a reset phase and read during a read phase, the photosensitive element being connected between a photosensitive node and a ground, the active pixel comprising:a first amplifier active during a reset phase, the first amplifier including: an inverter input connected to a photosensitive node; a non-inverter input connected to a first reference voltage source; and an output; a first switch and second switch connected in series, the first switch and the second switch connected between the inverter input and the output of the first amplifier, wherein the first switch is controlled by a first control signal and the second switch is controlled by a second control signal; wherein the first control signal is active during a first time period of the reset phase; wherein the second control signal is active during the first time period and a second time period of the reset phase; wherein the first control signal and the second control signals are inactive during a third time period of the reset phase and during the read phase; a capacitive feedback element parallel-mounted on the first switch; and a second amplifier mounted as a follower with an input connected to the photosensitive node and an output providing a signal representing an electrical charge of the photosensitive element during the read phase, and the second amplifier active during the read phase.