Patent ID: 7167200

Claim:
A circuit for reducing oversaturation effects within CMOS image sensors, comprising: a first pixel that is configured to store during an initialization period a charge that is associated with a first reference voltage, to integrate during an exposure period the stored charge such that a voltage associated with the stored charge is decreased in response to received light, and to provide a first output signal that is associated with a remaining stored charge of the first pixel; a detector that is configured to determine whether an oversaturation condition exists at a detection time that is after the initialization period and that is before the end of the integration period by monitoring a decrease in the first output signal that is associated with the remaining stored charge of the first pixel; and a first sampler that is configured to sample after the exposure period the first output signal to produce a first pixel sampled quantity that is associated with a first pixel within an image, sample in response to the detector determining that an oversaturation condition exists a second reference voltage after the detection time to produce a first reference sampled quantity, sample in response to the detector determining that an oversaturation condition does not exist the first output signal to produce the first reference sampled quantity, and to subtract the first pixel sampled quantity from the reference sampled quantity to produce a first pixel value for the image.