US Patent 7804438 Image sensors and dual ramp analog-to-digital converters and methods

Dual ramp analog-to-digital converters and methods allow for performing analog-to-digital conversion of an analog signal. Various dual ramp analog-to-digital converters and methods allow for applying the analog signal and a coarse ramp to a same input of a comparator, and applying a fine ramp to another input of the comparator. Some dual ramp analog-to-digital converters and methods allow for applying the analog signal, a coarse ramp, and a fine ramp to a same input of a comparator. Various dual ramp analog-to-digital converters and methods allow for applying the analog signal to an input of a first comparator, applying a coarse ramp to the input of the first comparator through a coarse ramp switch, applying the analog signal to an input of a second comparator, and applying a fine ramp to another input of the second comparator.