Successive approximation analog-to-digital converter, imaging device, imaging system, and moving body
AssigneeCanon Kabushiki Kaisha
InventorsHirofumi Totsuka, Daisuke Yoshida
Life of this patent
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Abstract
A successive approximation analog-to-digital converter causes a comparator to compare an analog signal and a comparison signal that a first digital-to-analog converter converts into a voltage with an offset applied to the comparison signal by an offsetting unit. The successive approximation analog-to-digital converter can successfully carry out the second AD conversion and successive AD conversions of a signal.
Claims17
A successive approximation analog-to-digital converter that converts an analog signal into an N-bit (N is an integer of 2 or more) digital signal, the successive approximation analog-to-digital converter comprising:
- a comparator that receives as inputs, the analog signal and a comparison signal;
- a first digital-to-analog converter that converts the comparison signal into a voltage corresponding to each bit of the N bits;
- a second digital-to-analog converter that includes an offsetting unit that applies an offset corresponding to lower n bits of the N bit to the comparison signal;
- and
- a controller that causes the comparator to perform a plurality of comparisons between the analog signal and the comparison signal that the first digital-to-analog converter converts into the voltage with the offset applied to the comparison signal,
- wherein an amount of the offset applied to the comparison signal by the offsetting unit is a same amount in each of the plurality of comparisons.
An imaging device comprising:
- pixels each of which includes photoelectric converters;
- and
- a successive approximation analog-to-digital converter,
- wherein each of the pixels outputs a first signal based on electric charges of some of the photoelectric converters and a second signal based on electric charges of all of the photoelectric converters,
- wherein the successive approximation analog-to-digital converter converts the first signal into a digital signal at least two times and converts the second signal into a digital signal at least two times, and
- wherein a bit number when the first signal is converted at a second time is lower than a bit number when the second signal is converted at a second time.
Dependencies are inferred from the claim text.