Image sensors with low noise readout
AssigneeSemiconductor Components Industries, LLC
InventorShankar Ramakrishnan
Life of this patent
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Abstract
Imaging circuitry is provided that includes a column of image pixels coupled to a pixel output line, a first data converter circuit having an input coupled to the pixel output line and configured to output a first set of bits, an integrator having an input coupled to the first data converter, and a second data converter circuit having an input coupled to the integrator and configured to output a second set of bits. The first data converter circuit can be a successive-approximation-register analog-to-digital converter. The integrator can include an amplifier for charging up an integration capacitor. The second set of bits can be scaled based on a calibrated value prior to being combined with the first set of bits.
Claims20
Imaging circuitry comprising:
- a plurality of image pixels coupled to a pixel output line;
- a first data converter circuit having an input coupled to the pixel output line and configured to output a first set of bits;
- an integrator having an input coupled to the first data converter circuit;
- and
- a second data converter circuit having an input coupled to the integrator and configured to output a second set of bits.
A method of operating imaging circuitry comprising:
- with a first data converter, sampling a reset voltage;
- with an integrator having an input coupled to the first data converter, generating a first integrated value during a first integration phase;
- with a second data converter different than the first data converter, performing first conversion operations based on the first integrated value;
- with the first data converter, sampling an image signal voltage and then performing second conversion operations to produce a coarse code;
- and
- with the integrator, generating a second integrated value during a second integration phase.
A method of operating imaging circuitry comprising:
- during a vertical blanking period, performing calibration to obtain a calibrated value;
- and
- during readout:
- using a first data converter to output a coarse value;
- using a second data converter to output a fine value;
- and
- computing a final readout value based on the coarse value, the fine value, and the calibrated value.
Dependencies are inferred from the claim text.