Imaging pixels with improved analog-to-digital circuitry

摘要

Imagers may include analog-to-digital converter circuitry that produces a digital output code from an analog input voltage. The analog-to-digital converter circuitry may include a series of capacitors including a first set of binary-mapped capacitors. The analog-to-digital converter circuitry may include a second set of one or more capacitors that have capacitances that are less than binary-mapped capacitance values. The digital output code may include bits having respective bit positions within the digital output code. During successive-approximation operations performed by the analog-to-digital converter circuitry, each bit of the digital output code may be produced using a corresponding capacitor. Digital processing circuitry such as an image processor may produce a digital value from the digital output code by multiplying the bits of the digital output code with respective weights determined based on the capacitance of the corresponding capacitors.

主权项

1. Imaging circuitry, comprising:
an analog-to-digital converter circuit that produces a digital output code from an analog input voltage and comprises a plurality of capacitors and an additional capacitor having a given capacitance, wherein the plurality of capacitors comprises a first capacitor and a set of capacitors, wherein the first capacitor has a first capacitance, wherein each of the capacitors in the set of capacitors has a capacitance that is equal to the first capacitance multiplied by some power of 2, and wherein the given capacitance is greater than the capacitances of each of the capacitors in the plurality of capacitors and less than twice the capacitance of a capacitor in the plurality of capacitors that has the largest capacitance; and digital processing circuitry that generates a digital output value from the digital output code from the analog-to-digital converter circuit.