Abstract: In one example, a method comprises: exposing a first photodiode to incident light to generate first charge; exposing a second photodiode to the incident light to generate second charge; converting, by a first charge sensing unit, the first charge to a first voltage; converting, by a second charge sensing unit, the second charge to a second voltage; controlling an ADC to detect, based on the first voltage, that a quantity of the first charge reaches a saturation threshold, and to measure a saturation time when the quantity of the first charge reaches the saturation threshold; stopping the exposure of the first photodiode and the second photodiode to the incident light based on detecting that the quantity of the first charge reaches the saturation threshold; and controlling the ADC to measure, based on the second voltage, a quantity of the second charge generated by the second photodiode before the exposure ends.

Abstract: In one example, an apparatus comprises a pixel cell array and a controller formed within a semiconductor package. The pixel cell array is configured to: generate, at a first time and based on first programming signals received from the controller, a first image frame; transmit the first image frame to a host processor; and transmit the first image frame or a second image frame to the controller, the second image frame being generated at the first time and having a different sparsity of pixels from the first image frame. The controller is configured to receive second programming signals from a host processor, the second programming signals being determined by the host processor based on the first image frame; update the first programming signals based on the second programming signals; and control the pixel cell array to generate a subsequent image frame based on the updated first programming signals.

Abstract: In one example, a method comprises: enabling a photodiode to, in response to incident light, accumulate residual charge, and to transfer overflow charge to a first charge storage device and a second charge storage device when the photodiode saturates; disconnecting the second charge storage device from the first charge storage device; enabling the photodiode to transfer the residual charge to the first charge storage device to cause the charge sensing unit to output a first voltage; quantizing the first voltage to generate a first digital value to measure the residual charge; connecting the second charge storage device with the first charge storage device to cause the charge sensing unit to output a second voltage; quantizing the second voltage to generate a second digital value to measure the overflow charge; and generating a digital representation of the incident light intensity based on the first digital value and the second digital value.

Abstract: In one example, an apparatus comprises: a comparator; a sampling capacitor having a first plate and a second plate. The first plate is coupled with an output of a charge sensing unit that senses charge generated by a photodiode, whereas the second plate is coupled with an input of the comparator. The apparatus further includes a controller configured to: at a first time, set a first voltage across the sampling capacitor based on an output voltage of the charge sensing unit; reset the charge sensing unit to set the first plate at a second voltage and to set the second plate at a third voltage based on the first voltage and the second voltage; compare, using the comparator, the third voltage against one or more thresholds; and generate, based on the comparison result, a quantization result of the output voltage of the charge sensing unit at the first time.

Abstract: In one example, an apparatus comprises: a photodiode, a charge storage unit, and an analog-to-digital converter (ADC) circuit. In a first mode, the ADC circuit can compare a first voltage representing a quantity of the overflow charge stored at the charge storage unit against a first ramping voltage to generate a first decision; and obtain, based on the first decision output, a first digital value. In a second mode, the ADC circuit can compare a second voltage representing a quantity of residual charge stored in the photodiode against a second ramping voltage to generate a second decision, and obtain, based on the second decision, a second digital value. The ADC circuit can determine, based on one of the first decision output or the second decision output, whether the photodiode saturates, and output one of the first digital value or the second digital value to represent an intensity of incident light.

Abstract: Methods and systems for performing analog-to-digital conversion is provided. In one example, an analog-to-digital converter (ADC) circuit comprises a leakage compensation circuit and a quantizer. The leakage compensation circuit is configured to: receive an input signal, the input signal being susceptible to a drift due to a charge leakage; receive a reference signal; and generate a leakage-compensated signal pair to compensate for the charge leakage, wherein the leakage-compensated signal pair comprises one of: (a) a leakage-compensated version of the input signal and the reference signal, (b) the input signal and a leakage-compensated version of the reference signal, or (c) a leakage-compensated version of the input signal and a leakage-compensated version of the reference signal. The quantizer is configured to perform a leakage-compensated quantization of the input signal based on the leakage-compensated signal pair to generate a digital output representing the input signal.

Abstract: In one example, an apparatus includes an array of pixel cells and a peripheral circuit. Each pixel cell of the array of pixel cells includes: a memory to store pixel-level programming data and measurement data, and light measurement circuits configured to, based on the pixel-level programming data from the control memory, perform a light measurement operation to generate the measurement data, and to store the measurement data at the data memory. The peripheral circuit is configured to: receive a pixel array programming map including pixel-level programming data targeted at each pixel cell; extract the pixel-level programming data from the pixel array programming map; and transmit the pixel-level programming data to each pixel cell of the array of pixel cells for storage at the memory of the each pixel cell and to individually control the light measurement operation and a generation of the measurement data at the each pixel cell.

Abstract: In one example, an apparatus comprises: an image sensor comprising an array of pixel cells, each pixel cell including a photodiode and circuits to generate image data, the photodiodes formed in a first semiconductor substrate; and a controller formed in one or more second semiconductor substrates that include the circuits of the array of pixel cells, the first and second semiconductor substrates forming a stack and housed within a semiconductor package. The controller is configured to: determine whether first image data generated by the image sensor contain features of an object; based on whether the first image data contain the features of the object, generate programming signals for the image sensor; and control, based on the programming signals, the image sensor to generate second image data.

Abstract: Examples of an image sensor are disclosed. In one example, the image sensor comprises a pixel cell, a switchable optical filter, and a controller. The switchable optical filter is configured to select a optical frequency range and allow incident light of the selected optical frequency range to reach the pixel cell. The controller is configured to operate the switchable optical filter to enable the pixel cell to: receive, at different times, information related to incident light of different optical frequency ranges, and generate, at the different times, intensity measurements of the incident light of different optical frequency ranges.

Abstract: Methods and systems for quantizing a physical quantity, such as light, are provided. In one example, an apparatus comprises an analog-to-digital (A/D) converter configured to generate raw digital outputs based on performing at least one of: (1) a first quantization operation to quantize a physical stimulus within a first intensity range based on a first A/D conversion relationship, or (2) a second quantization operation to quantize the physical stimulus within a second intensity range based on a second A/D conversion relationship; and a raw output conversion circuit configured generate a refined digital output based on a raw digital output obtained from the A/D converter and at least one predetermined conversion parameter. The at least one conversion parameter compensates for a discontinuity between the first A/D conversion relationship and the second A/D conversion relationship.

Abstract: Examples of an image sensor are disclosed. In one example, the image sensor comprises a dual-mode pixel cell operable in a first mode and in a second mode at different times, the pixel cell including a photodiode to receive incident light. The image sensor further comprises one or more configurable voltage sources coupled with the photodiode. In the first mode, the one or more voltage sources are configured to bias the photodiode to generate a quantity of charges that reflects a quantity of photons of the incident light received by the photodiode within a first exposure period. In the second mode, the one or more voltage sources are configured to bias the photodiode to generate a signal corresponding to a time when the photodiode receives a first photon of the incident light within a second exposure period for a time-of-flight measurement.

Abstract: In one example, an apparatus comprises: a first photodiode to generate a first charge; a second photodiode to generate a second charge; a quantizer; a first memory bank and a second memory bank; and a controller configured to: control the quantizer to perform a first quantization operation and a second quantization operation of the first charge to generate, respectively, a first digital output and a second digital output, the first and second quantization operations being associated with different intensity ranges; store one of the first digital output or the second digital output in the first memory bank; control the quantizer to perform a third quantization operation of the second charge to generate a third digital output, the third quantization operation being associated with a different intensity range from at least one of the first or second quantization operations; and store the third digital output in the second memory bank.

Abstract: In one example, a method comprises: exposing a first photodiode to incident light to generate first charge; exposing a second photodiode to the incident light to generate second charge; converting, by a first charge sensing unit, the first charge to a first voltage; converting, by a second charge sensing unit, the second charge to a second voltage; controlling an ADC to detect, based on the first voltage, that a quantity of the first charge reaches a saturation threshold, and to measure a saturation time when the quantity of the first charge reaches the saturation threshold; stopping the exposure of the first photodiode and the second photodiode to the incident light based on detecting that the quantity of the first charge reaches the saturation threshold; and controlling the ADC to measure, based on the second voltage, a quantity of the second charge generated by the second photodiode before the exposure ends.

Abstract: In one example, a method comprises: enabling a photodiode to, in response to incident light, accumulate residual charge, and to transfer overflow charge to a first charge storage device and a second charge storage device when the photodiode saturates; disconnecting the second charge storage device from the first charge storage device; enabling the photodiode to transfer the residual charge to the first charge storage device to cause the charge sensing unit to output a first voltage; quantizing the first voltage to generate a first digital value to measure the residual charge; connecting the second charge storage device with the first charge storage device to cause the charge sensing unit to output a second voltage; quantizing the second voltage to generate a second digital value to measure the overflow charge; and generating a digital representation of the incident light intensity based on the first digital value and the second digital value.

Abstract: In one example, an apparatus comprises: a plurality of photodiodes, one or more charge sensing units, one or more analog-to-digital converters (ADCs), and a controller. The controller is configured to: enable the each photodiode to generate charge in response to a different component of the incident light; transfer the charge from the plurality of photodiodes to the one or more charge sensing units to convert to voltages; receive a selection of one or more quantization processes of a plurality of quantization processes corresponding to a plurality of intensity ranges; based on the selection, control the one or more ADCs to perform the selected one or more quantization processes to quantize the voltages from the one or more charge sensing units to digital values representing components of a pixel of different wavelength ranges; and generate a pixel value based on the digital values.

Abstract: In one example, an apparatus comprises: a comparator; a sampling capacitor having a first plate and a second plate. The first plate is coupled with an output of a charge sensing unit that senses charge generated by a photodiode, whereas the second plate is coupled with an input of the comparator. The apparatus further includes a controller configured to: at a first time, set a first voltage across the sampling capacitor based on an output voltage of the charge sensing unit; reset the charge sensing unit to set the first plate at a second voltage and to set the second plate at a third voltage based on the first voltage and the second voltage; compare, using the comparator, the third voltage against one or more thresholds; and generate, based on the comparison result, a quantization result of the output voltage of the charge sensing unit at the first time.

Abstract: In one example, an apparatus is provided. The apparatus comprises an image sensor configured to generate a first raw output to represent a first intensity of incident light based on a first relationship, and to generate a second raw output to represent a second intensity of incident light based on a second relationship. The apparatus further comprises a post processor configured to: generate a first post-processed output based on the first raw output and based on the first relationship such that the first post-processed output is linearly related to the first intensity based on a third relationship, and to generate a second post-processed output based on the second raw output and based on the second relationship such that the second post-processed output is linearly related to the second intensity based on the third relationship.

Abstract: Methods and systems for performing analog-to-digital conversion is provided. In one example, an analog-to-digital converter (ADC) circuit comprises a leakage compensation circuit and a quantizer. The leakage compensation circuit is configured to: receive an input signal, the input signal being susceptible to a drift due to a charge leakage; receive a reference signal; and generate a leakage-compensated signal pair to compensate for the charge leakage, wherein the leakage-compensated signal pair comprises one of: (a) a leakage-compensated version of the input signal and the reference signal, (b) the input signal and a leakage-compensated version of the reference signal, or (c) a leakage-compensated version of the input signal and a leakage-compensated version of the reference signal. The quantizer is configured to perform a leakage-compensated quantization of the input signal based on the leakage-compensated signal pair to generate a digital output representing the input signal.

Abstract: In one example, an apparatus comprises a photodiode, a charge storage unit, and a processing circuits configured to: transfer overflow charge from the photodiode to the charge storage unit to develop a first voltage; compare the first voltage against a first ramping threshold voltage to generate a first decision; generate, based on the first decision, a first digital value; transfer residual charge from the photodiode to the charge storage unit to develop a second voltage; compare the second voltage against a static threshold voltage to determine whether the photodiode saturates to generate a second decision; compare the second voltage against a second ramping threshold voltage to generate a third decision; generate, based on the third decision, a second digital value; and output, based on the second decision, one of the first digital value or the second digital value to represent an intensity of light received by the photodiode.

Abstract: In one example, a method comprises: receiving programming data; determining, based on the programming data, at least one of: an integration period in which a charge storage unit including a floating drain accumulates charge received from a photodiode, or a number of times of sampling the charge; enabling the photodiode to accumulate residual charge, and to transmit overflow charge to the charge storage unit after the photodiode saturates; controlling the charge storage unit to accumulate at least a part of the overflow charge received from the photodiode within the integration period; controlling a quantizer to sample the at least a part of the overflow charge or the residual charge for the number of times to obtain the number of samples; and controlling the quantizer to quantize the number of samples to generate the number of quantization results.