Image Sensor ADC Comparator Timing for Noise Reduction
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Solution Overview
Problem
Existing image sensors face challenges in reducing noise while maintaining high-speed Analog to Digital (AD) conversion, as multiple AD conversions are required to achieve noise reduction, which increases processing time.
Innovation Solution
An image sensor design that includes a pixel with a photoelectric conversion element, a reference signal output unit, and an Analog Digital Converter (ADC) with a comparator and counter, utilizing differential amplifiers and output amplifiers to amplify comparison results at different timings, allowing for efficient noise reduction without significant increases in processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple AD conversions are performed to reduce noise in pixel values, then noise reduction is achieved, but processing time increases
Solution Approach 1:
The patent divides the comparison result signal processing into multiple segments by using a plurality of output amplifiers that output at different timings. Each amplifier processes a portion of the comparison results, allowing parallel processing of multiple AD conversion results without requiring sequential operation, thus reducing noise while maintaining high-speed conversion.
Solution Approach 2:
The patent performs preliminary amplification of comparison result signals through multiple output amplifiers before final processing. By preparing multiple amplified signals at different timings in advance, the system can quickly access ready-to-use signals for noise reduction calculations without waiting for sequential conversion completion.
2Measurement precision
If multiple AD conversions are performed sequentially, then noise reduction is achieved, but conversion speed decreases
Solution Approach 1:
The patent maintains continuous useful action by having multiple output amplifiers operate simultaneously at different timings. While one amplifier is processing, others are preparing or outputting signals, ensuring continuous signal availability for noise reduction without interruption to the conversion process, thereby maintaining high conversion speed.
Solution Approach 2:
The patent employs periodic action through output amplifiers that operate at different timed intervals. Each amplifier outputs amplified comparison result signals at specific periodic timings, creating a continuous stream of processed signals that enables noise reduction while maintaining rapid conversion throughput.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables effective noise reduction in image sensors while maintaining high-speed AD conversion, reducing processing time and improving image quality.
Implementation Method 1
a pixel that has a photoelectric conversion element for performing photoelectric conversion and outputs an electrical signal
Data Source
AI summary
The present technology relates to an image sensor, an electronic apparatus, a comparator, and a drive method which enable achievement of a noise reduction while maintaining high speed of AD conversion. An ADC for performing AD conversion for an electrical signal output from a pixel includes a comparator that compares the electrical signal and a reference signal, a level of which is changed and a counter that counts time necessary for a change of the reference signal to a coincidence of the electrical signal and the reference signal on the basis of output signals from the comparator. The comparator includes a differential amplifier that outputs a comparison result signal indicating a comparison result obtained by comparing the electrical signal and the reference signal and a plurality of output amplifiers that outputs signals obtained by amplifying the comparison result signal output from the differential amplifier as the output signals at different timings. The present technology can be applied to, for example, an ADC that performs AD conversion for an electrical signal output from a pixel.