Column Sample-and-Hold Ground Layout for Accurate Photoelectric Conversion
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Solution Overview
Problem
The existing photoelectric conversion devices, such as those described in International Publication No. WO2019/069614, require further improvement in accuracy for signal processing, particularly in the handling and conversion of signals from pixels in a solid-state imaging element.
Innovation Solution
A photoelectric conversion device is designed with a pixel array and column circuits that include sample and hold units, delta-sigma analog-to-digital conversion circuits, and source follower circuits, where the ground lines for the sample and hold units are commonly connected to reduce noise and improve signal accuracy through correlated double sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate ground lines are used for first and second sample and hold units, then each unit can be independently optimized, but noise and potential fluctuations affect signal processing accuracy
Solution Approach 1:
The patent merges the ground lines of the first and second sample and hold units into a single common ground line. This combining of previously separate ground connections eliminates potential differences and ground loops between the two units, thereby reducing noise and potential fluctuations that affect signal processing accuracy.
Solution Approach 2:
By using a common ground line for both sample and hold units, the patent establishes an equipotential reference for both circuits. This ensures that both units operate at the same potential level, eliminating voltage differences that could introduce noise and improve the accuracy of differential signal processing.
2Measurement precision
If commonly connected ground lines are used for sample and hold units, then noise influence is reduced, but circuit design complexity increases
Solution Approach 1:
The patent simplifies the circuit design by merging separate ground lines into a single common ground line for the sample and hold units. This reduction in the number of ground connections decreases routing complexity while simultaneously improving signal accuracy by eliminating ground potential differences.
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
The proposed configuration enhances the accuracy of signal processing by reducing the influence of noise and potential fluctuations, leading to improved performance in converting analog signals to digital signals for imaging applications.
Implementation Method 1
a photoelectric conversion unit that generates charges in accordance with incident light
Data Source
AI summary
Provided is a photoelectric conversion device including: a pixel array including a plurality of pixels arranged to form a plurality of columns; and a column circuit arranged corresponding to each of the plurality of columns of the pixel array. The column circuit includes a sample and hold unit and a plurality of lines including a line configured to supply a potential to the sample and hold unit. The plurality of lines is commonly connected or separated in the photoelectric conversion device.