Pixel Array Current Balancing for Stable Photoelectric Conversion
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Solution Overview
Problem
The accuracy of output signals from solid-state image capturing apparatuses deteriorates due to variations in power supply voltage.
Innovation Solution
A photoelectric conversion apparatus with a control unit that adjusts the current flowing through different sources to stabilize the total current flow, thereby minimizing variations in power supply voltage and improving signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the current flowing through pixel columns is adjusted to improve signal accuracy, then measurement precision improves, but device complexity increases due to the need for multiple current sources and control mechanisms
Solution Approach 1:
The pixel array is divided into multiple pixel groups (first pixel group, second pixel group, third pixel group) connected to different current sources (first current source, second current source, third current source). This segmentation allows independent current control for different regions, enabling precise signal measurement while managing complexity through modular organization.
Solution Approach 2:
The patent employs dynamic current control where the control unit adjusts the current flowing through different current sources based on reading requirements. The current values can be changed over time to optimize signal accuracy for different pixel groups, implementing adaptive measurement precision without permanently increasing device complexity.
2Measurement precision
If multiple current sources are used to improve signal accuracy, then measurement precision improves, but loss of energy increases due to higher total current consumption
Solution Approach 1:
Different current sources provide different current values to different pixel groups based on their specific measurement requirements. The control unit optimizes current distribution locally, allocating higher current only where needed for accurate measurement, thereby improving signal accuracy while minimizing overall energy consumption across the entire pixel array.
Data Source
AI summary
An apparatus includes a plurality of pixels arranged in an array, a first group of pixels that are arranged in a first direction among the plurality of pixels, a first line to which the first group is connected, a second group of pixels that are arranged in the first direction among the plurality of pixels, and a second line to which the second group is connected. The first line is connected to a first source. The second line is connected to a second source. The apparatus further includes a control unit configured to: (1) perform control to increase a current flowing through the second source while performing control to decrease a current flowing through the first source, or (2) suppress a variation of total amount of flowing current by changing the current flowing through the second source in response to a change in the current flowing through the first source.