Solid-State Imaging Element Column Selection Circuit
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Solution Overview
Problem
The existing column ADC method for solid-state imaging devices requires multiple selection lines per row, which increases the number of lines in the pixel array, making miniaturization difficult and necessitating a reduction in the number of lines to facilitate pixel miniaturization.
Innovation Solution
A solid-state imaging device with a shared ADC for multiple columns, utilizing a power path opening/closing part and a signal path opening/closing part to individually control the paths between power supply lines and signal lines, allowing for reduced line count by enabling column selection with fewer selection lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple selection lines per row are disposed to transmit selection signals for selecting multiple columns, then column selection capability is improved, but the number of lines in the pixel array increases making miniaturization difficult
Solution Approach 1:
The patent merges the power supply path control and signal path control into a unified switching mechanism. The switching element simultaneously controls both the power supply line connection and the signal line connection based on a single selection signal, thereby reducing the number of selection lines required while maintaining the ability to select multiple columns for the shared ADC.
Solution Approach 2:
The switching element is designed to perform multiple functions: it acts as both a power supply switch and a signal path switch. This multi-functional design allows a single selection line to control both power delivery and signal routing to multiple columns, eliminating the need for separate selection lines for each function and reducing overall line count.
2Device complexity
If one ADC is shared by multiple columns to reduce ADC quantity, then device complexity is reduced, but the number of selection lines per row must increase
Solution Approach 1:
The patent implements dynamic control of the switching element that can selectively connect different columns to the shared ADC. The switching element responds to selection signals by dynamically establishing or breaking connections between power supply lines, signal lines, and the ADC, enabling flexible column selection without requiring dedicated ADCs for each column.
Solution Approach 2:
The switching element serves as an intermediary between the selection lines and the shared ADC. It mediates the connection by receiving selection signals and accordingly connecting or disconnecting specific column circuits from the shared ADC, thereby enabling one ADC to serve multiple columns without requiring individual dedicated control lines for each column-ADC pair.
3Productivity
If selection lines are increased to enable sharing of ADC among more columns, then ADC utilization is improved, but pixel miniaturization becomes more difficult
Solution Approach 1:
The patent segments the control function into a dedicated switching element that operates independently for each column group. This segmentation allows the switching element to control multiple columns through a single selection line by sequentially or selectively connecting them to the shared ADC, thereby improving ADC utilization without proportionally increasing the number of selection lines.
Solution Approach 2:
The patent introduces a time dimension to the column selection process by using sequential switching. Instead of requiring simultaneous independent control lines for each column, the switching element sequentially connects different columns to the shared ADC over time, effectively trading spatial complexity (number of lines) for temporal control (switching sequences), thereby enabling high ADC utilization with fewer lines and facilitating pixel miniaturization.
Data Source
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AI summary
In a solid-state imaging device in which a plurality of columns share one ADC, the number of lines in a pixel array is reduced. A plurality of circuits are each connected with one of a plurality of power supply lines disposed in a direction perpendicular to a predetermined direction. A signal processing part processes a pixel signal that is output via a signal line commonly connected with a predetermined number of adjacent pixel circuits in the predetermined direction from among a plurality of pixel circuits. A power path opening/closing part opens and closes a path between each of the plurality of power supply lines and a power supply. A common path opening/closing part opens and closes a path between each of the plurality of power supply lines and the signal line.