Solid State Imaging Device Decimation Output Circuit
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Solution Overview
Problem
In solid state imaging devices, performing decimation outputting based on addition and averaging in pixels connected to other vertical signal lines increases circuit scale, operation speed, and power consumption, especially when using color filter arrays like those with white filters.
Innovation Solution
A solid state imaging device with a pixel array unit and A/D conversion units that include a switching unit to switch or convert analog signals from one signal line to digital using either the corresponding A/D conversion unit or an adjacent unit, allowing for decimation outputting without increasing circuit scale or power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If decimation outputting is performed using addition and averaging in pixels connected to other vertical signal lines, then imaging functionality is improved, but circuit scale increases
Solution Approach 1:
The A/D conversion unit is designed to perform multiple functions: it converts analog signals from its corresponding signal line and also processes analog signals from other vertical signal lines through the switching unit. This multi-functionality allows decimation outputting without requiring separate dedicated circuits for each function, thereby avoiding circuit scale increase while maintaining enhanced imaging functionality
Solution Approach 2:
The switching unit acts as an intermediary that routes analog signals from multiple vertical signal lines to the appropriate A/D conversion unit. This mediator component enables flexible signal routing and sharing of A/D conversion resources without requiring direct complex interconnections between all signal lines and all A/D units, thus resolving the circuit complexity issue
2Adaptability or versatility
If decimation outputting is performed using addition and averaging in pixels connected to other vertical signal lines, then imaging functionality is improved, but power consumption increases
Solution Approach 1:
The A/D conversion unit serves multiple signal lines through the switching unit, meaning that one A/D unit can handle conversions for multiple vertical signal lines at different time periods. This reduces the total number of A/D conversion operations needed across the system, thereby reducing overall power consumption while maintaining the ability to perform decimation outputting for enhanced imaging functionality
Solution Approach 2:
The switching unit enables time-multiplexed operation where analog signals from different vertical signal lines are sequentially routed to A/D conversion units in periodic cycles. This periodic sharing of A/D conversion resources reduces the simultaneous power demand compared to having dedicated A/D units operating in parallel for all signal lines, thus lowering overall power consumption while maintaining imaging functionality
3Adaptability or versatility
If decimation outputting is performed using addition and averaging in pixels connected to other vertical signal lines, then imaging functionality is improved, but operation speed decreases
Solution Approach 1:
The switching unit is designed to pre-route and prepare analog signals from multiple vertical signal lines for A/D conversion in an organized sequence. By establishing the signal routing paths and conversion scheduling in advance through the switching control logic, the system minimizes runtime decision-making delays and optimizes the operation speed of the decimation outputting process while maintaining enhanced imaging functionality
Data Source
AI summary
A solid state imaging device includes: a pixel array unit that has a plurality of pixels 2-dimensionally arranged in a matrix and a plurality of signal lines arranged along a column direction; A/D conversion units that are provided corresponding to the respective signal lines and convert an analog signal output from a pixel through the signal line into a digital signal; and a switching unit that switches or converts the analog signal output through each signal line into a digital signal using any of an A/D conversion unit provided corresponding to the signal line through which the analog signal is transmitted, and an A/D conversion unit provided corresponding to a signal line other than the signal line through which the analog signal is transmitted.