Floating Diffusion Voltage Boosting for Low-Lag Image Sensing
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Solution Overview
Problem
Current image sensing devices face challenges in efficiently transmitting photocharge from photodiodes to floating diffusion nodes, leading to charge loss and image lag due to limitations in voltage control and signal processing.
Innovation Solution
The proposed image sensing device includes a floating diffusion node, initialization, boosting, transmission, and selection blocks, with control signals managing voltage levels to enhance photocharge transmission and pixel signal generation, improving transmission capability and reducing charge loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage control is simplified in image sensing devices, then device complexity is reduced, but photocharge transmission capability deteriorates leading to charge loss and image lag
Solution Approach 1:
The patent applies dynamic voltage control by sequentially changing the voltage level of the floating diffusion node during different operation periods. During the reference period, a first voltage level is applied, and during the transmission period, a second voltage level is applied. This dynamic voltage adjustment optimizes photocharge transmission capability while maintaining manageable device complexity through systematic control signal management.
Solution Approach 2:
The patent implements periodic voltage control by dividing operation into distinct periods (reference period and transmission period) with different voltage levels. The control block generates periodic control signals that switch the floating diffusion node voltage between first and second levels at appropriate times, ensuring optimal photocharge transmission during critical periods while maintaining overall system simplicity.
2Reliability
If voltage levels are increased to improve photocharge transmission, then transmission capability is improved, but energy consumption increases
Solution Approach 1:
The patent reduces energy consumption by applying high voltage levels only during specific transmission periods when photocharge transfer is needed, rather than maintaining high voltage continuously. The control block switches between first and second voltage levels periodically, ensuring high transmission capability only when required, thereby optimizing the balance between transmission performance and energy efficiency.
Solution Approach 2:
The patent dynamically adjusts voltage levels based on operational requirements, using a second voltage level (higher than first) only during transmission periods when improved photocharge transmission is needed. During other periods, the system operates at the lower first voltage level, reducing overall energy consumption while maintaining transmission capability when required.
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 improved transmission capability reduces charge loss and image lag, enhancing the overall performance of the image sensing device by effectively managing voltage levels and signal processing.
Implementation Method 1
a photodiode suitable for generating a photocharge based on incident light
Data Source
AI summary
An image sensing device includes: a floating diffusion node; an initialization block suitable for initializing the floating diffusion node with a first voltage, based on an initialization control signal; a boosting block suitable for boosting the floating diffusion node with a second voltage, based on a boost control signal; a photodiode suitable for generating a photocharge based on incident light; a transmission block suitable for transmitting the photocharge to the floating diffusion node based on a transmission control signal; and a selection block suitable for generating a pixel signal corresponding to a voltage loaded on the floating diffusion node based on a selection control signal.