Image Sensor Voltage Supply Circuit for Illumination Adaptation
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Solution Overview
Problem
CMOS image sensors face operational abnormalities due to excessive electron generation under high illumination, leading to inefficient voltage supply management.
Innovation Solution
An image sensor with a voltage supply circuit that includes a comparator, voltage generator, and switch to dynamically adjust voltage supply to pixels based on illumination changes, switching between a first and second voltage to prevent overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed voltage is supplied to pixels, then the circuit design is simple, but the pixels cannot adapt to high illumination conditions leading to operational abnormalities
Solution Approach 1:
The voltage supply circuit dynamically adjusts the voltage level supplied to pixels based on illumination conditions. A voltage supply controller monitors the illumination level and switches between a first voltage (for low illumination) and a second voltage (for high illumination), making the system adaptive rather than static.
Solution Approach 2:
The voltage supply circuit incorporates feedback mechanisms where the voltage supply controller detects the current voltage level and illumination conditions, then adjusts the voltage output accordingly. This closed-loop control enables the system to respond to changing illumination conditions and maintain optimal pixel operation.
2Measurement precision
If voltage is increased to improve signal quality, then detection precision improves, but pixels generate excessive electrons under high illumination causing abnormal operation
Solution Approach 1:
The system changes the voltage parameter based on illumination conditions. Under low illumination, a first voltage level is applied to optimize signal detection precision. Under high illumination, the voltage is switched to a second level to prevent excessive electron generation, thus adapting the electrical parameter to environmental conditions.
Solution Approach 2:
The voltage supply controller proactively switches to a lower voltage level before excessive electron generation occurs by detecting high illumination conditions in advance. This preliminary adjustment prevents the harmful effect of electron saturation before it degrades image quality.
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
Effectively manages voltage supply to pixels, preventing operational abnormalities and ensuring stable performance across varying illumination conditions.
Implementation Method 1
Each of the plurality of pixels includes a photo-electric conversion element which converts an optical signal into an electrical signal
Implementation Method 2
a comparator configured to compare a reference signal with the signal from the first voltage supply line and generate a comparison signal
Data Source
AI summary
An image sensor includes a pixel array including a plurality of pixels, a row driver configured to control an operation of each of the plurality of pixels, a voltage supply line connected to a reset transistor included in each of the plurality of pixels, and a voltage supply circuit which detects a signal from the voltage supply line and supplies one of a first voltage and a second voltage to the voltage supply line based on the signal from the voltage supply line.