Voltage Booster Circuit for Small-Pixel Image Sensor Charge Gain
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Solution Overview
Problem
The miniaturization of imaging devices, such as CCD-type imaging devices, is limited due to the requirement of multiple power source voltages, and the reduction in pixel size leads to a decrease in the amount of electric charge stored, resulting in a deteriorated signal-to-noise ratio and image quality.
Innovation Solution
A voltage generation circuit that includes a booster circuit with a capacitance element and a transistor, a control buffer circuit, and a driving buffer circuit, capable of generating a higher positive voltage or a lower negative voltage than the power source voltage, allowing for improved image quality without increasing pixel size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pixel size is reduced to enable miniaturization of the imaging device, then the device size is reduced, but the amount of electric charge stored in the pixel decreases, resulting in deteriorated signal-to-noise ratio and image quality
Solution Approach 1:
The patent applies parameter changes by introducing high voltage or negative voltage to alter the electrical characteristics of the pixel. This enables the pixel to store sufficient electric charge even when the pixel size is reduced, thereby maintaining signal-to-noise ratio and image quality while achieving device miniaturization.
2Reliability
If multiple power source voltages are used to maintain image quality in CCD-type imaging devices, then image quality is preserved, but the device complexity increases and miniaturization is limited
Solution Approach 1:
The patent applies universality by using a single power source voltage that can generate both high voltage and negative voltage through the voltage generation circuit. This multi-functional approach eliminates the need for multiple separate power source voltage inputs, reducing device complexity while maintaining image quality.
3Quantity of substance
If higher voltage or negative voltage is applied to increase the amount of electric charge stored in the pixel, then the signal-to-noise ratio is improved, but the device complexity increases due to additional voltage generation requirements
Solution Approach 1:
The patent applies merging by integrating the high voltage generation circuit and negative voltage generation circuit into a unified voltage generation system. This combined circuit architecture reduces overall device complexity while providing the necessary high voltage and negative voltage to increase electric charge storage in the pixel and improve signal-to-noise ratio.
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 proposed voltage generation circuit enables the generation of necessary voltages for imaging devices, enhancing image quality by increasing the amount of electric charge stored in pixels, while also facilitating the miniaturization of imaging devices.
Implementation Method 1
a booster circuit including a capacitance element C12 and a transistor SW12
Data Source
AI summary
A voltage generation circuit includes a booster circuit, a control buffer circuit, and a driving buffer circuit. The booster circuit includes a capacitance element and a transistor. The booster circuit generates a higher first voltage than the power source voltage, and the control buffer circuit controls the transistor by using a third voltage that is lower than the first voltage and is higher than a ground voltage. Alternatively, the booster circuit generates a lower second voltage than the ground voltage, and the control buffer circuit controls the transistor by using a fourth voltage that is higher than the second voltage and is lower than or equal to the ground voltage.