Pixel Drive Charge Pump Circuit for Compact Image Sensor Voltage Control
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Solution Overview
Problem
Existing image sensors face challenges in efficiently providing voltage to pixels, particularly in compact designs where space for voltage regulators is limited, and require innovative solutions to manage voltages outside the standard supply levels for control lines.
Innovation Solution
The image sensor incorporates a voltage regulating circuit with a charge pump and a driver circuit featuring multiple switches and connection lines that act as buffer capacitors, allowing for selective and efficient distribution of output voltage and terminal voltage to pixels, enabling operation at high frame rates and in varying light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a voltage regulating circuit is integrated into the image sensor, then voltage control capability is improved, but the area occupied by the circuit increases
Solution Approach 1:
The patent combines the voltage regulating circuit with the pixel array structure, integrating the charge pump and control logic within the same semiconductor substrate as the pixels. This merging approach allows voltage regulation functionality to be added without requiring separate discrete components, thereby improving voltage control capability while minimizing additional area occupation.
Solution Approach 2:
The voltage regulating circuit is designed to serve multiple functions: it provides variable voltage control to different pixel rows, supports different operating modes (readout, reset, transfer), and can be configured through control signals to adapt to various imaging conditions. This multi-functionality reduces the need for separate dedicated circuits for each function, optimizing area usage.
2Adaptability or versatility
If multiple switches and connection lines are used for voltage distribution, then voltage selection flexibility is improved, but device complexity increases
Solution Approach 1:
The driver circuit is segmented into multiple independently controllable switch units, each associated with specific connection lines. This segmentation allows selective activation of voltage distribution paths based on operational requirements, improving voltage selection flexibility while keeping each individual switch unit simple and manageable.
Solution Approach 2:
The circuit employs dynamically controllable switches that can change their conductive state based on control signals. This dynamic behavior allows the same physical infrastructure of switches and connection lines to serve different voltage distribution configurations at different times, enhancing flexibility without requiring multiple static circuit paths.
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
This solution enables efficient voltage management, reducing peak currents and area requirements, allowing for high-performance image capture in compact formats, such as micro-camera modules and endoscope applications, while maintaining image quality and reducing costs.
Implementation Method 1
The voltage regulating circuit comprises a charge pump. The charge pump generates the output voltage.
Implementation Method 2
The first number N of connection lines are at least temporarily configured as buffer capacitor of the voltage regulating circuit.
Data Source
AI summary
An image sensor comprises an array comprising rows and columns of pixels, a first number N of connection lines connected to a first number N of pixels of the array, a voltage regulating circuit having an output, a first terminal, and a driver circuit. The driver circuit has a first number N of switches coupled to the first number N of connection lines and to the output of the voltage regulating circuit, and a first number N of further switches coupled to the first number N of connection lines and to the first terminal. The first number N is at least two.