Ramp Signal Generator Using Segmented Currents for Better Linearity
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Solution Overview
Problem
Existing image sensor technologies face challenges in generating high-quality ramping signals due to issues like gain non-linearity and large glitch power, which affect the quality of output, and there is a need for a signal generator with low power consumption and a small physical area.
Innovation Solution
A system and method that utilize a series of storage circuits and current generating circuits to propagate an enable signal, generating a ramping signal by converting current signals into voltage signals through a load block, with the option of incorporating an offset segment to enhance signal resolution and reduce non-linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ramp signal generators are used, then the image sensor can operate, but the ramping signal exhibits poor linearity causing gain non-linearity in column read circuits
Solution Approach 1:
The ramp signal generator is divided into multiple independent current generating circuits (first current generating circuit, second current generating circuit, etc.), each contributing a portion of the total ramp current. This segmentation allows precise control over the ramp signal's linearity by independently optimizing each segment's contribution, while keeping individual circuit blocks simple and modular.
Solution Approach 2:
Multiple current generating circuits are merged together to form the complete ramp signal generator. The first current generating circuit generates a primary ramp current, the second current generating circuit generates a correction current, and their combined output through the load block produces a high-linearity ramping signal. This merging approach achieves superior linearity without requiring each individual circuit to be overly complex.
2Object-affected harmful factors
If conventional ramp signal generators are used, then the image sensor can operate, but large glitch power is generated causing lost-bit effects
Solution Approach 1:
The harmful glitch effects are extracted and addressed by a dedicated second current generating circuit that generates a correction current specifically designed to cancel out glitches from the first current generating circuit. This separation allows the primary ramp generation and glitch correction to be handled independently, effectively reducing glitch power while maintaining signal integrity.
Solution Approach 2:
The glitch effects, which are harmful in themselves, are converted into a beneficial correction mechanism. The second current generating circuit uses the glitch information to generate a compensating current that actively cancels the harmful effects, transforming the glitch problem into an opportunity for enhanced signal quality through adaptive correction.
3Use of energy by moving object
If a ramp signal generator with low power consumption and small physical area is designed, then power efficiency is improved, but achieving high signal quality becomes more difficult
Solution Approach 1:
The ramp signal generator is segmented into multiple independent current generating circuits, each operating at lower power levels. This segmentation allows the system to achieve high signal quality through the combined output of several simple, low-power circuits rather than relying on a single complex high-power circuit, thus maintaining signal integrity while reducing overall power consumption.
Solution Approach 2:
Each current generating circuit is designed to be multi-functional, serving both as a ramp current source and as a glitch correction mechanism. The first current generating circuit provides the primary ramp signal, while the second current generating circuit simultaneously provides glitch correction. This multi-functionality reduces the need for separate dedicated circuits, minimizing physical area and power consumption while maintaining high signal 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
The solution effectively generates high-quality ramping signals with improved linearity and reduced glitch power, achieving low power consumption and a compact design, thereby enhancing the performance and flexibility of image sensors.
Implementation Method 1
a load block coupled to the plurality of first current generating circuits and the one or more second current generating circuits. The load block converts the first and second current signal to a voltage signal to generate the ramping signal
Data Source
AI summary
A system is provided for generating a ramping signal. The system includes a plurality of storage circuits each including an input and an output. The output of a previous storage circuit is connected to the input of a next storage circuit. The storage circuits are configured to propagate a first enable signal based on a first control signal. The system also includes a plurality of first current generating circuits. Each first current generating circuit is coupled to the output of a corresponding storage circuit to receive the propagated first enable signal. The first current generating circuits are configured to generate a first current signal based on the propagated first enable signal.