Charge-Balanced ADC Control for High-Current Image Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microelectronic imaging devices face limitations in achieving both good linearity and high conversion dynamics, particularly when dealing with high detection currents, which can lead to blocking of scanning processes and insufficient resolution.
Innovation Solution
A microelectronic device with a detector and an analog/digital converter that includes a comparator, charge injector, and control means to modulate the charge injection based on the intensity of the detection current, allowing for variable charge injection quantities and frequencies to adapt to changing light intensities, thereby preventing blocking and improving dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed quantity charge injection is used, then device complexity is reduced, but conversion dynamics and linearity deteriorate under high detection currents
Solution Approach 1:
The charge injection quantity is made variable through a control means that adjusts the injected charge amount based on the detection current intensity. This dynamic adjustment allows the system to maintain optimal performance across different light intensity conditions, resolving the contradiction between fixed complexity and variable precision requirements.
Solution Approach 2:
The system changes the parameter of charge injection quantity from fixed to variable by introducing control means that modulates the injected charge amount. This parameter change enables adaptation to different detection current levels, improving both linearity and conversion dynamics without excessive complexity increase.
2Productivity
If high detection current is processed, then conversion dynamics improve, but blocking of scanning process occurs
Solution Approach 1:
The control means dynamically adjusts the charge injection quantity based on detection current intensity. When detection current is high, the system increases charge injection to maintain scanning continuity and prevent blocking, thereby maintaining both high conversion dynamics and reliable operation.
Solution Approach 2:
The control means uses feedback from the detection current to modulate the charge injection quantity. This feedback mechanism ensures that the scanning process continues smoothly under high detection current conditions by adjusting injection parameters in real-time, preventing blocking while maintaining productivity.
3Adaptability or versatility
If variable charge injection quantity is implemented, then conversion dynamics improve, but device complexity increases
Solution Approach 1:
The system implements variable charge injection by changing the parameter of injected charge amount through control means. This approach provides improved adaptability and conversion dynamics while managing complexity through parameter-based control rather than structural complexity.
Solution Approach 2:
The control means selectively activates different numbers of charge injectors based on detection current intensity, effectively discarding unnecessary injectors during low current conditions and recovering full capability during high current conditions. This approach manages complexity by using only the required number of injectors at any given time.
4Measurement precision
If multiple charge injectors are used, then measurement precision improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The charge injection function is segmented into multiple independent charge injectors, each capable of being selectively activated. This segmentation allows the system to achieve high measurement precision through coordinated operation of multiple injectors while managing manufacturing complexity by using identical, modular injector units.
Solution Approach 2:
Multiple charge injectors are designed with identical structure and function, allowing them to be manufactured using the same process. This universality improves measurement precision through parallel operation while simplifying manufacturing by repeating a proven design rather than creating complex unique structures.
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 enables improved conversion dynamics and prevents blocking during high detection currents, allowing for more extensive and accurate light intensity range capture without prior prediction, maintaining good linearity and precision in image sensing.
Implementation Method 1
a detector, provided for example with at least one photodiode or at least one phototransistor, provided for converting the energy of photons incident on the pixel into electron-hole pairs
Implementation Method 2
a capacity of integration, whose role is to store these charges
Implementation Method 3
injector means of charges capable of modifying the analog signal by at least one injection of a given quantity of charges Qc into said capacitor
Data Source
AI summary
The sensor has an analog/digital conversion unit with a comparator (130) receiving an analog signal (Vint) of an integration capacitor (110) and delivering an output signal (Scomp) adopting a stable state or another state. A charge injection unit (190) modifies the analog signal by injection of a given charge quantity in the capacitor consecutive to a state change from the stable state to the other state, at an output of the comparator. A charge injection unit control module (250) modifies the quantity based on an intensity of a current (Idet) delivered by a detector (50) e.g. photodiode. An independent claim is also included for a method for controlling a microelectronic device.