Multi-Mode CMOS Image Sensor Circuit for Imaging and Memory
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Solution Overview
Problem
Conventional CMOS image sensors are limited in their functionality, as they primarily perform image sensing without the capability to store or process multi-value data, restricting their operational modes and efficiency.
Innovation Solution
The integration of a multi-mode circuit within the CMOS image sensor that enables both imaging and memory functions, allowing for the collection, storage, and reading of multi-value states, utilizing a photo-detector, transfer gate, write circuit, and read circuit to manage electrons and voltage levels, and including a semiconductor device with element arrays, write and read enable arrays to switch between image and memory modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional CMOS image sensors are used with dedicated additional circuitry for voltage conversion and buffering, then the sensor can perform image sensing functions, but it lacks the capability to store or process multi-value data, restricting operational modes
Solution Approach 1:
The pixel circuit is designed to perform multiple functions by reconfiguring existing components. The circuit can operate as an imaging pixel during integration periods (converting photo-generated charge to voltage) and as a memory cell during memory periods (storing multi-value data states), eliminating the need for separate dedicated circuitry for each function.
Solution Approach 2:
The circuit employs dynamic reconfiguration through control signals that switch the operational mode between imaging and memory functions. Transistors are dynamically controlled to connect different circuit paths, allowing the same hardware to adapt its behavior based on the current operational requirement without physical reconfiguration.
2Adaptability or versatility
If additional dedicated circuitry is added to enable memory functions, then multi-value data storage capability is achieved, but device complexity increases
Solution Approach 1:
The imaging and memory functions are merged into a single integrated circuit structure. The pixel circuit shares common components such as transistors, capacitors, and interconnect structures between its imaging mode and memory mode operations, consolidating functionality rather than adding separate dedicated circuits for each function.
Solution Approach 2:
The same circuit components serve dual purposes: during imaging mode, the circuit captures and converts light signals; during memory mode, the same circuit stores and retains multi-value data states. This universal design allows one circuit structure to replace what would traditionally require separate imaging and memory circuits.
3Productivity
If the sensor operates in multiple modes with multi-value data processing, then operational efficiency is improved, but the difficulty of detecting and measuring states increases
Solution Approach 1:
The circuit utilizes multi-value voltage states (e.g., multiple distinct voltage levels representing different data values) that can be detected through standard voltage thresholding techniques. By encoding data in distinct voltage levels rather than requiring complex quantum or optical states, the system maintains compatibility with conventional CMOS readout circuits while enabling multi-value storage.
Solution Approach 2:
The patent replaces complex measurement mechanisms with standard electronic voltage detection. Instead of requiring specialized sensors or complex measurement apparatus to detect multi-value states, the system uses conventional voltage thresholding and comparison circuits that are already present in CMOS technology, simplifying the detection process.
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
Enables the CMOS image sensor to operate in both image sensing and memory modes, enhancing its functionality by allowing the storage and processing of multi-value data, thereby improving its operational efficiency and versatility.
Implementation Method 1
a photo-detector configured for collecting electrons generated by a radiation impinging on the photo-detector
Data Source
AI summary
Methods, devices, and systems for image sensors are disclosed that include a multi-mode circuit that can be configured for operating as an imaging pixel and a memory. The multi-mode circuit includes a photo-detector for collecting electrons generated by radiation impinging on the photo-detector. A transfer gate is configured for transferring the collected electrons from the photo-detector to a floating diffusion node when the transfer gate is enabled. A write circuit receives and stores a multi-value voltage on the floating diffusion node and a read circuit is configured for reading a state of the floating diffusion node. The state of the floating diffusion node corresponds to the amount of transferred electrons in an image mode or the multi-value voltage in a memory mode. The semiconductor image sensor may be included in as part of an imaging system that includes a memory for storing a digital representation of an image.