Configurable Non-Volatile CAM Cell for High-Density Neural Computing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Content Addressable Memory (CAM) systems, particularly those using SRAM, face limitations in scalability and cost due to large cell sizes, which restrict their application in high-density memory arrays, and they require significant power and time for memory data access, making them inefficient for large-scale computing tasks.
Innovation Solution
A configurable non-volatile CAM cell is developed using a pair of complementary non-volatile memory devices and an N-type or P-type MOSFET, allowing for the formation of NOR-type and NAND-type match line arrays, enabling efficient data storage and search operations without the need for continuous power, by configuring the devices to represent '1', '0', or 'don't care' bits using different voltage states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If SRAM-based CAM cells are used, then search operation speed is improved, but device area and manufacturing cost increase
Solution Approach 1:
The patent combines the CAM search function with non-volatile memory storage in a single integrated cell structure. The CAM cell includes a search unit and a non-volatile memory unit that share common access lines and control logic, merging two previously separate functions into one compact unit that achieves both fast search and non-volatile storage without requiring separate SRAM blocks
Solution Approach 2:
The CAM cell is designed to perform multiple functions: it stores non-volatile data, enables fast content-addressable search, and provides configurability through multiple operational modes (NOR-type and NAND-type match line arrays). The single cell structure serves as both memory storage and search comparator, eliminating the need for separate SRAM-based search units
2Speed
If SRAM-based CAM cells are used, then search operation speed is improved, but power consumption increases
Solution Approach 1:
The non-volatile memory unit maintains data without requiring continuous power, only consuming energy during periodic write operations to configure the stored data. This eliminates the continuous power consumption characteristic of SRAM cells while maintaining the ability to perform fast search operations when needed
Solution Approach 2:
The non-volatile memory component retains its stored data automatically without requiring continuous power supply or refresh operations. The CAM cell leverages this self-retaining property to eliminate the need for continuous power consumption while maintaining search capability through the integrated search unit
3Adaptability or versatility
If conventional CAM cells are used, then content search capability is provided, but scalability to high-density arrays is limited
Solution Approach 1:
The patent implements scalability through modular array configurations where multiple identical CAM cell units can be arranged in NOR-type or NAND-type match line arrays. Each cell maintains the same basic structure and functionality, allowing linear scaling of memory capacity without increasing cell complexity or sacrificing search performance
Solution Approach 2:
The invention enables high-density array formation by organizing CAM cells into two-dimensional match line arrays with multiple rows and columns. The NOR-type and NAND-type configurations allow flexible spatial arrangement that maximizes density while maintaining accessible search paths, effectively utilizing silicon real estate compared to conventional single-configurations
4Speed
If SRAM-based CAM cells are used, then fast search operation is achieved, but silicon area usage increases
Solution Approach 1:
The patent merges the SRAM search comparator functionality with non-volatile memory storage in a single integrated cell, eliminating the need for separate SRAM blocks. This consolidation reduces the total silicon area required for high-density CAM arrays while maintaining fast search operation speeds through the integrated search unit
Data Source
AI summary
A Configurable Non-Volatile Content Addressable Memory (CNVCAM) cell consisting of a pair of complementary non-volatile memory devices and a MOSFET (Metal-Oxide-Semiconductor-Field-Effect-Transistor) is disclosed. The CNVCAM cells can be constructed to form the NOR-type match line memory array and the NAND-type match line memory array. In contrast to the Random Access Memory (RAM) accessed by the address codes with the prior knowledge of memory locations, CNVCAM can be pre-configured into non-volatile memory content data and searched by an input content data to trigger the further computing process. The unique property of CNVCAM can provide a key component for neural computing.