TCAM Memory Array for Large Search Word Similarity Matching

Solution Overview

Problem

Current systems face inefficiencies in processing large data sets due to the need for substantial data movement and high power consumption when transferring data between nonvolatile memory and digital processing systems, limiting their throughput and efficiency.

Innovation Solution

A ternary content addressable memory (TCAM) technology that supports very large search words by using a memory array with TCAM cells configured to store ternary states, allowing for similarity matching rather than exact matches, which reduces data transfer requirements and improves processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data is transferred from nonvolatile memory to digital processing system for processing, then processing capability is improved, but data transfer time and power consumption increase

Engineering Contradiction:

Improveprocessing capabilityVSAvoiddata transfer time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent combines the storage function (nonvolatile memory) and processing function (TCAM similarity matching) into a single integrated system. The TCAM is built directly within the nonvolatile memory array, allowing similarity matching operations to be performed in-place without transferring data to external digital processing systems, thus eliminating data transfer time while maintaining processing capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces TCAM as an intermediary component between nonvolatile memory and digital processing systems. The TCAM performs preliminary similarity matching filtering on stored data, identifying only those data items that match the search criteria within a specified mismatch threshold. This intermediary processing step reduces the volume of data that needs to be transferred to digital systems, thereby reducing data transfer time

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If data is transferred from nonvolatile memory to digital processing system for processing, then processing capability is improved, but power consumption increases

Engineering Contradiction:

Improveprocessing capabilityVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent combines the storage function (nonvolatile memory) and processing function (TCAM similarity matching) into a single integrated system. The TCAM is built directly within the nonvolatile memory array, allowing similarity matching operations to be performed in-place without transferring data to external digital processing systems, thus eliminating data transfer time while maintaining processing capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces TCAM as an intermediary component between nonvolatile memory and digital processing systems. The TCAM performs preliminary similarity matching filtering on stored data, identifying only those data items that match the search criteria within a specified mismatch threshold. This intermediary processing step reduces the volume of data that needs to be transferred to digital systems, thereby reducing data transfer time

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If exact match is required for search operations, then search precision is improved, but data transfer volume increases

Engineering Contradiction:

Improvesearch precisionVSAvoiddata transfer volume

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies partial matching instead of requiring complete exact matches. The TCAM allows searches with a specified number of mismatches (threshold), returning data items that partially match the search criteria. This partial matching approach maintains sufficient search precision for many applications while dramatically reducing the number of data items that need to be transferred for further processing

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20240386923A1Content addressable memory for large search words

Publication Date: 2024.11.21 MACRONIX INTERNATIONAL CO LTD

AI summary

A memory array is arranged to store data words in respective sets of TCAM cells, where each TCAM cell is configured to store ternary states of a bit of the stored word. A circuit to select a set of TCAM cells in the set of TCAM cells, such as decoders and drivers for word lines, bit lines, block select gates. A circuit to apply an input search word to the TCAM cells in the selected set of TCAM cells, such as a search word buffer or driver on one of word lines or bit lines for the array. A circuit to generate an output indicating similarity of the stored word in the selected set of TCAM cells to the input search word, based on mismatch or possible mismatch of more than one bit of the search word.