On-Chip NVM Search Circuitry for Reduced Data Transfer

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Solution Overview

Problem

In data storage devices like SSDs with non-volatile memory arrays, searching for specific data within a range of logical block addresses often involves fetching and processing unnecessary data, leading to inefficient processing times and decreased endurance of the memory dies due to excessive read cycles.

Innovation Solution

Implementing on-chip search circuitry within the non-volatile memory die to determine whether to search using internal circuitry or a controller-based approach, allowing for selective data transfer and processing only the relevant data, thereby reducing unnecessary data fetching and enhancing processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the host fetches all data from the NVM array corresponding to the LBA range for searching, then the search can be performed, but considerable unnecessary data is transferred and processed, wasting time and energy

Engineering Contradiction:
Improvesearch efficiencyVSAvoiddata transfer time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent extracts and implements search functionality directly within the NVM array die, allowing the search operation to be performed on the stored data without first transferring all data to the host. This extraction of the search function to the storage device itself eliminates the unnecessary data transfer step, improving search efficiency while reducing data transfer time.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If the host fetches all data from the NVM array for searching, then the search can be completed, but excessive read cycles decrease the endurance of the memory dies

Engineering Contradiction:
Improvesearch completionVSAvoidmemory die endurance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The search function is extracted from the host system and implemented within the NVM array die. This allows search operations to be performed using internal read cycles that do not contribute to the wear of the memory cells, as the search reads are performed during normal operation rather than requiring additional transfer cycles that increase overall stress on the system.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If on-chip search circuitry is implemented within the NVM die, then search performance is improved and data transfer is reduced, but the device complexity increases

Engineering Contradiction:
Improvesearch performanceVSAvoidNVM die structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The NVM array die is designed to perform multiple functions: both data storage and data search operations. By integrating search circuitry into the existing NVM die architecture, the same hardware structure serves dual purposes, improving search performance while minimizing the increase in device complexity through multi-functional design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3920050B1On-chip non-volatile memory (NVM) search
Publication Date: 2023.11.01 WESTERN DIGITAL TECHNOLOGIES INC
  • EP3920050B1 patent drawingFigure 1
  • EP3920050B1 patent drawingFigure 2
  • EP3920050B1 patent drawingFigure 3

AI summary

The disclosure relates in some aspects to on-chip processing circuitry formed within the die of a non-volatile (NVM) array to perform data searches. In some aspects, the die includes components configured to sense wordlines of stored data in the NVM array by applying voltages on the wordlines serially, and then search for an input data pattern within the serially-sensed wordlines. In some examples, the components of the die include latches and circuits configured to perform bitwise latch logic search operations. In other examples, the search components are configured with under-the-array or next-to-the-array dedicated search circuitry that uses registers and/or random access memory (RAM). Other aspects relate to a separate controller device for controlling the on-chip NVM search operations. For example, the controller may determine whether to search for data using search components of the NVM die or processors of the controller based, e.g., on a degree of fragmentation of data.