Memory Index Mapping for DNN Fault Tolerance

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Solution Overview

Problem

Deep neural network operations require large memory space to store weights, and stuck-at-faults in memory can lead to incorrect operations, necessitating a solution to reduce faults and improve accuracy.

Innovation Solution

A memory system with a processing unit and a weight unit that includes an index memory and a mapping table, where weight indexes are mapped to representative weight data to reduce memory usage and detect and minimize stuck-at-faults by selecting coded data with the least faults.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If memory space is reduced by grouping weight values into representative data, then memory capacity requirements are decreased, but the risk of stuck-at-faults affecting operation accuracy increases

Engineering Contradiction:
Improvememory spaceVSAvoidoperation accuracy
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The patent segments the weight storage into two parts: an index memory storing compact weight indexes and a mapping table storing the mapping relationships. This segmentation allows the system to reduce memory space while maintaining reliability by separating the compact storage function from the mapping function, enabling fault detection and correction mechanisms to operate on the mapping table without affecting the compactness of weight storage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a mapping table as an intermediary between the index memory and the actual weight values. This mapping table acts as a buffer that can detect and correct stuck-at-faults, preventing them from directly affecting the neural network operation accuracy while maintaining the space efficiency of index-based storage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If mapping table is created by detecting faults and selecting coded data with least stuck-at-faults, then operation accuracy is improved, but the complexity of memory initialization increases

Engineering Contradiction:
Improveoperation accuracyVSAvoidmemory initialization complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs fault detection and mapping table creation as preliminary actions during system initialization or manufacturing. By detecting stuck-at-faults in advance and creating an optimized mapping table before actual operation, the system eliminates the need for complex real-time fault handling during neural network computation, thus improving operational accuracy without significantly impacting runtime performance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs self-diagnosis by automatically detecting stuck-at-faults in the index memory and autonomously generating an optimized mapping table that avoids faulty locations. This self-service approach eliminates the need for external manual configuration or complex external fault handling mechanisms, balancing improved reliability with acceptable initialization complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS20220019881A1Memory for performing deep neural network operation and operating method thereof
Publication Date: 2022.01.20 WINBOND ELECTRONICS CORP
  • US20220019881A1 patent drawing
  • US20220019881A1 patent drawing
  • US20220019881A1 patent drawing

AI summary

A memory is suitable for performing a deep neural network operation. The memory includes: a processing unit and a weight unit. The processing unit includes a data input terminal and a data output terminal. The weight unit is configured to be coupled to the data input terminal of the processing unit. The weight unit includes an index memory and a mapping table. The index memory is configured to store multiple weight indexes. The mapping table is configured to respectively map the multiple weight indexes to multiple representative weight data.