Memory Refresh Command Verification via Register Comparison

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Solution Overview

Problem

Conventional memory devices require periodic refresh commands to mitigate leakage current, typically verified at low speed and high temperature due to memory cell properties and test costs, necessitating an alternative method for efficient testing.

Innovation Solution

A method and system that generate and compare refresh commands and address information to assess memory device functionality, allowing for high-speed and low-temperature verification through a test equipment and memory device interaction, including a register and refresh circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If memory devices are tested at high temperature and low speed to verify refresh commands, then the testing is more reliable for detecting leakage current issues, but the testing efficiency and productivity are reduced

Engineering Contradiction:

Improverefresh command verification reliabilityVSAvoidtesting efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-loading expected refresh address information into a register before the actual refresh operation. This allows the refresh command to be verified by comparing the actual address information with the pre-prepared expected values, enabling faster and more reliable testing without requiring high temperature and low speed conditions.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If memory devices are tested at low speed and high temperature, then leakage current issues can be detected more effectively, but the test cost increases

Engineering Contradiction:

Improveleakage current detection accuracyVSAvoidtest cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses copying by creating a copy of the expected refresh address information and storing it in a register for comparison purposes. This allows the actual refresh operation to be verified against the copied expected values, enabling accurate leakage current detection at normal operating conditions rather than requiring expensive high temperature testing.

Inventive Principle:

Principle #26Copying

3Reliability

If conventional refresh command verification methods are used, then memory cell data protection can be ensured, but the testing process is time-consuming and inefficient

Engineering Contradiction:

Improvedata protection verificationVSAvoidtesting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements feedback by comparing the actual refresh address information with the expected address information that was pre-loaded into the register. This feedback mechanism provides immediate verification of whether the refresh command executed correctly, ensuring data protection while significantly reducing testing time compared to conventional methods.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11621052B1Method for testing memory device and test system

Publication Date: 2023.04.04 NAN YA TECH

AI summary

A method for testing a memory device includes the following steps of: generating a first refresh command to the memory device; storing a first refresh address information into a register of the memory device according to the first refresh command; reading out the first refresh address information according to a mode register read command; comparing the first refresh address information with an expectation address information to generate a comparison result; and generating a second refresh command to the memory device or screening out the memory device according to the comparison result.