Diagonal Memory Block Protection Data Programming

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Solution Overview

Problem

Existing flash memory devices face inefficiencies in reading and storing protection data for memory blocks, particularly when protecting large numbers of blocks, as current methods require multiple page reads, which can exceed power-up time limits and are prone to errors due to improper programming.

Innovation Solution

Diagonal programming of protection data across even or odd pages allows for faster and more accurate reading using an erase verify operation, where protection data is stored in bytes across multiple pages, enabling a single operation to read all protection data and reducing errors by analyzing majority bits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple page reads are used to read protection data for many memory blocks, then all protection data can be read, but the power-up time exceeds the typical 1 ms limit

Engineering Contradiction:

Improveprotection data reading completenessVSAvoidpower-up time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The protection data is segmented and stored diagonally across multiple pages, but the reading process segments the operation into a single erase verify cycle that efficiently retrieves all protection data without requiring multiple sequential page reads, thus reducing power-up time while maintaining complete protection data reading

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the reading approach from a sequential page-by-page read operation to a diagonal erase verify operation that accesses protection data across multiple pages simultaneously, effectively adding a dimensional approach to data retrieval that reduces the time required during power-up

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If protection data is stored in a conventional manner, then storage is simple, but reading accuracy is reduced due to improper programming errors

Engineering Contradiction:

Improveprotection data storage simplicityVSAvoidprotection data reading accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The erase verify operation provides feedback by reading back the protection data and comparing it against expected values, allowing the system to detect and correct improper programming errors, thus improving reading accuracy while maintaining the simplicity of the storage structure

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the reading parameter from a standard page read operation to an erase verify operation, which uses different voltage conditions and read thresholds optimized for detecting protection data, thereby improving reading accuracy without complicating the storage method

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8886876B2Protecting groups of memory cells in a memory device

Publication Date: 2014.11.11 MICRON TECHNOLOGY INC

AI summary

Methods for memory block protection and memory devices are disclosed. One such method for memory block protection includes programming protection data to protection bytes diagonally across different word lines of a particular memory block (e.g., Boot ROM). The protection data can be retrieved by an erase verify operation that can be performed at power-up of the memory device.