Trimming Data Read Control Circuit for Nonvolatile Memory

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Solution Overview

Problem

The variability in manufacturing processes leads to variations in the output voltage of charge pumps and reference currents in nonvolatile memory chips, causing read disturb issues that result in erroneous trimming data reading and deteriorated circuit characteristics.

Innovation Solution

A data processing device with a nonvolatile memory and a trimming data read control circuit that randomly selects one of multiple memory regions to read trimming data, reducing the frequency of access to each region and minimizing read disturb effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If trimming data is read from the EXTRA region at every power-on, then circuit characteristics can be trimmed to optimum values, but read disturb causes data characteristics to vary and read errors occur

Engineering Contradiction:

Improveread accuracy of trimming dataVSAvoidread disturb effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the storage of trimming data across multiple memory regions (first EXTRA region and second EXTRA region) instead of storing it in a single region. This segmentation reduces the frequency of access to each individual region, thereby minimizing read disturb effects on any single memory region while ensuring trimming data can still be retrieved.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of memory region selection from fixed to variable. By randomly selecting between the first and second EXTRA regions for storing and reading trimming data, the access frequency to each region is equalized and reduced, mitigating read disturb effects while maintaining trimming functionality.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If multiple memory regions are used to store trimming data, then read disturb is reduced, but device complexity increases

Engineering Contradiction:

Improveread accuracy of trimming dataVSAvoidmemory region management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a random selection mechanism (controlled by control signal EXSEL) to choose between multiple memory regions, avoiding the need for complex management logic. This approach reduces device complexity while still achieving the goal of reducing read disturb effects through distributed storage.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If trimming data is read from a fixed memory region, then access is simple, but read disturb causes data characteristics to vary

Engineering Contradiction:

Improveaccess simplicityVSAvoidread disturb effect

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent segments the trimming data storage across multiple memory regions (first and second EXTRA regions), allowing simple access to any region while reducing the cumulative read disturb effect on any single region through distributed access patterns.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8289778B2Data processing device and method of reading trimming data

Publication Date: 2012.10.16 RENESAS ELECTRONICS CORP

AI summary

A data processing device according to the present invention comprises a nonvolatile memory and a trimming data read control circuit. The nonvolatile memory has a plurality of memory regions in which the same trimming data is stored. The trimming data read control circuit reads the trimming data from a random one of the plurality of memory regions.