Flash Memory String Selecting Voltage Temperature Compensation

Solution Overview

Problem

Conventional flash memory devices have a limited string selecting control voltage window that narrows with ambient temperature variations, leading to poor control of string selecting switches and reduced writing operation performance.

Innovation Solution

A flash memory device with a string selecting control voltage generator that adjusts the control voltage based on ambient temperature, using a temperature compensation scheme to maintain an adequate voltage window for inhibiting, programming, or quick pass writing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the string selecting control voltage is isolated from ambient temperature, then the device structure is simple, but the voltage window becomes too narrow when ambient temperature varies

Engineering Contradiction:

Improvedevice structureVSAvoidvoltage window width

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the string selecting control voltage based on ambient temperature. The voltage generator modifies the voltage parameter in response to temperature variations, ensuring the voltage window remains within an appropriate range across different operating conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by using a temperature sensor to detect ambient temperature and feeding this information back to the voltage generator. The voltage generator then adjusts the string selecting control voltage according to the detected temperature, creating a closed-loop control system that maintains optimal voltage window width.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the string selecting control voltage is adjusted according to ambient temperature, then the voltage window is maintained, but the device complexity increases

Engineering Contradiction:

Improvevoltage window widthVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by using a temperature sensor to detect ambient temperature and feeding this information back to the voltage generator. The voltage generator then adjusts the string selecting control voltage according to the detected temperature, creating a closed-loop control system that maintains optimal voltage window width.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces a temperature sensor as an intermediary component that bridges the ambient temperature environment and the voltage generation system. This intermediary enables indirect control of the voltage window width through temperature-dependent voltage adjustment without requiring direct mechanical or structural modifications to the memory cell strings.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the voltage window is narrow, then the device structure is simple, but the string selecting switches cannot be well controlled

Engineering Contradiction:

Improvevoltage control systemVSAvoidswitch control performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the string selecting control voltage based on ambient temperature. The voltage generator modifies the voltage parameter in response to temperature variations, ensuring the voltage window remains within an appropriate range across different operating conditions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11270755B1Flash memory device and control method

Publication Date: 2022.03.08 MACRONIX INTERNATIONAL CO LTD

AI summary

A memory cell strings respectively have a plurality of string selecting switches, wherein the plurality of string selecting switches are controlled by a string selecting control voltage. The string selecting control voltage generator is coupled to the memory cell strings, and generate the string selecting control voltage according to an ambient temperature during a writing operation performed on the plurality of memory cell strings. Wherein each of the plurality of memory cell strings is inhibited, programmed or quick pass written during the writing operation.