Wordline Driver Voltage Adjustment for Memory Cell Noise Margin

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Solution Overview

Problem

The challenge in memory devices is to address the static noise margin (SNM) issue to allow for lower operating voltages while minimizing the impact on data storage, particularly in wireless communication devices where low power consumption is crucial.

Innovation Solution

A memory cell with a wordline driver that adjusts the voltage level of the wordline based on feedback to compensate for the parameters of the memory cell transistor, such as speed and threshold voltage, to improve SNM and reduce noise susceptibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the operating voltage of the memory is reduced to lower power consumption, then power efficiency is improved, but the static noise margin deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidstatic noise margin
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent adjusts the wordline voltage parameter dynamically to compensate for transistor threshold voltage variations. By changing the wordline voltage level based on detected transistor characteristics, the system maintains adequate noise margin while operating at lower supply voltages, thus resolving the contradiction between power consumption and reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the actual transistor threshold voltage is detected and used to adjust the wordline driver output. This closed-loop control ensures that the wordline voltage is optimized for each transistor's characteristics, maintaining reliable operation at lower operating voltages and improving the static noise margin without increasing power consumption

Inventive Principle:
Principle #23Feedback

2Reliability

If the wordline voltage is adjusted to compensate for transistor parameter variations, then the static noise margin is improved, but the device complexity increases

Engineering Contradiction:
Improvestatic noise marginVSAvoidwordline driver complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs self-service principles where the system automatically detects transistor threshold voltage variations and adjusts the wordline voltage without external intervention. The detection and adjustment mechanisms are integrated into the existing memory structure, allowing the system to self-optimize its performance without adding significant external control complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent merges the voltage adjustment function with the existing wordline driver structure. By integrating the compensation mechanism into the driver itself rather than adding separate external control circuits, the patent improves noise margin while minimizing the increase in overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3437098B1Wordline adjustment scheme
Publication Date: 2019.07.24 QUALCOMM INC
  • EP3437098B1 patent drawingFigure 1
  • EP3437098B1 patent drawingFigure 2
  • EP3437098B1 patent drawingFigure 3

AI summary

A memory and a method for operating a memory are provided. The memory includes a memory cell having a transistor and a wordline driver outputting a wordline coupled to the memory cell. The wordline driver adjusts a voltage level of the wordline to compensate for a parameter of the transistor. The method includes asserting a wordline voltage to access a memory cell having a transistor and adjusting the wordline voltage to compensate for a parameter of the transistor. Another memory is provided. The memory includes a memory cell and a wordline driver outputting a wordline coupled to the memory cell. The wordline driver adjusts a voltage level of the wordline based on a feedback of the wordline.