Memory Circuit Reference Cell Testing via Sense Amplifier

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Solution Overview

Problem

Existing memory circuits face inefficiencies in testing reference cells used for generating reference potentials, leading to potential logic inversion errors during readout operations, which necessitate frequent testing and dedicated sense amplifiers, resulting in increased circuit overhead and area requirements.

Innovation Solution

A memory circuit design that includes multiple memory arrays, a selection circuit to select and supply values to a sense amplifier with input terminals, and output switches to control the output from memory cells, allowing for efficient testing and amplification of reference potentials, thereby improving readout reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dedicated sense amplifier is prepared for reading out reference cells, then the reliability of reference cell testing is improved, but the circuit area is enlarged

Engineering Contradiction:

Improvereference cell testing reliabilityVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The sense amplifier is designed to perform multiple functions: it can read out both data cells and reference cells using the same amplifier circuit. The control circuit manages the switching between these functions, allowing one sense amplifier to replace what would traditionally require separate dedicated amplifiers for reference cell testing, thereby reducing circuit area while maintaining testing reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

A control circuit is introduced as an intermediary component that coordinates the operation of the sense amplifier between reading data cells and testing reference cells. This control mechanism enables the sense amplifier to be dynamically allocated to different tasks, achieving reliable reference cell testing without requiring a permanently dedicated amplifier

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If reference cells are tested at predetermined intervals, then the circuit complexity is reduced, but the reliability of readout data deteriorates due to potential logic inversion errors

Engineering Contradiction:

Improvecircuit complexityVSAvoidreadout data reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system performs preliminary testing of reference cells by incorporating testing into the normal readout operation flow. The control circuit enables reference cell testing to be conducted proactively before data readout operations that would depend on those reference cells, preventing logic inversion errors from propagating without requiring complex dedicated testing schedules

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sense amplifier continuously performs useful actions by alternating between reading data cells and testing reference cells based on control signals. This continuous operational mode ensures reference cells are regularly tested without idle periods, maintaining reliability while keeping the circuit design relatively simple through efficient resource utilization

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If multiple memory arrays are used with selection circuit, then the efficiency of reference cell testing is improved, but the device complexity increases

Engineering Contradiction:

Improvereference cell testing efficiencyVSAvoiddevice complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The memory system is segmented into multiple memory arrays, with each array containing both data cells and reference cells. The selection circuit is configured to selectively access reference cells from different arrays, enabling parallel or sequential testing of reference cells across multiple arrays, which improves testing efficiency while distributing the complexity across modular units

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed solution enables efficient testing of reference cells, reducing the likelihood of logic inversion errors and improving the reliability of readout data while minimizing circuit overhead and area requirements.

Implementation Method 1

a sense amplifier that has a first input terminal and a second input terminal and that is configured to amplify and output the first value supplied to the first input terminal in reference to the second value supplied to the second input terminal

Methodology Applied

Scientific EffectSignal amplification:

Data Source

PatentUS11367496B2Memory circuit

Publication Date: 2022.06.21 SONY SEMICON SOLUTIONS CORP

AI summary

The reference cells used for reading out data are tested efficiently so as to improve the reliability of the readout data. A memory circuit includes multiple memory arrays, a selection circuit, and a sense amplifier. The selection circuit selects values output from memory cells in any of the multiple memory arrays so as to supply a first value and a second value. A sense amplifier has a first input terminal and a second input terminal. The sense amplifier amplifies and outputs the first value supplied to the first input terminal in reference to the second value supplied to the second input terminal.