Semiconductor Memory Bouncing Detection Circuit

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Solution Overview

Problem

Source line bouncing in semiconductor memory devices interferes with the normal sensing of threshold voltage, leading to inaccurate data reading due to current leakage issues when multiple cell strings are coupled in common, affecting the efficiency of current sensing methods.

Innovation Solution

A semiconductor memory device with a bouncing detection circuit that compares the voltage of the common source line to a reference voltage, allowing for selective use of a multi-sensing method by adjusting the number of sensing operations based on detection signals, thereby reducing unnecessary sensing time and improving data reading accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple cell strings are coupled in common to share the common source line, then device integration is improved, but source line bouncing occurs causing sensing accuracy to deteriorate

Engineering Contradiction:

Improvedevice integrationVSAvoidsensing accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the sensing process into multiple stages: a first sensing operation to detect source line bouncing, and a second sensing operation to accurately read data only when bouncing is absent. This segmentation allows the system to maintain high integration while preserving sensing accuracy by adaptingively selecting when to perform accurate sensing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic sensing where the number of sensing operations is adjusted based on real-time detection of source line bouncing. The control circuit dynamically determines whether to perform one or two sensing operations, optimizing between speed and accuracy based on actual operating conditions rather than using a fixed sensing protocol.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If a first sensing operation is performed to detect source line bouncing, then sensing accuracy is improved, but sensing time increases due to additional operations

Engineering Contradiction:

Improvesensing accuracyVSAvoidsensing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by performing only the necessary sensing operations based on detected conditions. When source line bouncing is detected in the first sensing operation, the system performs an additional sensing operation. When no bouncing occurs, the system skips the second operation, thus performing only the partial action needed to maintain accuracy without unnecessary time loss.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent uses feedback from the first sensing operation to control the second sensing operation. The result of detecting source line bouncing in the first operation feeds back to the control circuit, which then determines whether to execute the second sensing operation, creating a closed-loop system that optimizes sensing time based on actual conditions.

Inventive Principle:

Principle #23Feedback

3Power

If the voltage of the common source line rises due to source line bouncing, then current flows into the common source line, but current leakage occurs preventing normal threshold voltage sensing

Engineering Contradiction:

Improvecurrent flowVSAvoidthreshold voltage sensing

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

The patent performs a preliminary sensing operation before the main data reading operation to detect source line bouncing. By detecting the voltage rise and current leakage conditions in advance, the system can determine whether to proceed with accurate data sensing, preventing wasted operations when conditions are unfavorable for accurate threshold voltage measurement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of source line bouncing into a useful detection signal. The voltage rise and current leakage that normally degrade sensing accuracy are harnessed as indicators to trigger an additional sensing operation, transforming a harmful phenomenon into a mechanism that preserves overall sensing accuracy through adaptive re-sensing.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively reduces sensing time and enhances data reading accuracy by detecting source line bouncing and adjusting sensing operations, ensuring accurate threshold voltage sensing even in the presence of common source line voltage rises.

Implementation Method 1

a bouncing detection circuit that compares a voltage supplied to the common source line and a reference voltage

Methodology Applied

Scientific EffectVoltage comparison: Ohm's Law

Data Source

PatentUS9159435B2Semiconductor memory device having bouncing detection circuit and method of operating the same

Publication Date: 2015.10.13 SK HYNIX INC

AI summary

The semiconductor memory device includes a memory cell array that includes a plurality of cell strings coupled between a common source line and a plurality of bit lines, a peripheral circuit that reads data stored in a selected memory cell, a bouncing detection circuit that compares a voltage supplied to the common source line and a reference voltage to thereby output a detection signal while performing a reading operation, and a control circuit that controls the peripheral circuit in order to perform the reading operation by adjusting the number of sensing operation times in accordance with the detection signal.