NAND Wordline Pre-Charging for Faster Memory Setup

Solution Overview

Problem

As the number of stacked word lines increases in memory devices, the capacitance and power consumption of word lines also increase, necessitating a faster word line setup time to improve read and verification operations.

Innovation Solution

Pre-charging the common source line during word line setup to reduce the number of activated charge pumps, thereby decreasing power consumption and shortening the word line setup time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of stacked word lines increases, then the memory integration degree increases, but the capacitance and power consumption of word lines increase

Engineering Contradiction:

Improvenumber of stacked word linesVSAvoidpower consumption of word lines

Core Design Contradiction:

Quantity of substanceVSUse of energy by stationary object

Solution Approach 1:

The common source line is pre-charged to a first pass voltage before the read operation begins. This preliminary action reduces the voltage difference that needs to be overcome during word line setup, thereby reducing the power consumption and setup time when activating multiple stacked word lines

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If the number of stacked word lines increases, then the memory integration degree increases, but the word line setup time increases

Engineering Contradiction:

Improvenumber of stacked word linesVSAvoidword line setup time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The common source line is pre-charged to a first pass voltage before the read operation begins. This preliminary action reduces the voltage difference that needs to be overcome during word line setup, thereby reducing the setup time when activating multiple stacked word lines

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The voltage on the common source line is dynamically adjusted during the read operation. It is pre-charged to a first pass voltage during setup, then increased to a second pass voltage during the read operation, optimizing both setup time and read performance

Inventive Principle:

Principle #15Dynamics

3Speed

If more charge pumps are activated to reduce word line setup time, then the word line setup time decreases, but the power consumption increases

Engineering Contradiction:

Improveword line setup speedVSAvoidpower consumption of charge pumps

Core Design Contradiction:

SpeedVSUse of energy by stationary object

Solution Approach 1:

The common source line is pre-charged to a first pass voltage before the read operation begins. This preliminary action reduces the voltage difference that needs to be overcome during word line setup, thereby reducing the power consumption and setup time when activating multiple stacked word lines

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The voltage on the common source line is dynamically adjusted during the read operation. It is pre-charged to a first pass voltage during setup, then increased to a second pass voltage during the read operation, optimizing both setup time and read performance

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP4398251B1NAND memory device wordlines pre-charging and operating method of the same

Publication Date: 2025.10.15 SAMSUNG ELECTRONICS CO LTD

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AI summary

A method of operating a memory device, the method includes applying a pass voltage to a plurality of word lines during a word line setup period, applying an on-voltage to an unselected ground select line at a first time point during the word line setup period, increasing a voltage of the plurality of word lines by applying a pre-charge voltage to the common source line at a second time point during the word line setup period, applying an off-voltage to the unselected ground select line at a third time point during the word line setup period, and applying a ground voltage to the common source line at a fourth time point during the word line setup period.