DRAM Refresh Voltage Control Circuit

Solution Overview

Problem

Dynamic random access memory (DRAM) devices lose data over time due to power supply, necessitating periodic refresh operations to sense and amplify stored data levels, which can lead to inefficiencies and increased power consumption.

Innovation Solution

A device with an operation control circuit and drive control signal generation circuit that generates internal refresh signals and control signals to manage active voltage supplied to word lines during refresh operations, optimizing voltage levels to reduce power consumption and prevent data loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If refresh operations are performed periodically to sense and amplify data levels, then data retention is improved, but power consumption increases

Engineering Contradiction:

Improvedata retentionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the active voltage level adjustable rather than fixed. The voltage supplied to word lines is dynamically changed based on the refresh operation state - using higher voltage during refresh operations to ensure proper sensing and amplification, and lowering voltage during non-refresh periods to reduce power consumption. This dynamic adjustment resolves the contradiction between maintaining data retention reliability and reducing overall power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the voltage parameter of the active signal supplied to word lines based on operational requirements. During refresh operations, the voltage is set to a first level sufficient for proper sensing and amplification. During non-refresh operations, the voltage is reduced to a second level to minimize power consumption. This parameter change approach allows the system to maintain data retention when needed while significantly reducing power consumption during idle periods.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If active voltage is supplied continuously to word lines, then data retention is maintained, but current leakage increases

Engineering Contradiction:

Improvedata retentionVSAvoidcurrent leakage

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements periodic action by supplying active voltage to word lines only during refresh operations rather than continuously. The voltage is activated periodically at specific intervals when refresh operations are needed, and deactivated during non-refresh periods. This periodic activation pattern maintains data retention through regular refresh cycles while eliminating continuous current leakage that would occur with constant voltage supply.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the voltage supply to word lines conditional and variable. The voltage is dynamically activated only when refresh operations are performed, rather than being continuously supplied. This dynamic control allows the system to maintain data retention through periodic refresh operations while avoiding continuous current leakage associated with constant voltage supply.

Inventive Principle:

Principle #15Dynamics

3Reliability

If standard refresh operations are performed without voltage adjustment, then data retention is ensured, but power consumption cannot be optimized

Engineering Contradiction:

Improvedata retentionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent changes the voltage parameter of the active signal supplied to word lines based on operational requirements. During refresh operations, the voltage is set to a first level sufficient for proper sensing and amplification. During non-refresh operations, the voltage is reduced to a second level to minimize power consumption. This parameter change approach allows the system to maintain data retention when needed while significantly reducing power consumption during idle periods.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by making the voltage supply adaptive rather than static. The voltage level is dynamically adjusted based on whether the system is performing refresh operations or is in idle state. This dynamic voltage adjustment enables the system to optimize power consumption while ensuring data retention during refresh operations, resolving the contradiction between reliability and energy efficiency.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11315621B2Devices adjusting a level of an active voltage supplied in a refresh operation

Publication Date: 2022.04.26 SK HYNIX INC

AI summary

A device includes an operation control circuit and a drive control signal generation circuit. The operation control circuit generates an internal refresh signal that is activated to perform an active operation for a cell array, the cell array being coupled to a word line that is selected by a row address based on a refresh signal that is activated to perform a refresh operation. In addition, the operation control circuit generates a pre-refresh pulse based on the refresh signal and generates a refresh end pulse based on the internal refresh signal. The drive control signal generation circuit generates a drive control signal to control a drive of an active voltage that is supplied to the word line that is selected by the row address based on the internal refresh signal, the pre-refresh pulse, and the refresh end pulse.