Command Address Input Buffer 2N Mode for Bias Current Reduction

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Solution Overview

Problem

Semiconductor memory devices, particularly DDR5 SDRAM, face challenges in maintaining stable operation at high clock frequencies due to high input buffer bias current requirements in 1N mode, leading to instability in command switching.

Innovation Solution

Implementing a 2N mode that skips clock cycles between commands, allowing the input buffer to operate at a lower switching rate and reduce bias current, thereby stabilizing operation while reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If 1N mode is used to read commands on every clock cycle, then productivity is improved, but input buffer bias current increases and stability deteriorates

Engineering Contradiction:
Improvecommand reading speedVSAvoidcommand switching stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system dynamically switches between 1N mode (reading commands on every clock cycle) and 2N mode (skipping clock cycles between commands) based on operational requirements. This dynamic mode selection allows the input buffer to operate at different switching rates, reducing bias current when high-speed command reading is not critical, thereby resolving the contradiction between productivity and stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operating parameters of the input buffer by adjusting the clock cycle skipping behavior. In 2N mode, the input buffer skips clock cycles between commands, effectively reducing its switching rate and bias current consumption. This parameter change allows the system to maintain acceptable command reading performance while improving stability and reducing power consumption.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If input buffer switching rate is increased to maintain 1N mode, then productivity is improved, but use of energy increases

Engineering Contradiction:
Improvecommand processing throughputVSAvoidinput buffer bias current
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system implements periodic action by having the input buffer skip clock cycles between command readings in 2N mode. This periodic skipping reduces the average switching rate of the input buffer, thereby reducing bias current consumption while still maintaining the ability to process commands at required intervals. The periodic nature of this action resolves the contradiction between productivity and energy use.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the input buffer's operating mode between 1N and 2N based on workload and performance requirements. When high throughput is needed, 1N mode is used with higher bias current; when power savings are prioritized, 2N mode is used with reduced bias current. This dynamic adaptation resolves the contradiction between productivity and energy consumption.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If clock cycles are skipped between commands in 2N mode, then use of energy is reduced, but productivity decreases

Engineering Contradiction:
Improveinput buffer bias currentVSAvoidcommand reading speed
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The system applies partial action by skipping only some clock cycles between commands rather than all clock cycles. In 2N mode, the input buffer operates at a reduced switching rate by skipping alternating clock cycles, which reduces energy consumption while still maintaining sufficient command processing throughput for many applications. This partial reduction in switching activity resolves the contradiction between energy use and productivity.

Inventive Principle:
Principle #16Partial or excessive action

4Productivity

If input buffer operates at high switching rate, then productivity is improved, but heat generation increases

Engineering Contradiction:
Improvecommand processing speedVSAvoiddevice heat generation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

By implementing periodic skipping of clock cycles in 2N mode, the input buffer's switching activity is reduced, which directly reduces power dissipation and heat generation. The periodic nature of this skipping allows the device to maintain acceptable command processing speed while significantly reducing thermal output, resolving the contradiction between productivity and temperature.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3625799B1Command address input buffer bias current reduction
Publication Date: 2025.09.10 LODESTAR LICENSING GROUP LLC
  • EP3625799B1 patent drawingFigure 1
  • EP3625799B1 patent drawingFigure 2
  • EP3625799B1 patent drawingFigure 3

AI summary

A memory device (10) may include one or more memory banks (12) that store data and one or more input buffers (50). The input buffers (50) may receive command address signals to access the one or more memory banks (12). The memory device (10) may operate in one of a first mode of operation or a second mode of operation. The one or more input buffers (50) may operate under a first bias current when the memory device (10) is in the first mode of operation or a second bias current when the memory device (10) is in the second mode of operation, and the first bias current may be greater than the second bias current.