Selective Bit Line Precharge for Digital Memory Power Reduction

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Solution Overview

Problem

Current digital memory architectures consume excessive power due to the need to precharge all bit lines before each access cycle, which is inefficient, especially when only a subset of bit lines are accessed, and result in increased latency and power consumption, particularly in mobile and communication applications where random access is required.

Innovation Solution

The solution involves selectively precharging only the subset of bit lines needed for access, allowing the precharge and access cycles to occur simultaneously, and enabling only necessary sense amplifiers to conserve power and reduce latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If all bit lines are precharged before each access cycle, then the memory is ready for any random access, but power consumption increases and latency increases

Engineering Contradiction:
Improverandom access capabilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The memory bank is divided into multiple segments or portions, allowing selective precharging of only the specific segment that contains the target bit line, rather than precharging all bit lines in the entire bank. This segmentation enables localized operations that reduce power consumption while maintaining random access capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The precharge operation is applied locally only to the specific bit line or small group of bit lines that are about to be accessed, rather than uniformly to all bit lines. This local quality approach ensures that power and time resources are concentrated only where needed, reducing overall power consumption and latency.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If all bit lines are precharged before each access cycle, then the memory is ready for any random access, but access latency increases

Engineering Contradiction:
Improverandom access capabilityVSAvoidaccess latency
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The memory bank is divided into multiple segments or portions, allowing selective precharging of only the specific segment that contains the target bit line, rather than precharging all bit lines in the entire bank. This segmentation enables localized operations that reduce power consumption while maintaining random access capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The precharge operation is performed in advance but only on the specific bit line or small group of bit lines that are about to be accessed, rather than uniformly to all bit lines. This preliminary action ensures that the necessary bit lines are ready before access while avoiding unnecessary precharging of other bit lines, thus reducing access latency.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the entire bank is precharged before accessing a small number of bits, then all bits are accessible, but power consumption and temperature increase

Engineering Contradiction:
Improveaccess availabilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The memory bank is divided into multiple segments or portions, allowing selective precharging of only the specific segment that contains the target bit line, rather than precharging all bit lines in the entire bank. This segmentation enables localized operations that reduce power consumption while maintaining random access capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of performing a full bank precharge, only a partial precharge of the necessary bit lines or small segments is performed. This partial action is sufficient to enable the required access while avoiding the excessive power consumption and temperature increase associated with precharging the entire bank.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2038891B1Memories with selective precharge
Publication Date: 2010.08.25 S AQUA SEMICONDUCTOR LLC
  • EP2038891B1 patent drawingFigure 1(a)~1(h)
  • EP2038891B1 patent drawingFigure 2A~2C
  • EP2038891B1 patent drawingFigure 3

AI summary

Methods, apparatuses and systems of operating digital memory where the digital memory device (figure 7) including a plurality of memory cells (figure 6) receives a command to perform an operation on a subset of memory cells, where the subset of memory cells contains fewer memory cells than the device as a whole and where the device selectively precharges, in response to the received command, only a subset of bit lines associated with the subset of memory cells (figure 4).