Saturation Region Sense Amplifier for Flash Memory Sensing Accuracy

Solution Overview

Problem

Advanced manufacturing techniques in flash memory reduce sensing current, leading to smaller sensing margins and increased errors in data sensing accuracy for conventional sense amplifiers.

Innovation Solution

A sense amplifier design that includes a sensing node, a reference node, bias circuits, transmission circuits, and a latch circuit, where the nodes are biased to specific voltages and discharged through memory cells, with the latch circuit amplifying the voltage difference to enhance data sensing accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If sensing current is reduced to lower power consumption and increase access speed, then power consumption decreases and access speed increases, but sensing margin becomes smaller and data sensing accuracy deteriorates

Engineering Contradiction:

Improveaccess speedVSAvoiddata sensing accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent changes the operating parameters of the transmission transistors by biasing them in the saturation region rather than the linear region. This parameter change allows the transistors to provide stable current drive while maintaining high sensing accuracy, resolving the contradiction between speed and accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The latch circuit in the sense amplifier provides feedback to amplify and stabilize the voltage difference between sensing and reference nodes. This feedback mechanism ensures that even with reduced sensing current, the voltage difference is sufficiently amplified to maintain high data sensing accuracy

Inventive Principle:

Principle #23Feedback

2Use of energy by moving object

If sensing current is reduced to lower power consumption, then power consumption decreases, but sensing margin becomes smaller and data sensing accuracy deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoiddata sensing accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent changes the operating parameters of the transmission transistors by biasing them in the saturation region rather than the linear region. This parameter change allows the transistors to provide stable current drive while maintaining high sensing accuracy, resolving the contradiction between speed and accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The latch circuit in the sense amplifier provides feedback to amplify and stabilize the voltage difference between sensing and reference nodes. This feedback mechanism ensures that even with reduced sensing current, the voltage difference is sufficiently amplified to maintain high data sensing accuracy

Inventive Principle:

Principle #23Feedback

3Use of energy by moving object

If conventional sense amplifier is used with reduced sensing current, then power consumption is lowered, but voltage deviation becomes unstable and sensing errors increase

Engineering Contradiction:

Improvepower consumptionVSAvoidvoltage stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The latch circuit provides feedback to continuously monitor and stabilize the voltage difference between sensing and reference nodes. This feedback mechanism compensates for voltage deviations caused by reduced sensing current, maintaining voltage stability and preventing sensing errors

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The bias circuits are designed to provide sufficient bias current to the transmission transistors before the sensing operation begins. This beforehand cushioning ensures that the transistors operate in the saturation region with stable current drive, preventing voltage deviations during the sensing process

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS8238184B2Sense amplifier with a sensing transmission transistor and a reference transmission transistor operating in saturation regions and data sensing method thereof

Publication Date: 2012.08.07 MACRONIX INTERNATIONAL CO LTD

AI summary

A data sensing method for sensing storage data stored in a memory cell includes the steps of: biasing a sensing node and a reference node to a first voltage in response to a first control signal; discharging the sensing node and the reference node via the memory cell and a reference memory cell, respectively; enabling a latch circuit to amplify a voltage difference between the sensing node and the reference node.