Memory Sensing Circuit Compensation Source Read Cycle

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Solution Overview

Problem

Existing sensing circuits for non-volatile memory devices face challenges in accurately determining the storing states of cells, particularly when the cell current magnitudes in the 'on' and 'off' states do not differ significantly, leading to potential erroneous detection.

Innovation Solution

Incorporating a compensation source that provides a compensating current during the read cycle to differentiate between the 'on' and 'off' states by adjusting the voltage dynamics at the sensing node, ensuring correct state detection even when the current differences are minimal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional sensing circuit is used to detect cell states, then the circuit structure remains simple, but the detection accuracy deteriorates when cell current magnitudes in 'on' and 'off' states do not differ significantly

Engineering Contradiction:

Improvedetection accuracyVSAvoidcircuit structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

A compensation current source is introduced as an intermediary element to provide a reference current that compensates for the threshold voltage effects and other non-ideal behaviors in the sensing circuit. This compensation current acts as a mediator between the cell current and the decision threshold, enabling accurate detection even when current magnitudes are similar. The compensation current source includes control circuitry that adjusts the compensation current based on detected voltage levels, ensuring reliable state differentiation without requiring complex circuit restructuring.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the cell current difference between 'on' and 'off' states is small, then the memory device operates with lower power consumption, but the detection reliability deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoiddetection reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The sensing circuit dynamically adjusts the compensation current parameter based on the detected voltage level at the sensing node. When the voltage indicates an 'on' state, the compensation current is set to a first level; when the voltage indicates an 'off' state, the compensation current is set to a second level. This parameter adjustment enables the circuit to maintain high detection reliability across different operating conditions while preserving the low power consumption advantage of small current differences between states.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If no compensation current is provided, then the sensing circuit operates with lower complexity, but erroneous detection occurs when current differences are minimal

Engineering Contradiction:

Improvesensing circuit complexityVSAvoidstate determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The compensation current is provided in advance during a determination phase before the final state decision is made. The control circuitry first detects the voltage level at the sensing node, then adjusts the compensation current accordingly, and only then makes the final state determination. This preliminary action of adjusting the compensation current based on initial voltage detection prevents erroneous readings and ensures accurate state determination while maintaining relatively simple circuit architecture.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively prevents erroneous detection by providing a compensating current that distinguishes between the 'on' and 'off' states, ensuring accurate determination of cell states, even when current differences are less than one order of magnitude, thereby enhancing the reliability of read cycles.

Implementation Method 1

a compensation source capable of providing a compensating current to a first node during a read cycle

Methodology Applied

Scientific EffectElectrical current: Conduction (electrical)

Implementation Method 2

The cell is capable of generating a cell current during the read cycle

Methodology Applied

Scientific EffectElectrical current: Conduction (electrical)

Implementation Method 3

the sensing module determines that the cell is in a first storing state or a second storing state in response to a relationship between the compensating current and the cell current

Methodology Applied

Scientific EffectVoltage detection: Electric Field

Data Source

PatentUS11217316B2Sensing circuit of memory device and associated sensing method

Publication Date: 2022.01.04 MACRONIX INTERNATIONAL CO LTD

AI summary

A sensing circuit, a sensing method and a memory device are provided. The sensing method is applied to the memory device having the sensing circuit. The sensing circuit includes a compensation source and a sensing module. The compensation source is capable of providing a compensating current to a first node during a read cycle. The sensing module is coupled to the first node. A cell of the memory device is coupled to the first node. The cell is capable of generating a cell current during the read cycle, and the sensing module determines that the cell is in a first storing state or a second storing state in response to a relationship between the compensating current and the cell current.