Nonvolatile Analog Memory Cell Stabilization

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Solution Overview

Problem

Conventional digital memories require multiple memory cells to store data, leading to increased physical dimensions and manufacturing challenges, while nonvolatile analog memories face difficulties in accurately storing and maintaining analog signals due to voltage or current drift.

Innovation Solution

A nonvolatile analog memory with a floating gate point, incorporating a first and second current source and a current adjuster, which adjusts currents to equalize them to a reference current, allowing for accurate storage of analog signals by charging and discharging a capacitor, thereby stabilizing the stored data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional digital memories are used to store data, then data can be stored reliably, but the physical dimensions and number of memory cells increase

Engineering Contradiction:

Improvedata storage reliabilityVSAvoidmemory cell area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent transitions from digital memory parameters (discrete 0/1 states) to analog memory parameters (continuous voltage or current values). By storing data as analog signals where the magnitude represents the data value, a single memory cell can store multiple bits of information, significantly reducing the number of memory cells required while maintaining data reliability through proper signal encoding and decoding mechanisms

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If nonvolatile analog memory is used to reduce memory cell area, then the number of memory cells decreases, but voltage or current drift causes data inaccuracy

Engineering Contradiction:

Improvememory cell areaVSAvoidanalog signal accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where the stored analog signal is read back and compared with reference values. Through feedback control circuits, the system can detect drift in the stored voltage or current and apply corrective adjustments to maintain the original data value, thereby ensuring measurement precision while using compact analog memory cells

Inventive Principle:

Principle #23Feedback

3Quantity of substance

If analog signals are stored in memory cells, then data capacity per cell increases, but manufacturing precision control becomes more difficult

Engineering Contradiction:

Improvedata capacity per memory cellVSAvoidmanufacturing yield control

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent employs reference voltage and reference current sources that provide standardized, stable reference levels across all memory cells. By designing the memory system to operate relative to these equipotential references rather than absolute values, variations in manufacturing parameters affect all cells uniformly, allowing for better yield control through differential measurements and compensating for manufacturing tolerances

Inventive Principle:

Principle #12Equipotentiality

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

This solution enables accurate and stable storage of data in a reduced memory cell area, ensuring data integrity and reducing the number of memory cells needed, thus addressing the challenges of conventional digital memories and analog signal accuracy.

Implementation Method 1

a capacitor, a first current source, a second current source, and a current adjuster. An end of the capacitor is coupled to the floating gate point

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The first current source is controlled by a voltage value at the floating gate point and generates a first current. The second current source generates a second current. The current adjustor receives the first current, the second current, and a reference current

Methodology Applied

Scientific EffectElectrical current: Conduction (electrical)

Data Source

PatentUS7872913B2Nonvolatile analog memory

Publication Date: 2011.01.18 NATIONAL TSING HUA UNIVERSITY

AI summary

A nonvolatile analog memory has a floating gate point. The nonvolatile analog memory includes a capacitor, a first current source, a second current source and a current adjuster. The first current source controlled by a voltage value at the floating gate point and generates a first current. The second current source controlled by the voltage value at the floating gate point and generates a second current. The current adjuster receives the output voltage and a reference voltage and adjusts the first current and the second current based on the output voltage and the reference voltage. The current adjuster charges or discharges the capacitor to equalize the output voltage to the reference voltage.