Resistive Memory Interface Using Pre-Charged Conversion Capacitor

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Solution Overview

Problem

Resistive memory cells in micro-electronics face challenges during reading operations due to unpredictable incubation periods, leading to inefficiencies in energy consumption and potential stress on memory elements, and existing solutions do not adequately address these issues.

Innovation Solution

A memory system incorporating a conversion capacitor that applies a controlled electrical voltage to resistive memory cells, allowing for efficient reading by limiting energy transfer and independent of the selector's switching momentum, using a control module to manage the capacitor's connection and disconnection for precise energy management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a reading voltage is applied to read a memory cell, then the data stored in the cell can be accessed, but significant power consumption occurs and stress is applied to the memory element due to current flowing through the cell for the entire pulse duration

Engineering Contradiction:
Improvereading operationVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The conversion capacitor is pre-charged to a reference voltage before being connected to the memory cell. This preliminary charging action allows the capacitor to store the necessary energy for the reading operation, enabling the reading voltage to be applied without continuous power supply during the measurement process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A conversion capacitor is introduced as an intermediary element between the voltage source and the memory cell. The capacitor acts as a buffer that transfers charge to the cell during reading, decoupling the direct connection between the voltage source and the memory element, thereby reducing power consumption and stress on the memory cell.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a reading voltage pulse of long duration is applied to account for unpredictable incubation time, then the selector can become conductive, but this causes significant power consumption and stress on the memory element

Engineering Contradiction:
Improvereading operation reliabilityVSAvoidstress on memory element
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The conversion capacitor is pre-charged before the reading operation begins. This preliminary charging ensures that when the capacitor is connected to the memory cell, the voltage is already established, allowing the reading to proceed without requiring a prolonged voltage pulse that would otherwise be needed to account for incubation time variations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the temporal parameters of the reading operation by using a pre-charged capacitor instead of a continuous voltage source. This allows the reading voltage to be applied instantaneously with a well-defined start time, eliminating the need for long-duration pulses and reducing the stress on memory elements while still accommodating incubation time variations.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the reading voltage is applied immediately without waiting for incubation period, then the reading operation is faster, but the selector may not have switched to conductive state yet

Engineering Contradiction:
Improvereading speedVSAvoidreading operation success
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The conversion capacitor is pre-charged in advance before being connected to the memory cell. This preliminary action ensures that when the connection is made, the voltage is already present and stable, allowing the reading operation to start immediately without waiting for incubation periods, while still ensuring reliable operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The conversion capacitor serves as an intermediary that decouples the timing of voltage application from the switching of the selector. By using the capacitor as a buffer, the reading voltage can be applied immediately when the capacitor is connected, while the selector has sufficient time to switch to the conductive state, thus resolving the timing conflict between speed and reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces energy consumption during reading operations, minimizes stress on memory elements, and ensures consistent results regardless of the selector's switching time, thereby overcoming the inefficiencies associated with incubation phenomena.

Implementation Method 1

a conversion capacitor, a voltage measuring device connected to the terminals of the conversion capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4016531B1Memory comprising an array of resistive memories cells, and associated interface method
Publication Date: 2025.02.05 WEEBIT NANO LTD
  • EP4016531B1 patent drawingFigure 1~2
  • EP4016531B1 patent drawingFigure 3~4
  • EP4016531B1 patent drawingFigure 5~6

AI summary

The invention relates in particular to a memory (1) comprising an array (2) of resistive memory cells (20) and an interface device (3) for interfacing the array, the interface device comprising at least one conversion capacitor (4), a voltage measuring device (8) connected to the terminals of the conversion capacitor, an electrical source (7), a first switch (5) and a second switch (6), the interface device being configured to: a) connect the conversion capacitor to the source by means of the second switch to charge the conversion capacitor, then b) disconnect the conversion capacitor from the source, and connect the conversion capacitor to the array, by means of the first switch, then acquire a result reading voltage across the terminals of the conversion capacitor, by means of the voltage measuring device, then determine the resistive state of said cell by the control module,based on said reading result voltage.