Current Driving Circuit for Non-Volatile Memory Cells

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Solution Overview

Problem

Current memory designs face challenges in providing sufficient driving capability without increasing circuit size, especially when the circuit area is reduced, leading to insufficient access to memory units.

Innovation Solution

A memory structure incorporating (n-1) non-volatile cells and a current driving circuit with n transistors, where each non-volatile cell has a first and second terminal, and bit lines are coupled to these cells, forming a 3T2M or nT(n-1)M structure that improves driving capability and maintains a smaller circuit area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the circuit area is reduced, then the memory size is smaller, but the driving current becomes insufficient

Engineering Contradiction:
Improvecircuit areaVSAvoiddriving current
Core Design Contradiction:
Area of stationary objectVSPower

Solution Approach 1:

The patent merges multiple transistor functions into a shared current driving circuit. The first and second transistors share a common drain electrode connected to the bit line, and the third transistor shares the bit line connection. This merging allows the circuit to achieve sufficient driving current capability while occupying reduced circuit area, as the shared components provide cumulative driving capability without requiring separate dedicated transistors for each function.

Inventive Principle:
Principle #5Merging (Combining)

2Power

If the number of transistors in driving circuit is increased to improve driving capability, then the driving current is sufficient, but the circuit size increases and simplification becomes difficult

Engineering Contradiction:
Improvedriving currentVSAvoidcircuit complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent combines multiple transistor operations into a unified current driving circuit with shared components. The first, second, and third transistors share the bit line connection and are controlled through coordinated gating, reducing the total component count while maintaining sufficient driving capability. This merging approach simplifies the circuit structure compared to having separate dedicated transistors for each cell access operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The current driving circuit is designed with multi-functionality, where the shared transistors and bit line connections serve multiple purposes. The same transistor components can drive current for different non-volatile cells through selective gating, and the bit line serves as both a signal line and a current path for multiple cells. This universality reduces overall circuit complexity while providing adequate driving capability for all cell access operations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3848932A1Memory including non-volatile cells and current driving circuit
Publication Date: 2021.07.14 UNITED MICROELECTRONICS CORP
  • EP3848932A1 patent drawingFigure 1~2
  • EP3848932A1 patent drawingFigure 3~4
  • EP3848932A1 patent drawingFigure 5

AI summary

A memory includes (n-1) non-volatile cells, (n-1) bit lines and a current driving circuit. Each of the (n-1) non-volatile cells includes a first terminal and a second terminal. An ith bit line of the (n-1) bit lines is coupled to a first terminal of an ith non-volatile cell of the (n-1) non-volatile cells. The current driving circuit includes n first transistors coupled to the (n-1) non-volatile cells.