Reprogrammable E-Fuse System Using Dual Strings and Voltage Comparison

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Solution Overview

Problem

Conventional electronic fuse (e-fuse) systems are limited to one-time programmability, making it difficult to achieve repeatable circuit and code configuration in applications that require multiple programming capabilities.

Innovation Solution

A reprogrammable e-fuse system is designed with a pair of e-fuse strings and a selector/comparator configuration, allowing alternation between the e-fuse strings for programming, enabling multiple reprogramming by comparing voltage across the strings to determine the programming state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional e-fuse technology is used, then the e-fuse can be programmed once, but it cannot be reprogrammed after blowing

Engineering Contradiction:

ImprovereprogrammabilityVSAvoidfuse structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The fuse structure is divided into two separate strings (first e-fuse string and second e-fuse string) with identical configurations. This segmentation allows one string to be programmed while the other remains available for future reprogramming operations, enabling multi-time programmability without increasing the complexity of individual fuse elements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Two e-fuse strings are combined into a single reprogrammable e-fuse system with shared control circuitry. The selector circuit and comparator are shared resources that manage both strings, allowing the system to achieve reprogrammability while minimizing the increase in overall device complexity through resource sharing.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If anti-fuse components are incorporated on the same chip for reprogramming, then reprogramming capability is achieved, but two different programming technologies with extra fabrication steps are required

Engineering Contradiction:

Improvereprogramming capabilityVSAvoidfabrication process

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The same programming mechanism is designed to serve multiple programming operations across different time periods. The programming circuitry and methodology are made universal so that the identical process can program both the first and second e-fuse strings, eliminating the need for separate anti-fuse fabrication steps and simplifying the manufacturing process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a single e-fuse string is used, then the structure is simple, but only one-time programmability is permitted

Engineering Contradiction:

Improveprogramming timesVSAvoidnumber of e-fuse strings

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system dynamically switches between the first and second e-fuse strings based on programming state and timing. The selector circuit provides dynamic control, enabling the system to adapt its configuration over time - using one string initially and transitioning to the other string for reprogramming operations, thereby achieving multiple programming times with minimal structural complexity.

Inventive Principle:

Principle #15Dynamics

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 allows for multiple reprogramming cycles while maintaining controlled resistance ratios, enabling the e-fuse system to remember its state and facilitating repeatable circuit configuration without physical rupture of the fuse link.

Implementation Method 1

comparator connected to both the first e-fuse string and the second e-fuse string configured to compare a voltage across the first e-fuse string to a voltage across the second e-fuse string

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

When the pair of e-fuses is to be programmed, a first programming current is applied to a first e-fuse to increase the resistance of the first e-fuse by an incremental amount

Methodology Applied

Scientific EffectElectromigration:

Data Source

PatentUS8189419B2Apparatus for nonvolatile multi-programmable electronic fuse system

Publication Date: 2012.05.29 MARVELL ASIA PTE LTD

AI summary

Electronic fuse (e-fuse) systems with multiple reprogrammability are provided. In one aspect, a reprogrammable e-fuse system is provided that includes a first e-fuse string; a second e-fuse string; a selector connected to both the first e-fuse string and the second e-fuse string configured to alternately select an e-fuse from the first e-fuse string or the second e-fuse string to be programmed; and a comparator connected to both the first e-fuse string and the second e-fuse string configured to compare a voltage across the first e-fuse string to a voltage across the second e-fuse string to determine a programming state of the e-fuse system.