Fuse Circuit Inrush Current Control via Preliminary Detection

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Solution Overview

Problem

Inrush currents generated during the power-up period in semiconductor devices with fuse circuits can destabilize the internal power voltage generator, particularly in mobile DRAMs, leading to reliability issues due to excessive current load.

Innovation Solution

A fuse circuit design that includes a fuse section and a current path break section, where the current path break section detects the fuse status before the power-up signal trip period and breaks the inrush current path using a second N-type MOS transistor, reducing the inrush current by maintaining the N-type MOS transistor NM2b off during the trip period.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fuse circuit is used in a semiconductor device, then redundancy function is provided, but inrush current is generated during power-up period

Engineering Contradiction:

Improveredundancy functionVSAvoidinrush current

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by detecting the fuse status before the power-up signal transitions (at the trip point) and pre-configuring the current path break section accordingly. The second N-type MOS transistor (NM2b) is turned off in advance based on the detected fuse status, preventing the inrush current path from forming when the power-up signal transitions and simultaneously enabling the latch circuit to capture the correct fuse status.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the number of fuse circuits is increased, then redundancy coverage is improved, but inrush current amount increases

Engineering Contradiction:

Improveredundancy coverageVSAvoidinrush current amount

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

By detecting fuse status at the trip point before power-up transition and pre-configuring the current path break section, the patent prevents inrush current in each fuse circuit. This per-circuit prevention approach scales effectively, allowing multiple fuse circuits to be implemented without proportionally increasing total inrush current, thereby improving redundancy coverage while controlling inrush current magnitude.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If inrush current is generated during power-up period, then fuse circuit operation is simplified, but power supply stability deteriorates

Engineering Contradiction:

Improvefuse circuit operationVSAvoidpower supply stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent introduces an intermediary detection mechanism (second N-type MOS transistor NM2b and current path break section) that mediates between the fuse circuit operation and power supply stability. This intermediary detects fuse status and controls the current path to prevent inrush current, thereby maintaining power supply stability without complicating fuse circuit operation, as the detection and control are automatically integrated into the power-up sequence.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7940116B2Fuse circuit and semiconductor device including the same

Publication Date: 2011.05.10 SAMSUNG ELECTRONICS CO LTD

AI summary

A fuse circuit may include a fuse section which generates a fuse control signal at an output terminal of the fuse circuit in response to a power-up signal according to a status of a fuse in the fuse section; and a current path break section which detects the status of the fuse in the fuse section prior to a trip period of the power-up signal and breaks an inrush current path created in the fuse section during the trip period based on the detected status.