Integrated Circuit Transient Electrical Stress Protection Trigger Circuit

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Solution Overview

Problem

Integrated circuits face challenges in protecting against transient electrical stress (TES) events, particularly due to the close proximity of normal operating voltage and breakdown voltage in MOS clamping devices, which can lead to damage during TES events, especially when these events occur on the main power supply, reducing design margins and potentially causing destruction.

Innovation Solution

A trigger circuit with multiple filters coupled to different supply voltages is used to activate the clamping device, ensuring it operates effectively during TES events on both I/O pads and the main power supply, utilizing a boosted supply for the trigger circuit to provide a higher gate voltage and separate RC filters for detection, allowing for efficient current dissipation without reaching breakdown voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a MOS clamping device is used for TES protection, then current dissipation capability is improved, but the design margin between normal operating voltage and breakdown voltage becomes very tight

Engineering Contradiction:

Improvecurrent dissipation capabilityVSAvoiddesign margin

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The trigger circuit is segmented into multiple independent filters (first filter coupled to first supply voltage, second filter coupled to second supply voltage), each monitoring different voltage supplies. This segmentation allows the system to detect TES events on either supply independently and activate the clamping device appropriately, resolving the contradiction by enabling reliable detection without requiring excessive design margin.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A boosted supply is introduced as an intermediary voltage source specifically for powering the trigger circuit during TES events. This intermediary supply provides the additional gate voltage needed to activate the MOS clamping device without requiring the normal operating voltage to be close to breakdown voltage, thus maintaining design margin while enabling effective current dissipation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the trigger circuit uses a single supply voltage, then circuit complexity is reduced, but detection capability for TES events on different supplies is limited

Engineering Contradiction:

Improvetrigger circuit structureVSAvoidTES event detection capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The trigger circuit is designed with multi-functionality by incorporating filters that can detect TES events on multiple different supply voltages (first supply voltage and second supply voltage). Each filter serves a specific detection function for its associated supply, yet together they provide universal protection capability across all power supplies in the system.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the gate voltage of the MOS clamping device is increased to improve TES protection, then protection effectiveness is improved, but the risk of reaching breakdown voltage during normal operation increases

Engineering Contradiction:

ImproveTES protection effectivenessVSAvoidbreakdown risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The boosted supply is prepared in advance and coupled to the trigger circuit, ready to provide the necessary gate voltage when a TES event is detected. This preliminary preparation allows the system to quickly increase gate voltage for effective protection without requiring the gate voltage to be continuously high during normal operation, thus preventing breakdown while ensuring protection effectiveness when needed.

Inventive Principle:

Principle #10Preliminary action

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 enhances design margins for TES events on I/O pads and main power supplies, preventing damage by ensuring the clamping device operates within safe voltage limits, effectively protecting integrated circuits from both powered and unpowered transient events.

Implementation Method 1

A trigger circuit with multiple filters coupled to different supply voltages is used to activate the clamping device

Methodology Applied

Scientific EffectRC circuit transient response:

Implementation Method 2

utilizing a boosted supply for the trigger circuit to provide a higher gate voltage and separate RC filters for detection, allowing for efficient current dissipation without reaching breakdown voltage

Methodology Applied

Scientific EffectMOSFET field effect conduction:

Data Source

PatentEP3300109B1Integrated circuit with protection from transient electrical stress events and method therefor

Publication Date: 2020.12.16 NXP USA INC

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AI summary

An integrated circuit with protection against transient electrical stress events includes a trigger circuit having a first detection circuit coupled to a first supply voltage, a second detection circuit coupled to a second supply voltage, and a rail clamp device. During a first type of electrical stress event, the rail clamp device is activated in response to a first output signal provided by the first detection circuit. During a second type of electrical stress event, the rail clamp device is activated in response to a second output signal provided by the second detection circuit.