Configurable IC Protection Circuit for Transient Signal Handling

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Solution Overview

Problem

Electronic systems face damage from transient signal events like electrostatic discharge due to overvoltage and high power dissipation, which can cause gate oxide punch-through, junction damage, and latch-up, necessitating effective protection mechanisms.

Innovation Solution

A configurable protection circuit within an integrated circuit (IC) comprising a plurality of subcircuits arranged in a cascade, where the selection of subcircuits determines the holding and trigger voltages, providing adaptive protection against transient signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protection circuit is designed to withstand high voltage transient events, then the holding voltage must be increased, but this increases the trigger voltage as well, which may prevent normal operation at lower voltages

Engineering Contradiction:
Improveprotection capabilityVSAvoidvoltage range compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The circuit dynamically switches between different protection modes by activating or deactivating specific transistors (Q1-Q4) and protection paths based on the applied voltage level. This allows the holding and trigger voltages to be adjusted in real-time, enabling the same circuit to protect against both low-voltage and high-voltage transient events without compromising normal operation at different voltage levels.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The circuit changes its electrical parameters (holding voltage and trigger voltage) by selectively activating different protection subcircuits. Through control logic that monitors voltage levels, the circuit modifies its protection characteristics to match the operating conditions, thereby achieving both high protection capability and adaptability to different voltage ranges.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple protection subcircuits are integrated into a single IC, then the circuit area increases, but the manufacturing complexity and cost also increase

Engineering Contradiction:
Improveprotection functionalityVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple protection subcircuits (including ESD protection, overvoltage protection, and clamping circuits) into a single integrated protection unit that shares common components such as transistors, diodes, and control logic. This merging approach reduces the total circuit area and simplifies manufacturing while maintaining comprehensive protection functionality across different voltage levels and transient event types.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protection circuit is designed as a universal module that can handle multiple types of transient events (ESD, surge, voltage spikes) and operate across different voltage domains. By creating a multi-functional protection unit with configurable holding and trigger voltages, the circuit reduces overall system complexity compared to having separate dedicated protection circuits for each function and voltage level.

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

3Object-affected harmful factors

If the holding voltage is set high to protect against severe transient events, then the trigger voltage also increases, which may interfere with normal circuit operation at lower voltages

Engineering Contradiction:
Improvetransient event protectionVSAvoidnormal operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The circuit employs dynamic voltage threshold adjustment by selectively activating different protection paths based on the detected voltage level. During normal low-voltage operation, the high-threshold protection path remains inactive, allowing uninterrupted operation. When a transient event exceeds the normal operating voltage, the circuit dynamically activates the appropriate protection subcircuit with matching holding and trigger voltages, thereby protecting against harmful transients without interfering with normal operation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3336896B1Apparatus and method for electronic systems reliability
Publication Date: 2019.09.18 ANALOG DEVICES INC
  • EP3336896B1 patent drawingFigure 1
  • EP3336896B1 patent drawingFigure 2
  • EP3336896B1 patent drawingFigure 3A~3B

AI summary

Apparatus and methods for protecting electronic circuits are disclosed. In one embodiment, an apparatus for providing protection from transient signals (14, 16) comprises an integrated circuit (1), a pad (42) on a surface of the integrated circuit, and a configurable protection circuit (22) within the integrated circuit. The configurable protection circuit is electrically connected to the pad. The configurable protection circuit comprises a plurality of subcircuits (72, 74, 76) arranged in a cascade, and selection of one or more of the plurality of the subcircuits for operation determines at least one of a holding voltage or a trigger voltage of the configurable protection circuit.