ESD Protection Circuit Using Clock-Duration Signal Filtering

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Solution Overview

Problem

Electronic devices are vulnerable to electromagnetic perturbations such as electrostatic discharge (ESD), which can cause malfunctions and require robust protection mechanisms to ensure continuous operation.

Innovation Solution

An electronic device comprising detection units for generating a detection signal in response to ESD, a protection unit that generates an error signal only if the detection signal exceeds a predefined fraction of the clock period, and filtering components to prevent false error signals from short ESD perturbations, ensuring the circuit remains operational by ignoring very short ESD events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the protection unit responds to all detection signals immediately, then rapid protection is achieved, but the circuit may reset or malfunction due to transient ESD perturbations being misinterpreted as genuine errors

Engineering Contradiction:
Improveresponse speed to ESDVSAvoidcircuit stability during ESD
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The protection unit employs dynamic signal evaluation by measuring the duration of detection signals and comparing them against a time threshold. This dynamic approach enables the system to maintain rapid response capability for genuine errors while automatically filtering transient perturbations, thus preserving both speed and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention introduces an intermediary time-duration comparison mechanism between the detection units and the error signal generation. This intermediary layer acts as a filter that mediates between rapid detection and reliable response, preventing transient signals from triggering false protection actions while maintaining rapid response to genuine threats.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If filtering components are added to prevent false error signals, then circuit stability is improved, but the device complexity increases

Engineering Contradiction:
Improvecircuit stability during ESDVSAvoidprotection circuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the filtering function directly into the existing protection unit logic by comparing detection signal duration against a clock-derived threshold. This integration approach combines protection and filtering functions in a single unit, achieving enhanced reliability without proportionally increasing device complexity through separate filtering components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protection unit is designed with multi-functionality, serving both as an error detection mechanism and as a filter for transient perturbations. By making the protection unit universal in its function, the invention avoids adding dedicated filtering hardware, thus improving reliability while minimizing the increase in device complexity.

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

Data Source

PatentEP2842228B1Electronic device and method for maintaining functionality of an integrated circuit during electrical aggressions
Publication Date: 2020.02.26 NXP USA INC
  • EP2842228B1 patent drawingFigure 1
  • EP2842228B1 patent drawingFigure 2
  • EP2842228B1 patent drawingFigure 3(A)~3(D)

AI summary

An electronic device (10) for generating an error signal in response to an electrostatic discharge perturbation is described. The device (10) may comprise: a detection unit (34; 36; 38) for generating a detection signal in response to said electrostatic discharge perturbation, said detection signal correlating in time with said electrostatic discharge perturbation; a clock (26) for generating a clock signal having a clock period; and a protection unit (28) for generating an error signal in response to said detection signal only when a duration of said detection signal exceeds a predefined multiple of said clock period. A method of generating an error signal in response to an electrostatic discharge perturbation, for protecting electronic circuitry, is also disclosed.