Shared TVS Protection Line for Multi-Channel SSPC Built-In Test

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Solution Overview

Problem

Existing TVS diode-based protection schemes for aircraft SSPC components require numerous individual diodes, increasing complexity and cost, and lack efficient methods for detecting dormant failures without removing modules from the aircraft, making it difficult to verify the functionality of protection circuitry.

Innovation Solution

Implementing a shared transient voltage suppressor that uses fewer TVS diodes among multiple power channels, combined with a built-in-test (BIT) circuit to efficiently and cost-effectively test for dormant failures, reducing the number of required diodes and simplifying the protection scheme.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual TVS diodes are used for every SSPC output channel, then transient protection functionality is provided, but device complexity and cost increase significantly

Engineering Contradiction:
Improvetransient protection functionalityVSAvoidnumber of TVS diodes per SSPC card
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple individual TVS diode protection circuits into a single shared TVS diode circuit that protects multiple SSPC output channels simultaneously. This consolidation reduces the number of TVS diodes from 40+ individual diodes to a single shared diode, thereby reducing device complexity and cost while maintaining transient protection functionality across all channels.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared TVS diode circuit is designed to provide universal transient protection across multiple different output channels of the SSPC. A single TVS diode circuit serves the function of multiple individual protection circuits, making the protection system more versatile and reducing overall component count while maintaining comprehensive coverage for lightning-induced transients on various channels.

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

2Reliability

If individual TVS diodes are used for every channel, then protection coverage is complete, but cost and manufacturing complexity increase

Engineering Contradiction:
Improveprotection coverageVSAvoidcost and complexity of protection circuitry
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple individual protection circuits into a single shared TVS diode circuit, reducing the bill of materials cost and simplifying manufacturing processes. Instead of sourcing, stocking, and assembling 40+ individual TVS diodes, the system uses a single shared diode, thereby improving ease of manufacture and reducing overall system cost while maintaining complete protection coverage across all channels.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If BIT circuitry is added to test each TVS diode for dormant failures, then failure detection capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefailure detection capabilityVSAvoidcomplexity of BIT circuitry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the BIT testing functionality into a single shared test circuit that can test the shared TVS diode circuit. Instead of requiring individual BIT circuits for each TVS diode, the shared architecture allows one test circuit to verify the functionality of the shared protection circuit, thereby reducing BIT circuitry complexity while maintaining dormant failure detection capability.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If module removal from aircraft is required for protection verification, then accurate testing can be performed, but operational time and aircraft availability are reduced

Engineering Contradiction:
Improvetesting accuracyVSAvoidaircraft availability
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements a self-testing capability through the shared BIT circuit that allows the SSPC module to verify its own protection circuitry functionality while installed in the aircraft. The BIT circuit can activate the shared TVS diode circuit and monitor its response, enabling in-situ verification of transient protection without requiring module removal, thereby maintaining aircraft availability while ensuring protection integrity.

Inventive Principle:
Principle #25Self-service

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 approach significantly reduces the number of diodes needed, making the protection scheme more efficient and cost-effective while enabling effective detection of dormant failures without removing modules from the aircraft, thereby enhancing the reliability of SSPC components.

Implementation Method 1

TVS diodes provide protection to MOSFETs by shunting excess current when the lightning-induced voltage exceeds the diode avalanche breakdown potential. TVS diodes are, in effect, clamping devices that suppress all voltages above their breakdown voltages

Methodology Applied
Scientific EffectAvalanche breakdown: Avalanche Breakdown

Data Source

PatentEP3203251B1Shared transient voltage suppressor for protecting multiple load channels of a solid state power controller having built-in-test capability
Publication Date: 2024.09.11 HAMILTON SUNDSTRAND CORP
  • EP3203251B1 patent drawingFigure 1
  • EP3203251B1 patent drawingFigure 2
  • EP3203251B1 patent drawingFigure 3

AI summary

Embodiments are directed to a transient protection circuit configured for use in a SSPC having a plurality of power channels. The transient protection circuit includes a shared transient voltage suppressor, and a shared protection line communicatively coupled to the shared transient voltage suppressor (360). The shared protection line (358) is configured to be communicatively coupled to and shared by the plurality of power channels. When the shared protection line is communicatively coupled to and shared by the plurality of power channels, energy above a threshold on any one of the plurality of power channels is dissipated through the shared protection line and the shared transient voltage suppressor.