Shared TVS Protection Circuit With BIT for Multi-Channel SSPCs

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Solution Overview

Problem

Existing SSPC protection schemes require individual TVS diodes for each power channel, leading to increased complexity, cost, and difficulty in detecting dormant failures without extensive BIT circuitry, which is costly and space-prohibitive.

Innovation Solution

Implementing a shared transient voltage suppressor and transient isolator circuit that uses a single or fewer TVS diodes per multiple power channels, coupled with a cost-effective BIT circuit to test for dormant failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual TVS diodes are used for each power channel, then protection reliability is improved, but device complexity and cost increase

Engineering Contradiction:

Improveprotection reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple TVS diodes into a single shared transient voltage suppressor that protects multiple power channels simultaneously. This consolidation reduces the total number of TVS diodes from one per channel to a single shared device, thereby reducing device complexity while maintaining protection coverage across all channels through a common suppression mechanism.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared transient voltage suppressor is designed to perform multiple protection functions across different power channels simultaneously. This single device provides universal protection capability for all channels, eliminating the need for dedicated TVS diodes on each channel and reducing overall system complexity while preserving reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If individual TVS diodes are used for each power channel, then protection coverage is improved, but cost increases

Engineering Contradiction:

Improveprotection coverageVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple individual TVS diodes into a single shared transient voltage suppressor unit. This merging reduces the component count and associated costs while maintaining comprehensive protection coverage across all power channels through the shared suppressor's ability to handle transient voltages for multiple channels simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

3Difficulty of detecting and measuring

If extensive BIT circuitry is added to test TVS diodes, then detection capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedetection capabilityVSAvoiddevice complexity

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent merges the test functions for multiple TVS diodes into a single integrated BIT circuit that can test the shared transient voltage suppressor. This consolidated approach reduces the amount of BIT circuitry needed compared to testing individual diodes separately, thereby improving detection capability while minimizing the increase in device complexity.

Inventive Principle:

Principle #5Merging (Combining)

4Device complexity

If a shared transient voltage suppressor is used, then device complexity is reduced, but detection of dormant failures becomes more difficult

Engineering Contradiction:

Improvedevice complexityVSAvoiddetection of dormant failures

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent incorporates a built-in test (BIT) circuit that provides feedback functionality to detect dormant failures in the shared transient voltage suppressor. This feedback mechanism enables the system to monitor the health status of the shared suppressor and identify failures, compensating for the increased detection difficulty introduced by using a shared configuration.

Inventive Principle:

Principle #23Feedback

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

Reduces the number of TVS diodes needed, making it efficient and cost-effective to provide protection from lightning-induced transients while enabling effective detection of dormant failures.

Implementation Method 1

TVS diodes provide protection to MOSFETs by shunting excess current when the lightning-induced voltage exceeds the TVS 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

PatentEP3176895B1Shared transient voltage suppressor having built-in-test capability for solid state power controllers

Publication Date: 2025.10.22 HAMILTON SUNDSTRAND CORP

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AI summary

Embodiments are directed to a lightning protection circuit configured for use in a solid state power controller (SSPC) having at least one feed line and a plurality of load lines. The lightning protection circuit includes a shared transient voltage suppressor (160) and a transient isolator (140) communicatively coupled to the shared transient voltage suppressor. The transient isolator is configured to be communicatively coupled to the at least one feed line and the plurality of load lines. When the transient isolator is communicatively coupled to and shared by the at least one feed line and the plurality of load lines, energy above a threshold on any one of the at least one feed line and the plurality of load lines is dissipated through the shared transient voltage suppressor. A single built-in-test (BIT) circuit (162) is provided to detect dormant failures of the shared transient voltage suppressor.