Fail-Safe Link With Parallel Solid State Switches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solid state power controllers (SSPCs) lack effective failsafe protection mechanisms, particularly for shorted Field Effect Transistors (FETs), which can lead to wire integration issues and safety threats, and rely on physical fusing devices that limit programmability and wire weight savings.
Innovation Solution
A fail-safe link design utilizing multiple branches of solid state switches with varying periphery sizes in parallel and series configurations, combined with a built-in test circuit that senses overvoltage conditions and controls the switches to prevent short circuits, allowing the circuit to function even with a shorted FET and reporting failures for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical fusing devices are used for failsafe protection, then wire separation relief is achieved, but wire integration flexibility is limited and wire weight savings are reduced
Solution Approach 1:
The patent replaces physical fusing devices (mechanical/thermal protection) with solid state switches and control circuitry (electronic protection). The solid state power controller uses electronic switching elements and control logic to provide failsafe protection, eliminating the need for physical fuses and thereby enabling flexible wire integration and connector selection without thermal rating constraints.
2Device complexity
If solid state switches are used without backup protection, then device complexity is reduced, but reliability on fault conditions deteriorates
Solution Approach 1:
The patent implements a control circuit that continuously monitors the state of solid state switches and provides feedback control. The controller detects fault conditions (such as shorted FETs) and responds by activating backup protection mechanisms or isolating failed components. This feedback-based approach enables the system to maintain reliability without requiring complex permanent backup structures, as protection is activated only when needed.
3Ease of manufacture
If single-thermal-rating fuses are used, then manufacturing simplicity is maintained, but programmability and variable thermal management are limited
Solution Approach 1:
The patent replaces static, fixed-thermal-rating fuses with dynamic solid state switches that can be programmably configured. The solid state power controller allows variable thermal management by adjusting switching parameters, current limits, and protection thresholds through software programming. This dynamic approach maintains manufacturing simplicity while enabling adaptability, as the same hardware platform can be programmed for different thermal ratings and protection schemes.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present disclosure is directed to a fail-safe link with a branch comprising a plurality of solid state switches of varying periphery sizes connected in series between a power source and a load. A built-in test circuit senses an overvoltage condition across one or more of the switches of varying periphery sizes and opens or closes the one or more of the switches of varying periphery sizes in accordance with a measured voltage across at least one solid state switch of the plurality of solid state switches. In an arrangement comprising a plurality of branches, the test circuit is connected with the supply side switches and the load switches of the plurality of branches and provides an indication whether a failure has occurred in the supply side switches or the load side switches.