FET Power Source Detection Circuit for Aircraft LRU Leakage

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Solution Overview

Problem

Existing power management systems in aircraft experience false power supply readings due to leakage current, which can lead to incorrect information for pilots and systems, affecting reliability.

Innovation Solution

The system employs field effect transistors (FETs) as high-side switches in conjunction with diodes and resistor networks to inhibit leakage current, providing accurate power source availability detection by bypassing diode leakage and offering overvoltage protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If diodes are used in OR'ed configuration for power source detection, then power source switching is enabled, but leakage current causes false power supply readings

Engineering Contradiction:

Improvepower source switching capabilityVSAvoidpower supply detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the harmful leakage current effect from the system by eliminating the diode component that causes it. The solution replaces the diode-based OR'ed configuration with a FET-based switching mechanism that does not suffer from leakage current, thereby removing the source of false power supply readings while maintaining power source switching capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces FETs as intermediary switching elements between power sources and loads. These FETs act as controlled intermediaries that can be precisely turned on or off based on power source availability, replacing the passive diode intermediary that caused measurement errors through leakage current.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If FETs are used as high-side switches with proper gate voltage control, then leakage current is inhibited and detection accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvepower source detection accuracyVSAvoidcircuit configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the FET-based power source detection unit universally compatible with multiple power source configurations (single power source, dual power sources, hot-swappable power sources). The same basic circuit topology can detect and switch between different power source arrangements, reducing the need for multiple specialized circuits and thereby managing complexity through versatility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent controls the FET switching behavior by changing the gate voltage parameter. By applying appropriate gate voltages, the FETs can be precisely controlled to turn on or off, enabling accurate power source detection and switching without the leakage current problems of diode-based systems.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple power supply sources are used for redundant architecture, then system reliability is increased, but false readings can lead to incorrect information for pilots and systems

Engineering Contradiction:

Improvesystem reliabilityVSAvoidaccuracy of power source status information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent implements feedback mechanisms where the power source detection units continuously monitor power source availability and provide accurate status information to the controller. The controller uses this feedback to make informed decisions about power source switching and to provide correct status information to pilots and systems, preventing loss of information despite the complexity of multiple power sources.

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

This solution ensures reliable power supply detection by eliminating false readings, providing internal electrostatic discharge and overvoltage protection, and reducing power consumption, thereby increasing battery lifetime.

Implementation Method 1

a first field effect transistor (FET) that is operated to inhibit leakage current flow to the first circuit

Methodology Applied

Scientific EffectField effect transistor operation: Conduction (electrical)

Implementation Method 2

coupling a controller to the first power source and the second power source using an OR'ed diode configuration

Methodology Applied

Scientific EffectDiode rectification: Diode

Data Source

PatentUS11677234B2Power input source detection in aircraft LRU

Publication Date: 2023.06.13 HAMILTON SUNDSTRAND CORP

AI summary

Provided are embodiments for a system for performing input power detection. The system includes a first input for a first power source, a second input for a second power source, and a controller that is operably coupled to the first power source and the second power source. The system also includes a first path connecting a first circuit to the first power supply, wherein the first path comprises a first field effect transistor (FET) that is operated to inhibit leakage current flow to the first circuit, and a second path connecting a second circuit to the second power supply, wherein the second path comprises a second FET that is operated to inhibit leakage current flow to the second circuit. Also provided are embodiments for a method for performing input power detection.