Two-Wire Power and Serial Link for Intrinsically Safe Avionics

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Solution Overview

Problem

Avionics systems face challenges with increased weight, complexity, and cost due to multiple wires for power and data communication, which also compromise reliability and safety in flammable environments.

Innovation Solution

A two-wire power and serial communication system using a resistor network, current limiters, and voltage regulators to transmit power and data, ensuring intrinsic safety and fault tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple wires are used for power and data communication, then power and data can be transmitted reliably, but weight and complexity increase

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidwire weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines power transmission and data communication into a single two-wire interface. The same pair of wires used for serial communication also carries power signals, eliminating the need for separate power wiring. This merging of functions directly reduces wire weight while maintaining reliable power and data transmission through the shared medium.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple wires are used for power and data communication, then power and data can be transmitted reliably, but device complexity increases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidwiring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system merges power delivery and serial communication into a single two-wire interface, eliminating separate power connections and reducing wiring complexity. The same wires carry both data signals and power, simplifying the overall system architecture and reducing the number of connectors and wiring harnesses required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The two-wire interface serves multiple functions simultaneously: it provides bidirectional serial communication and bidirectional power transmission. This multi-functionality eliminates the need for dedicated power wires and simplifies the system design, making the same infrastructure serve both data and power needs.

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

3Reliability

If conventional power conditioning is used, then power bus variation is corrected, but switched mode power supply adds weight and complexity

Engineering Contradiction:
Improvepower conditioningVSAvoidpower supply weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The remote device performs its own power regulation and conditioning functions using local circuitry. Instead of relying on heavy external switched-mode power supplies, each device self-regulates the power it receives, converting and conditioning power locally to adapt to bus variations. This eliminates the need for heavy external power conditioning equipment.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If active sensors are placed in flammable environment, then sensing capability is improved, but intrinsic safety requirements increase cost

Engineering Contradiction:
Improvesensing capabilityVSAvoidintrinsic safety complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system changes the electrical parameters of the communication interface to intrinsically safe levels. By operating at low voltage and current thresholds that cannot cause ignition in flammable environments, the system enables active sensors to be deployed in hazardous areas without requiring complex safety certification or additional safety equipment.

Inventive Principle:
Principle #35Parameter changes

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

The system reduces weight, complexity, and cost while enhancing reliability and safety in flammable environments by utilizing a two-wire configuration with resistor networks and current/voltage limiters.

Implementation Method 1

powering a voltage regulator using a steering diode and forward biasing the steering diode

Methodology Applied
Scientific EffectForward biasing: Diode

Implementation Method 2

powering a hold up capacitor using the received power signal

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

monitoring by the in board computer a voltage drop across the resistor network

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3849134B1Power and serial communication scheme
Publication Date: 2026.03.11 SIMMONDS PRECISION PRODUCTS INC
  • EP3849134B1 patent drawingFigure 1
  • EP3849134B1 patent drawingFigure 2
  • EP3849134B1 patent drawingFigure 3

AI summary

A power and data communication system including an inboard computer system that includes a resistor network, an outboard computer system that includes at least one current limiter and voltage limiter that receives power from the inboard computer in order to power electronics of the outboard computer, and first and second wires connecting the resistor network to the at least one current limiter.