Two-Wire Load Control via Phase-Control Timing Signals

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Solution Overview

Problem

Existing load control systems for fluorescent lamps require additional wiring and complex commissioning processes to upgrade from non-dimming to dimming systems, and existing power-line carrier communication systems suffer from noise interference and reliability issues.

Innovation Solution

A two-wire load control system that uses a controller to generate a phase-control voltage with variable timing edges for digital communication, allowing power and control signals to be transmitted over existing wiring without needing a neutral connection, and enables soft addressing and configuration without additional wiring or complex procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional wiring is installed to upgrade from non-dimming to dimming systems, then lighting control functionality is improved, but installation cost and complexity increase

Engineering Contradiction:

Improvelighting control functionalityVSAvoidinstallation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines power transmission and control signal transmission into a single two-wire system. The controller generates a phase-control voltage that carries both power to the ballast and control signals for dimming functionality, eliminating the need for separate control wiring and simplifying installation while maintaining full dimming capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The existing power wiring is made multi-functional by using it to carry both power delivery and control communication. The phase-control voltage serves dual purposes: providing necessary power to the ballast and encoding control information through timing edges, thereby upgrading non-dimming systems to dimming systems without additional wiring

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If power-line carrier communication is used for control signals, then communication over existing wiring is achieved, but noise interference and reliability issues worsen

Engineering Contradiction:

Improvecommunication over existing wiringVSAvoidsignal reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces traditional power-line carrier communication (which modulates high-frequency signals onto power lines) with a phase-control voltage system that uses timing edges of the power waveform itself to encode control signals. This substitution avoids the noise and interference problems of PLC by using the inherent structure of the power waveform rather than superimposing communication signals on top of it

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The phase-control voltage acts as an intermediary that carries control information through timing variations rather than through separate communication signals. By encoding control data in the timing edges of the power waveform, the system achieves reliable communication without the interference issues of traditional PLC methods

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If neutral connection is required for control systems, then reliable reference voltage is provided, but installation requirements and cost increase

Engineering Contradiction:

Improvereference voltage stabilityVSAvoidinstallation ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The system serves itself by using the hot wire from the AC power source as the reference for generating the phase-control voltage. The controller derives its timing reference directly from the incoming AC waveform without needing a neutral connection, enabling installation in locations where neutral access is unavailable and simplifying wiring requirements

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

Enables reliable, cost-effective control of multiple lighting fixtures independently, reduces installation costs and complexity, and minimizes interference with other devices on the electrical network.

Implementation Method 1

A two-wire load control system having a controller that generates a phase-control voltage with variable timing edges for digital communication

Methodology Applied

Scientific EffectPhase control:

Data Source

PatentUS12490365B2Digital load control system providing power and communication via existing power wiring

Publication Date: 2025.12.02 LUTRON TECHNOLOGY COMPANY LLC

AI summary

A two-way load control system comprises a power device, such as a load control device for controlling an electrical load receiving power from an AC power source, and a controller adapted to be coupled in series between the source and the power device. The load control system may be installed without requiring any additional wires to be run, and is easily configured without the need for a computer or an advanced commissioning procedure. The power device receives both power and communication over two wires. The controller generates a phase-control voltage and transmits a forward digital message to the power device by encoding digital information in timing edges of the phase-control voltage. The power device transmits a reverse digital message to the controller via the power wiring.