Solid-State Light Dimming via Phase-Cut and PWM Hybrid Control

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Solution Overview

Problem

Existing phase-cut dimming devices are incompatible with modern smart solid-state lighting technologies, leading to erratic flickering and performance issues, and removing legacy dimming elements from existing infrastructure is costly and laborious, while smart PWM dimming devices are often not compatible with phase-cut dimmers, causing user frustration.

Innovation Solution

A system combining phase-cut dimming and high-frequency PWM dimming, using a digital rectification module and microcontroller unit (MCU) to generate a rectified DC power and PWM signals, which are then processed by a DC-to-DC converter to achieve stable dimming of solid-state emitters, allowing compatibility with both legacy and smart lighting systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If phase-cut dimming is used to control solid-state lighting, then compatibility with legacy lighting infrastructure is improved, but erratic flickering and performance issues occur

Engineering Contradiction:
Improvecompatibility with legacy dimming infrastructureVSAvoidlight output stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediary control system that sits between the legacy phase-cut dimmer and the solid-state lighting. This intermediary measures the phase-cut signal characteristics and uses them to generate appropriate PWM dimming commands, acting as a mediator that translates legacy control signals into modern solid-state compatible commands, thereby eliminating direct incompatible interaction while preserving compatibility with existing infrastructure

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct electrical connection and analog phase-cut control mechanism with a digital measurement and control system. By using microcontrollers to measure phase-cut waveforms and generate digital PWM signals, the system substitutes the problematic direct phase-cut drive mechanism with a modern digital control approach that is inherently compatible with solid-state lighting while maintaining compatibility with legacy dimmers

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If smart PWM dimming devices are used for solid-state lighting, then precise dimming control is improved, but incompatibility with phase-cut dimmers causes user frustration

Engineering Contradiction:
Improvedimming control precisionVSAvoidcompatibility with phase-cut dimmers
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal dimming control system that can accept multiple types of input signals (phase-cut dimming signals) and output appropriate control commands (PWM signals) for solid-state lighting. The microcontroller-based system performs multiple functions: measuring input waveform characteristics, determining dimming levels, and generating appropriate output commands, thereby making the system compatible with both legacy phase-cut dimmers and modern solid-state lighting requirements

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

Solution Approach 2:

The patent changes the parameter representation and signal format from analog phase-cut waveforms to digital PWM commands. By measuring the characteristics of the phase-cut signal (such as the width of the cut portion) and converting this information into digital dimming level parameters, the system transforms incompatible signal types into a universal digital control language that works with both legacy dimmers and modern solid-state lighting

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If phase-cut dimming is applied to solid-state emitters, then energy cost reduction is improved, but erratic flickering occurs

Engineering Contradiction:
Improveenergy cost reductionVSAvoiderratic flickering
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent uses periodic PWM action at high frequency to drive the solid-state emitters, replacing the low-frequency phase-cut periodic action. By switching the power delivery in regular high-frequency pulses with controlled duty cycles, the system achieves both energy efficiency (through pulsed operation) and eliminates flickering (through frequency being above human perception threshold), while the microcontroller measures and adapts to the periodic phase-cut input signals

Inventive Principle:
Principle #19Periodic action

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 enables retro-compatible, adaptive, and flexible dimming options for solid-state lighting, reducing energy costs and improving user experience by providing precise dimming control and compatibility with existing phase-cut dimmers, while also enhancing noise tolerance and system robustness.

Implementation Method 1

a digital rectification module configured to rectify a phase-cut alternating current (AC) signal into: a rectified direct current (DC) power; and a rectified phase-cut signal

Methodology Applied
Scientific EffectRectification:

Implementation Method 2

The microcontroller may be configured to measure a duration of low and high states of a rectified phase-cut signal

Methodology Applied
Scientific EffectZero-crossing detection:

Data Source

PatentEP3662726B1Solid-state light source dimming system and techniques
Publication Date: 2021.04.28 LEDVANCE LLC
  • EP3662726B1 patent drawingFigure 1
  • EP3662726B1 patent drawingFigure 2~3
  • EP3662726B1 patent drawingFigure 4

AI summary

A system and related techniques for dimming a solid-state light source are disclosed. The system may be configured to dim the output of a solid-state emitter via a combination of phase-cut dimming and high-frequency pulse-width modulation (PWM) dimming. To this end, the system may include a digital rectification module configured to generate a rectified DC power and a rectified phase-cut signal based on a phase-cut AC signal received from a phase-cut dimmer. The system further may include a microcontroller unit (MCU) configured to measure the duration of low and high states of the rectified phase-cut signal using zero-crossing digital phase- cut detection and output PWM signal(s) based, at least in part, on those measured values. The rectified DC power and PWM signal(s) may be delivered to a DC-to-DC converter, which may output DC power(s) having an intensity based on the rectified DC power and PWM signal(s), causing receiving emitter(s) to dim.