TRIAC Dimmer Power Interface with Pulsed Current Shaping

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Solution Overview

Problem

Low power consumption of solid state light sources, such as LED lamps, causes compatibility issues with TRIAC-based dimmers, leading to flickering or permanent shutdown due to insufficient load current, especially at low wattages below 40 W, where the minimum load requirement of the dimmer circuit is not met.

Innovation Solution

A power interface with a current shaper that periodically interrupts and re-establishes current flow from the adjustable power supply circuit to maintain a conducting state, ensuring the current through the circuit remains above the holding current level, even when the average current consumption is lower, using a boost converter to generate pulsed currents that keep the dimmer on while minimizing perceivable fluctuations in light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a TRIAC-based dimmer is used to control LED light sources, then power consumption can be reduced and dimming functionality is achieved, but the LED light source may flicker or permanently switch off at low dimming levels due to insufficient load current

Engineering Contradiction:

Improvepower consumptionVSAvoidoperational stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies periodic action by using a boost converter to generate periodic current pulses during the TRIAC conduction period. These pulses ensure the holding current requirement is met while maintaining low average power consumption. The converter operates at a frequency that produces perceivable light output without flickering, thus resolving the contradiction between energy savings and operational stability.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If the load power is reduced below 40 W to achieve energy efficiency, then power consumption is improved, but the minimum load requirement of the TRIAC dimmer is not reached causing chaotic operation

Engineering Contradiction:

Improvepower consumptionVSAvoiddimmer compatibility

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent introduces a boost converter as an intermediary device between the LED driver and the TRIAC dimmer. This intermediary actively shapes the current waveform to satisfy the TRIAC's minimum load requirement, enabling low-power LED operation (below 40 W) while maintaining full dimmer compatibility. The converter acts as a buffer that decouples the low power consumption goal from the dimmer's minimum load constraint.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a special switch mode power supply is used to shape current consumption to meet TRIAC holding current requirements, then dimmer compatibility is improved, but power consumption increases to more than 10 W

Engineering Contradiction:

Improvedimmer compatibilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic pulsed current generation through a boost converter to meet TRIAC holding current requirements. By delivering high current only during brief pulses within the TRIAC conduction period rather than continuously, the system maintains dimmer compatibility while keeping average power consumption well below the 10 W threshold, thus resolving the contradiction between adaptability and energy use.

Inventive Principle:

Principle #19Periodic action

4Reliability

If continuous high frequency current is consumed to keep the TRIAC in the on state, then operational stability is improved, but the load must still draw the TRIAC holding current resulting in increased power consumption

Engineering Contradiction:

Improveconducting state maintenanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic current pulsing through a boost converter that delivers high current only during specific intervals within the TRIAC conduction period. This periodic action maintains the TRIAC in the on state by periodically reinforcing the holding current, while the intervals between pulses allow power consumption to average well below continuous levels, thus resolving the contradiction between reliability and energy use.

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

Enables the operation of LED light sources at low wattages with TRIAC-dimmers by maintaining the dimmer in a conducting state, reducing flickering and ensuring continuous operation, while optimizing power consumption and circuit design.

Implementation Method 1

using a boost converter to generate pulsed currents that keep the dimmer on

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentUS8680779B2Power interface with LEDs for a TRIAC dimmer

Publication Date: 2014.03.25 KONINKLIJKE PHILIPS NV

AI summary

A power interface is proposed, which keeps an adjustable power supply circuit in a conducting state even if the average current consumption of an attached load is below the adjustable power supply circuit's holding current requirement. The power interface makes use of the dynamic properties of adjustable power supply circuits. Due to the recovery time of the adjustable power supply circuit, it will stay in the conducting state even if there is no current flowing for a short while. The power interface makes use of this effect by interrupting and re-establishing a current flow from the adjustable power supply circuit.