Resonant Damping Circuit for Triac Dimmable LED Drivers

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Solution Overview

Problem

Triac dimmer circuits cause sharp transitions in AC power waveforms, leading to flickering and inaccurate dimming in modern energy-efficient lighting systems like CFLs and LEDs, as they are not designed to handle the harsh edges and complex circuits of these systems.

Innovation Solution

A driver circuit with a rectifier, filter, edge detection, and dampening circuit that converts AC voltage to DC, filters the voltage, detects sharp transitions, and dampens resonant currents to stabilize the power supply and prevent flickering, allowing for smooth dimming of LEDs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a triac dimmer chops the AC power waveform to control lamp brightness, then incandescent lamps can be dimmed smoothly due to thermal inertia, but modern energy-efficient lighting systems experience flickering and inaccurate dimming due to sharp voltage transitions

Engineering Contradiction:

Improvedimming controlVSAvoidlight output stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces an intermediary circuit between the triac dimmer and the LED lamp that detects sharp voltage transitions and applies compensatory measures. The circuit includes a detection circuit that identifies edges in the chopped waveform and a dampening circuit that applies resistance during these transitions, mediating the harmful effects before they reach the LED driver.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary anti-action by detecting sharp voltage transitions before they can cause harmful effects and applying counter-measures in advance. The dampening circuit is activated preemptively during edge transitions to prevent flickering and inaccurate dimming before they occur.

Inventive Principle:

Principle #9Preliminary anti-action

2Use of energy by moving object

If modern energy-efficient lighting systems use complex circuits to improve energy efficiency and lamp life, then performance is enhanced, but the circuits become more sensitive to sharp voltage transitions from triac dimmers

Engineering Contradiction:

Improveenergy efficiencyVSAvoidsensitivity to voltage edges

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies beforehand cushioning by preparing compensatory measures in advance for the sharp voltage transitions. The dampening circuit is designed to be ready and activates automatically during edge transitions, cushioning the impact on the sensitive LED driver circuitry before harmful effects can occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the dampening circuit applies resistance during edge transitions to reduce flickering, then light output stability is improved, but power loss increases during these transitions

Engineering Contradiction:

Improvelight output stabilityVSAvoidpower loss during transitions

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies partial action by using the dampening circuit only during specific edge transitions rather than continuously. The detection circuit identifies when sharp transitions occur and activates the dampening resistance only during these brief moments, applying just enough correction to prevent flickering without wasting energy during normal operation.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The dampening circuit operates periodically rather than continuously, activating only during detected edge transitions in the chopped waveform. This periodic operation allows the system to maintain light output stability during critical moments while minimizing power loss during normal steady-state operation.

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

The solution provides a flicker-free, stable, and fully dimmable LED lighting system that operates efficiently with conventional AC dimming circuits, delivering constant current and maintaining lumen output across all dimming levels.

Implementation Method 1

a rectifier circuit to receive AC voltage and to convert the AC voltage to direct current ('DC') voltage

Methodology Applied

Scientific EffectRectification: Diode

Implementation Method 2

a filter circuit for filtering the DC voltage

Methodology Applied

Scientific EffectElectrical filtering: Filter (electronic)

Implementation Method 3

a dampening circuit for dampening the filtered current responsive to the detection circuit determining that the change in rectified DC voltage over the predetermined time interval exceeds a predetermined threshold

Methodology Applied

Scientific EffectResonant damping: Damping

Data Source

PatentUS8847498B2Resonant damping circuit for triac dimmable

Publication Date: 2014.09.30 TECHNICAL CONSUMER PRODUCTS INC

AI summary

A driver circuit for driving an LED includes a rectifier circuit to receive AC voltage and to convert the AC voltage to DC voltage. The driver circuit further includes a filter circuit for filtering the DC voltage. The driver circuit further includes a detection circuit for determining a change in the filtered DC voltage over a predetermined time interval. The driver circuit further includes a dampening circuit for dampening the filtered DC voltage responsive to the detection circuit determining that the change in filtered DC voltage over the predetermined time interval exceeds a predetermined threshold.