Adaptive Interface Circuit for LED Dimmer Flicker and Inrush Current

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Solution Overview

Problem

Existing LED driver circuits are incompatible with conventional dimmer switches, leading to issues like flicker and large inrush currents, and fail to support stable operation when used with both incandescent and LED lamps in parallel.

Innovation Solution

A system with adaptive interface circuits that include resistive and reactive impedances, coupled with a controller to modulate current paths and damp oscillations, allowing seamless operation with phase-modulated dimmer switches and switching power supplies, ensuring stable power conversion and compatibility with existing lighting infrastructure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing LED driver circuits are used with conventional dimmer switches, then LED power conversion is achieved, but flicker and large inrush currents occur

Engineering Contradiction:

Improvestable operationVSAvoidflicker and inrush currents

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces adaptive interface circuits as intermediary components between the LED driver and dimmer switch. These circuits include resistive and reactive impedances that mediate the interaction, filtering harmful effects like flicker and inrush currents while allowing the dimmer to control LED brightness. The interface circuit acts as a buffer that translates dimmer control signals into stable LED driver input.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful inrush current and flicker effects into useful control mechanisms. By using resistive and reactive impedances in the adaptive interface, the circuit intentionally introduces controlled resistance and reactance that dampen oscillations and limit current surges, transforming what would be harmful effects into stabilizing features that protect the LED driver and improve reliability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If LED drivers are designed for stable operation with dimmer switches, then compatibility with existing lighting infrastructure is achieved, but device complexity increases

Engineering Contradiction:

Improvecompatibility with lighting infrastructureVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The adaptive interface circuit is designed to work with multiple types of dimmer switches and LED driver configurations through a universal architecture. The resistive and reactive impedance components can be adjusted to match different dimmer characteristics, allowing the same basic circuit topology to accommodate various existing lighting infrastructure configurations without requiring custom designs for each scenario.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs dynamic impedance matching where the resistive and reactive components of the adaptive interface circuit can be adjusted based on operating conditions. This dynamic adjustment allows the circuit to adapt to different dimmer switch characteristics and load conditions, maintaining compatibility across various infrastructure configurations while managing complexity through adaptive rather than static design.

Inventive Principle:

Principle #15Dynamics

3Stability of the object's composition

If adaptive interface circuits with resistive and reactive impedances are added, then oscillation damping and stability are improved, but device complexity increases

Engineering Contradiction:

Improveoperational stabilityVSAvoidcircuit component count

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent achieves oscillation damping and stability improvement by carefully selecting and adjusting the parameter values of resistive and reactive impedance components. Rather than adding complex active control circuits, the solution modifies passive component parameters (resistance values, reactance values) to naturally dampen oscillations and stabilize operation, achieving enhanced stability through parameter optimization rather than structural complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9148922B2Power conversion apparatus and system for solid state lighting

Publication Date: 2015.09.29 CHEMTRON RESEARCH LLC

AI summary

Exemplary embodiments provide for power conversion for solid state lighting coupled to a first switch, such as a dimmer switch. An exemplary apparatus includes a switching power supply and a first adaptive interface circuit. The first adaptive interface circuit may include a resistive impedance coupled in series to a reactive impedance. The apparatus may also include a second adaptive interface circuit including a second switch coupled to the reactive impedance. The second adaptive interface circuit is configured to conduct current from the first switch in a second current path. At least one of the first and second adaptive interface circuits may be configured to damp oscillation when the first switch turns on.