LED Lighting Circuit with Shared Array for Curved Dimming

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Solution Overview

Problem

Conventional LED lighting circuits with two arrays can only approximate the dimming behavior of incandescent lamps by following a straight line in color space, which is perceived as unnatural due to the higher cost of drivers and inability to mimic the curved black body locus.

Innovation Solution

A lighting circuit configuration using two drivers to control three arrays of LEDs, where one array is shared between both drivers, allowing for a 'virtual' third driver to achieve any color path through a two-dimensional color space, including curved paths, by adjusting current distribution and overlap durations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If two drivers are used to control two LED arrays, then the device complexity is reduced, but the ability to follow curved black body locus is lost

Engineering Contradiction:
Improvenumber of driversVSAvoidability to follow curved black body locus
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent merges the control functions by having two drivers share a common LED array. The first driver controls the first LED array and shares the second LED array with the second driver. This sharing arrangement creates a virtual third driver effect, enabling curved black body locus following while maintaining only two physical drivers, thus resolving the contradiction between device complexity and adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second LED array serves multiple functions: it is controlled by the first driver to contribute to warm white light, and simultaneously controlled by the second driver to contribute to cool white light. This multi-functionality allows the system to achieve three-color-point mixing capability with only two drivers, resolving the contradiction by making one driver-controlled array universal in its function.

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

2Adaptability or versatility

If three drivers are used for three LED arrays, then the ability to follow curved black body locus is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveability to follow curved black body locusVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges the control functions by having two drivers share a common LED array. The first driver controls the first LED array and shares the second LED array with the second driver. This sharing arrangement creates a virtual third driver effect, enabling curved black body locus following while maintaining only two physical drivers, thus resolving the contradiction between device complexity and adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second LED array serves multiple functions: it is controlled by the first driver to contribute to warm white light, and simultaneously controlled by the second driver to contribute to cool white light. This multi-functionality allows the system to achieve three-color-point mixing capability with only two drivers, resolving the contradiction by making one driver-controlled array universal in its function.

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

3Ease of manufacture

If two drivers control two LED arrays, then the manufacturing cost is reduced, but the dimming behavior appears unnatural

Engineering Contradiction:
Improvemanufacturing costVSAvoidnaturalness of dimming behavior
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent merges the control functions by having two drivers share a common LED array. The first driver controls the first LED array and shares the second LED array with the second driver. This sharing arrangement creates a virtual third driver effect, enabling curved black body locus following while maintaining only two physical drivers, thus resolving the contradiction between device complexity and adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second LED array serves multiple functions: it is controlled by the first driver to contribute to warm white light, and simultaneously controlled by the second driver to contribute to cool white light. This multi-functionality allows the system to achieve three-color-point mixing capability with only two drivers, resolving the contradiction by making one driver-controlled array universal in its function.

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

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 LED lighting circuit to mimic the dimming behavior of incandescent lamps by following a curved black body locus, providing a more natural lighting experience while reducing the number of required drivers and associated costs.

Implementation Method 1

An LED light source generally comprises an array of LEDs

Methodology Applied
Scientific EffectLight-emitting diode: Light Emitting Diode

Implementation Method 2

Light-emitting diodes (LEDs) are being used to replace conventional light sources

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3597008B1LED lighting circuit
Publication Date: 2021.12.29 LUMILEDS LLC
  • EP3597008B1 patent drawingFigure 1
  • EP3597008B1 patent drawingFigure 2
  • EP3597008B1 patent drawingFigure 3

AI summary

The invention describes a lighting circuit (1) comprising a first array (S1) of semiconductor light sources (L1) and a separate second array (S2) of semiconductor light sources (L2); a shared array (SH) of semiconductor light sources (LH); a first driver (11) arranged to drive the first array (S1) and the shared array (SH); and a second driver (12) arranged to drive the shared array (SH) and the second array(S2). The invention further describes a method of manufacturing such a lighting circuit (1); and a method of controlling such a lighting circuit (1).