Driver Circuit for Solid State Light Sources Color Mixing

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Solution Overview

Problem

Conventional driver circuits for solid state light sources face challenges in fitting into small form factor lighting fixtures while meeting high power factor and efficacy requirements, especially when color mixing is needed, as they require separate drivers for each color or use wavelength-converted LEDs with lower efficacy.

Innovation Solution

A driver circuit that includes a rectifier, switching converter, and mixing circuit to switch solid state light sources between 'on' and 'off' states based on the rectified AC input, allowing for color mixing within a single device without separate controllers for each color, using a mixing circuit that controls the conductive state of solid state light sources in response to the rectified AC voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate driver circuits are used for each color of solid state light source, then color mixing can be achieved, but device complexity and space requirements increase

Engineering Contradiction:
Improvecolor mixing capabilityVSAvoiddriver circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple solid state light sources of different colors into a single lighting device with one integrated driver circuit. The driver circuit includes a rectifier, switching converter, and mixing circuit that collectively control multiple LEDs of different colors, eliminating the need for separate driver circuits for each color while maintaining color mixing capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The driver circuit is designed as a universal control system that can handle multiple types of solid state light sources simultaneously. The mixing circuit within the driver can selectively control current distribution to different colored LEDs, providing multi-functional control from a single circuit rather than requiring dedicated drivers for each color type.

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

2Device complexity

If wavelength-converted solid state light sources are used for color mixing, then a single driver circuit can be used, but efficacy (lumens-per-watt) decreases

Engineering Contradiction:
Improvedriver circuit configurationVSAvoidefficacy
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The mixing circuit employs periodic switching action to control current flow through different colored solid state light sources. By rapidly switching between different LED colors in response to the rectified AC voltage half-waves, the circuit achieves color mixing through temporal modulation rather than relying on wavelength conversion, thereby maintaining higher efficacy while using a single driver.

Inventive Principle:
Principle #19Periodic action

3Area of stationary object

If a single driver circuit controls multiple colored solid state light sources, then space is reduced, but control precision for each color becomes more difficult

Engineering Contradiction:
Improvedriver circuit areaVSAvoidcurrent control precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The mixing circuit acts as an intermediary between the single driver circuit and multiple colored solid state light sources. It receives the rectified AC voltage and selectively controls current distribution to different LED colors through switching elements, enabling precise control of each color channel while maintaining a compact single-driver architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 compact configuration for color mixing in small form factor applications while maintaining high efficacy, avoiding the need for separate drivers and potentially using non-wavelength-converted LEDs, thus improving power factor and lumens-per-watt performance.

Implementation Method 1

a rectifier circuit configured to receive an alternating current (AC) input voltage and to provide a rectified AC voltage

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 2

a switching converter circuit coupled to a light source including one or more solid state light sources, the switching converter circuit configured to provide a direct current (DC) output to the light source in response to the rectified AC voltage

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a light source including one or more solid state light sources

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2850916B1Driver circuit for solid state light sources
Publication Date: 2018.11.14 OSRAM SYLVANIA INC
  • EP2850916B1 patent drawingFigure 1~2
  • EP2850916B1 patent drawingFigure 3~4
  • EP2850916B1 patent drawingFigure 5

AI summary

A driver circuit (102) for a light source (106) including one or more solid state light sources, a luminaire including the same, and a method of so driving the solid state light sources are provided. The driver circuit (102) includes a rectifier circuit (202) that receives an alternating current (AC) input voltage and provides a rectified AC voltage. The driver circuit (102) also includes a switching converter circuit (204) coupled to the light source (106). The switching converter circuit (204) provides a direct current (DC) output to the light source (106) in response to the rectified AC voltage. The driver circuit (102) also includes a mixing circuit (206), coupled to the light source (106), to switch current through at least one solid state light source of the light source (106) in response to each of a plurality of consecutive half-waves of the rectified AC voltage.