Independent DC-DC Converters for LED String Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current LED-based lighting systems face limitations in efficiency and color temperature control, as they require complex electronics to drive LEDs efficiently and achieve desired color temperatures, with existing solutions not fully optimizing the use of DC-DC converters for independent LED string control.

Innovation Solution

The implementation of multiple independent DC-DC converters, which convert AC power into specific drive voltages and currents for strings of LEDs, allowing for buck, boost, or buck-boost conversions, and enabling independent control of drive currents and voltages for each LED string to mix light into desired white light color temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If multiple independent DC-DC converters are used to drive different LED strings, then color temperature control and efficiency are improved, but device complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidconverter circuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The power conversion system is segmented into multiple independent DC-DC converter circuits, where each converter is dedicated to driving a specific LED string. This segmentation allows independent optimization of each converter for its specific LED string requirements, improving overall energy efficiency while maintaining manageable complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each DC-DC converter circuit is designed to be universally applicable to different LED string configurations and can operate in different conversion modes (buck, boost, or buck-boost). This multi-functionality allows the same converter design to handle various voltage and current requirements across different LED strings, improving efficiency without proportionally increasing complexity

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

2Illumination intensity

If independent DC-DC converters are used for each LED string, then color temperature control is improved, but device complexity increases

Engineering Contradiction:
Improvecolor temperature controlVSAvoidconverter circuit complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The lighting system is divided into multiple LED strings, each driven by a dedicated DC-DC converter. This segmentation enables independent control of each string's output characteristics, allowing precise adjustment of color temperature by varying the drive current to each string according to its specific LED characteristics

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each DC-DC converter is designed with dynamic control capability to adjust its output current based on real-time requirements. The converters can dynamically switch between different conversion modes (buck, boost, buck-boost) and adjust their duty cycles to maintain optimal color temperature control as operating conditions change

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If separate DC-DC conversion paths are used for different LED strings, then drive current control is improved, but device complexity increases

Engineering Contradiction:
Improvedrive current controlVSAvoidconverter circuit complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control system is segmented into independent control loops for each DC-DC converter, allowing separate optimization of control parameters for each LED string. Each converter can be independently tuned for its specific LED string characteristics, improving ease of operation without requiring complex coordinated control of a single converter

Inventive Principle:
Principle #1Segmentation

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

This solution enhances the efficiency and color temperature control of LED-based lighting systems by allowing for flexible and independent control of LED strings, improving lumen output and color performance while reducing complexity and energy consumption.

Implementation Method 1

The first converter circuitry converts the rectified signal into a first drive voltage for a first string of LEDs and provides a first drive current for the first string of LEDs

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP2893776B1Lighting component with independent DC-DC converters
Publication Date: 2018.12.19 WOLFSPEED INC
  • EP2893776B1 patent drawingFigure 1~2
  • EP2893776B1 patent drawingFigure 3
  • EP2893776B1 patent drawingFigure 4

AI summary

The present disclosure relates to a lighting component with multiple DC-DC converters. Each of the DC-DC converters is used to independently drive a corresponding string of LEDs. In general, rectifier circuitry receives an AC power signal and generates a rectified signal, which is provided to first and second converter circuitries. The first converter circuitry converts the rectified signal into a first drive voltage for a first string of LEDs and provides a first drive current for the first string of LEDs based on a first drive current control signal. Similarly, the second converter circuitry converts the rectified signal into a second drive voltage for a second string of LEDs and provides a second drive current for the second string of LEDs based on a second drive current control signal.