LED Lighting Package With Matched Forward Voltage Strings

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Solution Overview

Problem

Existing LED lighting packages face inefficiencies when combining LEDs of different colors due to voltage differences, leading to excessive power dissipation and heat generation, limiting their use to low-power applications and making them unsuitable for space-constrained or high-power scenarios.

Innovation Solution

The solution involves arranging multiple series-connected LEDs of different colors in parallel with matched forward voltages, each connected to a linear regulator, ensuring that the total forward voltage of each string is equivalent, thereby minimizing power dissipation in the regulators and allowing for higher power and more efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If linear regulators are used to compensate for voltage differences between different colored LEDs, then the LEDs can operate at different forward voltages, but power dissipation increases and efficiency decreases

Engineering Contradiction:

Improveability to combine different colored LEDsVSAvoidpower dissipation

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent changes the operating parameters by using DC-DC converters instead of linear regulators, transitioning from voltage compensation to active power conversion. This allows the system to handle different forward voltages of different colored LEDs (red ~2V, green/blue/white ~3V) while minimizing power loss through efficient switching conversion rather than resistive dissipation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the linear regulator mechanism (which dissipates power as heat) with an electronic DC-DC conversion mechanism. This substitution eliminates the need for voltage compensation through power dissipation and enables efficient operation with mid- to high-power LEDs of different colors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of energy

If DC-DC converters are used per LED to minimize losses, then power efficiency improves, but the driver size increases and space requirements are not met

Engineering Contradiction:

Improvepower lossVSAvoiddriver size

Core Design Contradiction:

Loss of energyVSArea of stationary object

Solution Approach 1:

The patent merges multiple separate DC-DC converter functions into a single integrated driver circuit that can control multiple different-colored LEDs. This consolidation maintains the power efficiency benefits of DC-DC conversion while reducing the overall driver size to fit within compact LED package configurations.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal driver architecture that can handle multiple LED colors and power levels through a single integrated circuit. This multi-functional driver eliminates the need for separate converters for each LED, achieving both space efficiency and power efficiency simultaneously.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If mid- to high-power LEDs are used to increase luminous output, then light output improves, but power dissipation in linear regulators increases making them unsuitable

Engineering Contradiction:

Improveluminous outputVSAvoidregulator power dissipation

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The patent replaces linear regulators with DC-DC converters, enabling the use of mid- to high-power LEDs that draw higher currents. The DC-DC conversion efficiency prevents the exponential increase in power dissipation that would occur with linear regulators, allowing high luminous output while maintaining acceptable power loss levels.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11284489B2LED lighting package

Publication Date: 2022.03.22 LUMILEDS SINGAPORE PTE LTD

AI summary

An LED lighting package is described that contains a first LED string with a plurality of series-connected light-emitting diodes and a first linear regulator arranged to determine the current through the first LED string. At least one further LED string includes a plurality of series-connected light-emitting diodes of a different color, and a further linear regulator is arranged to determine the current through that LED string. The different colored LED strings are connected in parallel. A common voltage supply is used for the LED strings. The number of light-emitting diodes in the first LED string exceeds the number of light-emitting diodes in each further LED string (, and the number of light-emitting diodes in each LED string is chosen such that the total forward voltage of a further LED string is essentially the same as the total forward voltage of the first LED string.