Series LED Circuit with Current Regulator for Voltage Matching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional lighting systems, particularly those using incandescent and fluorescent bulbs, are inefficient in energy usage and have short lifespans, and solid state light emitters like LEDs face challenges in achieving high efficacy and color rendering index (CRI) while requiring inefficient voltage conversion and generating excessive heat.

Innovation Solution

A circuit for a lighting device that includes series strings of solid state light emitters with a series current regulator, optionally with a rectifier and capacitor, and a fan for cooling, which minimizes power loss by matching the forward voltage of the string to the line voltage, and employs a high number of LEDs for efficient energy use and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional voltage conversion methods are used for solid state light emitters, then voltage matching is achieved, but power loss increases and efficiency decreases

Engineering Contradiction:

Improveenergy efficiencyVSAvoidpower loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent connects solid state light emitters in series to match the forward voltage of the string to the line voltage, creating an equipotential condition that eliminates the need for voltage conversion. This resolves the contradiction by achieving both voltage matching and minimal power loss simultaneously.

Inventive Principle:

Principle #12Equipotentiality

Solution Approach 2:

The patent removes the voltage conversion stage from the system entirely by directly connecting the series string of solid state light emitters to the line voltage. This extraction of the problematic voltage conversion component eliminates the associated power losses while maintaining proper voltage matching.

Inventive Principle:

Principle #2Taking out (Extraction)

2Use of energy by moving object

If solid state light emitters are used, then energy efficiency is improved, but heat generation increases

Engineering Contradiction:

Improveenergy efficiencyVSAvoidheat generation

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent converts the harmful heat generated by solid state light emitters into a manageable thermal management problem by implementing a heat sink with specific thermal conductivity requirements. The heat sink draws thermal energy from the LEDs, converting the harmful heat into a controllable thermal flow that can be dissipated to the environment.

Inventive Principle:

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

3Use of energy by moving object

If high number of LEDs are connected in series, then voltage matching improves, but circuit complexity increases

Engineering Contradiction:

Improvevoltage matchingVSAvoidcircuit complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent changes the electrical parameters of the solid state light emitters by connecting them in series, which increases the total forward voltage of the string to match the line voltage. This parameter change achieves proper voltage matching while maintaining relatively simple circuit topology.

Inventive Principle:

Principle #35Parameter changes

4Loss of energy

If series connection of solid state light emitters is used, then power loss is reduced, but reliability decreases due to single point of failure

Engineering Contradiction:

Improvepower lossVSAvoidsystem reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent divides the lighting system into multiple parallel circuits, each containing a series string of solid state light emitters. This segmentation creates redundancy where failure of one string does not affect the others, improving reliability while maintaining the low power loss benefits of series connection within each string.

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

The solution achieves high lumen output (>700 lumens) with good efficacy (>40 lumen/watt) and reduced heat generation, providing a lightweight, efficient, and attractive lighting solution.

Implementation Method 1

Light emitting diodes are semiconductor devices that convert electrical current into light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a fan for cooling

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Data Source

PatentUS7852009B2Lighting device circuit with series-connected solid state light emitters and current regulator

Publication Date: 2010.12.14 LED-IP MANAGEMENT LLC

AI summary

A circuit for a lighting device comprises a sub-circuit which comprises a series current regulator and a group of solid state light emitters. The current regulator and the solid state light emitters are arranged in series. In some embodiments, the circuit further comprises a fan electrically connected in series in the sub-circuit. In some embodiments, the circuit further comprises a second sub-circuit which comprises a second series current regulator and a second group of solid state light emitters, the first sub-circuit and the second sub-circuit being arranged in parallel. In some embodiments, an anode of the series current regulator is electrically connected to a cathode of one of the solid state light emitters. Also, methods of lighting wherein a sum of voltage drops across light emitters and a current regulator is in the range of from 1.2 to 1.6 times the line voltage.