LED String Shunt Regulation for Fan Power
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Solution Overview
Problem
Existing LED lamp power supplies face inefficiencies due to the need for separate voltage regulation for DC fans, which results in significant power dissipation and reduced efficacy during dimming, especially in phase-control dimmable AC-mains LED lamps intended for general illumination.
Innovation Solution
Utilizing forward-biased LED junctions as shunt regulators to provide a stable voltage for the fan, reducing power dissipation and achieving near 100% efficiency by diverting current from the LEDs to the fan, thereby maintaining light output without additional components or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate voltage regulator is used to power the DC fan, then the fan can operate reliably, but power dissipation increases and efficiency decreases
Solution Approach 1:
The patent merges the fan power supply function with the LED string by connecting the fan in parallel across the LED string. The LED string serves dual purposes: generating light and providing voltage regulation for the fan through its forward voltage characteristics, eliminating the need for a separate voltage regulator and reducing power dissipation.
Solution Approach 2:
The LED string is given multiple functions: it serves as both the light source and the voltage regulator for the fan motor. By utilizing the forward voltage drop characteristics of the LED string, the system eliminates dedicated regulation components, achieving multi-functionality with a single component.
2Stability of the object's composition
If traditional linear regulation is used for fan voltage, then voltage stability is achieved, but efficiency drops significantly during dimming
Solution Approach 1:
The patent replaces the traditional linear voltage regulation mechanism (which dissipates excess voltage as heat) with a direct connection to the LED string. The LED string's inherent forward voltage characteristics provide natural voltage regulation without the need for dissipative linear regulation, substituting a passive electrical characteristic for an active regulation mechanism.
3Ease of operation
If the fan is connected to a separate power supply, then power management is simplified, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into the LED string: light generation and voltage regulation for the fan. By eliminating separate voltage regulators and dedicated fan power supplies, the system reduces component count and overall device complexity while maintaining proper power management.
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 approach enhances the efficiency of LED lamp power supplies by minimizing power loss and maintaining light output, even during dimming, by using the LED string as a shunt regulator, resulting in a more efficient and cost-effective solution for LED lamp power management.
Implementation Method 1
utilizing forward-biased LED junctions as shunt regulators to provide a stable voltage for the fan
Implementation Method 2
diverting current from the LEDs to the fan
Implementation Method 3
A direct current cooling fan has a first input line and a second input line operatively connected across at least one of the light emitting diodes and has a cooling air delivery direction positioned to cool a surface in thermal contact with a heat generating portion of at least one of the power supply and the string of light emitting diodes
Data Source
AI summary
In one general aspect, the invention features an illumination source that includes a power supply having alternating current input lines and positive and negative direct current output lines. A string of light emitting diodes is connected in series between the positive and negative direct current output lines in a forward-biased series. A direct current cooling fan has a first input line and a second input line operatively connected across at least one of the light emitting diodes and has a cooling air delivery direction positioned to cool a surface in thermal contact with a heat generating portion of at least one of the power supply and the string of light emitting diodes.