LED Control Unit Optimizing Dimming Resolution and Power Efficiency
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Solution Overview
Problem
Conventional LED lighting systems face inefficiencies in power consumption and dimming resolution, especially at lower intensities, due to limitations in duty cycle modulation and current control, leading to noticeable changes in brightness and potential overheating.
Innovation Solution
A control unit is introduced to manage the duty cycles and current of LED units in series, allowing for adjusted duty cycles and reduced current levels to maintain desired brightness while optimizing power efficiency, and a capacitor is used to mitigate current ripple, ensuring smooth current delivery and extended LED lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If duty cycle modulation is used to control LED intensity, then power consumption is reduced at lower intensities, but dimming resolution deteriorates and brightness changes become noticeable
Solution Approach 1:
The patent changes the operating parameters of the LED driver by adjusting both the duty cycle and the forward current simultaneously. Instead of only varying duty cycle, the system modifies the current level to compensate for resolution loss, maintaining smooth dimming while achieving power savings through reduced current operation at low intensities
Solution Approach 2:
The system dynamically adjusts multiple parameters (duty cycle and forward current) based on the desired output intensity. The control algorithm continuously optimizes the combination of these parameters to maintain high dimming resolution across the entire brightness range while minimizing power consumption
2Use of energy by moving object
If duty cycle is reduced to lower intensity, then power consumption decreases, but brightness control precision worsens
Solution Approach 1:
The patent employs dual parameter adjustment by simultaneously modifying duty cycle and forward current. This approach allows the system to maintain precise brightness control even when operating at reduced power levels, as the current adjustment compensates for the coarsening effect of duty cycle reduction
3Productivity
If nominal current is maintained for efficient power supply operation, then power efficiency is improved, but heat generation increases at reduced brightness
Solution Approach 1:
The system dynamically adjusts the forward current based on the required output brightness level. At reduced brightness settings, the current is lowered proportionally, which reduces power dissipation and heat generation in the LED and driver circuitry, while maintaining high overall power efficiency through optimized operating points
4Reliability
If current is reduced to extend LED lifespan, then reliability is improved, but power efficiency of the driver decreases
Solution Approach 1:
The patent optimizes the relationship between forward current and duty cycle to maintain high driver efficiency while operating at reduced current levels. By adjusting both parameters simultaneously, the system keeps the driver operating in its efficient range even when delivering reduced current to extend LED lifespan
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 power efficiency, improves dimming resolution, and extends LED lifespan by optimizing current delivery and reducing heat-related issues, particularly at high brightness levels.
Implementation Method 1
a capacitor connectable in parallel to the first and second LED units by operating a switch connected in series with the capacitor
Data Source
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AI summary
A lighting system comprising - an LED assembly comprising a first LED unit and a capacitor connectable in parallel to the first LED unit by operating a switch connected in series with the capacitor; - a switched mode power supply for, in use, powering the LED assembly, and - a control unit comprising: - an input port for receiving an input signal; - an output port for providing a control signal to the switched mode power supply and the switch, the control unit being arranged to - receive an input signal representing a desired output characteristic of the LED assembly, - determine a power supply current for the switched mode power supply from the received input signal, - provide, via the output port, a power supply control signal to the switched mode power supply to control the switched mode power supply to provide the power supply current to the LED assembly; and provide, via the output port, a switch control signal to control the switch based on at least one of the power supply current and the input signal.