LED Driving Apparatus with Dynamic Duty Cycle Control
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Solution Overview
Problem
Conventional LED driving circuits face efficiency reduction and overheating issues due to variations in forward voltage of LED arrays, particularly in linear mode type circuits, which can lead to reliability problems and increased size and cost.
Innovation Solution
A DC-DC converter and control unit system that provides a driving voltage to multiple LED arrays, with switching units varying current flow and duty cycles within a predetermined headroom voltage range, ensuring efficient operation and reducing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linear mode type circuit is used to control current of each LED array, then the size of the circuit is reduced and the price is lowered, but heat generation increases and efficiency decreases due to forward voltage variations
Solution Approach 1:
The patent applies dynamic control by varying the duty cycle of switching components based on detected forward voltage variations of each LED array. The control unit adjusts the on-time proportion of switching components dynamically to compensate for voltage differences, allowing the circuit to adapt to changing conditions and maintain efficiency while reducing heat generation.
Solution Approach 2:
The patent changes the operating parameters of the switching components, specifically adjusting the duty cycle parameter in response to detected forward voltage variations. By modifying this control parameter dynamically, the system optimizes current distribution across LED arrays with different forward voltages, reducing power loss and heat generation while maintaining compact circuit size.
2Reliability
If a switch mode type circuit is used to control current of each LED array, then current control is maintained regardless of forward voltage variations, but the size and price of the circuit are increased due to redundant power components
Solution Approach 1:
The patent merges multiple power components into a shared power supply unit that serves all LED arrays simultaneously. Instead of providing complete power conversion circuits for each LED array, the system uses a single DC-DC converter that distributes power to multiple arrays through switching components, eliminating redundancy while maintaining current control stability.
Solution Approach 2:
The patent implements multi-functionality by designing a single DC-DC converter that can supply and regulate power to multiple LED arrays with different forward voltage characteristics. The converter performs universal power conversion and distribution functions for all arrays, while individual switching components handle array-specific current control, reducing overall circuit complexity.
3Adaptability or versatility
If the forward voltage variation of LED arrays increases, then the adaptability of the circuit to different LED specifications is improved, but heat generation in the linear switch increases causing reliability problems
Solution Approach 1:
The patent implements feedback control by detecting the forward voltage of each LED array and using this information to adjust the duty cycle of switching components. The control unit continuously monitors voltage variations and dynamically adjusts switching parameters, creating a closed-loop system that adapts to forward voltage changes while preventing excessive heat generation and maintaining switch reliability.
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 effectively reduces heat and maintains efficiency by controlling current and voltage within optimal ranges, preventing overheating and current distortion, while minimizing circuit size and cost.
Implementation Method 1
a plurality of switching units, each of the switching units being connected in series to a corresponding LED array of the plurality of LED arrays and varying a size of a driving current to flow in the corresponding LED array
Implementation Method 2
a DC-DC converter which provides a driving voltage to a plurality of LED arrays
Data Source
AI summary
A light emitting diode (LED) driving apparatus includes a DC-DC converter which provides a driving voltage to a plurality of LED arrays; a plurality of switching units, each of the switching units being connected in series to a corresponding LED array of the plurality of LED arrays and varying a size of a driving current to flow in the corresponding LED array of the plurality of LED arrays; and a control unit which, in order for each of the switching units to operate within a predetermined headroom voltage range, calculates a driving current of each of the plurality of LED arrays and a duty cycle of the switching units corresponding to each of the plurality of LED arrays, and controls the plurality of switching units based on the calculated driving current and the calculated duty cycle.