LED Current Divider Circuit for Uniform Parallel Chain Control
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Solution Overview
Problem
Existing solutions for controlling light-emitting diodes (LEDs) connected in series face challenges such as high circuitry-related expenditure, increased costs, voltage drops, and heat generation due to the need for multiple constant current sources and controllers when trying to achieve uniform brightness across multiple LED chains, especially in automotive applications with limited supply voltages.
Innovation Solution
A current divider arrangement using reference voltage generating units and controllable semiconductor switches, such as MOSFETs, is employed to accurately distribute a total current into partial currents across multiple LED chains connected in parallel, ensuring uniformity by generating control signals based on differences in reference voltages to regulate the semiconductor switches and adjust the current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple constant current sources are used to control multiple LED chains in parallel, then uniform current distribution is achieved, but circuit complexity and cost increase
Solution Approach 1:
The patent merges multiple constant current sources into a single constant current source that supplies current to multiple LED chains in parallel. A current divider arrangement with controllable semiconductor switches distributes the current uniformly to each LED chain, eliminating the need for multiple separate current sources while maintaining uniform current distribution.
Solution Approach 2:
The patent introduces a current divider arrangement as an intermediary component between the single constant current source and the multiple LED chains. This current divider uses controllable semiconductor switches to actively distribute and equalize the current among parallel LED chains, serving as a mediator that resolves the conflict between using fewer sources and maintaining uniform distribution.
2Measurement precision
If multiple controllers are used for each LED chain, then current control precision is improved, but power losses and heat generation increase
Solution Approach 1:
The patent combines multiple individual controllers into a single centralized control system that manages the current distribution for all LED chains. The current divider arrangement with controllable semiconductor switches is controlled by a single controller that adjusts the switching signals to achieve uniform current distribution, thereby reducing the number of active components and associated power losses.
3Device complexity
If a single constant current source is used for multiple LED chains, then cost and circuit complexity are reduced, but uniform current distribution becomes difficult to achieve
Solution Approach 1:
The patent introduces dynamic control through controllable semiconductor switches in the current divider arrangement. These switches are actively controlled to adjust and equalize the current distribution among parallel LED chains in real-time, transforming a static single-current-source system into a dynamically balanced system that achieves uniform current distribution despite the simplified circuit topology.
Solution Approach 2:
The patent implements feedback control where the controller monitors the current distribution and adjusts the switching signals to the controllable semiconductor switches accordingly. This feedback mechanism ensures that uniform current distribution is maintained across all LED chains even with variations in LED characteristics or operating conditions, while still using a single constant current source.
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 minimizes circuitry-related expenditure and power losses, achieving uniform current distribution with minimal tolerance and reduced heat generation, as demonstrated by experimental results showing a 0.6% difference in current distribution and 0.06% tolerance in reference voltages, while reducing the voltage drop across controllers compared to prior art.
Implementation Method 1
a first controllable semiconductor switch configured to control a current flowing through a first of the at least two LED chains
Implementation Method 2
a first means for current control of the first partial current Ia is provided in series connection with the first LED chain
Data Source
AI summary
An arrangement and a method for controlling a plurality of light emitting diodes which are connected in series to attain uniform distribution of a total current to several series connections, LED chains, connected in parallel to each other wherein circuitry-related expenditure and power losses occurring during the control process are minimized, include a first reference voltage generating unit and a second reference voltage generating unit, wherein a outlet of the first reference voltage generating unit is connected to a first and a second control circuit, and an outlet of the second reference voltage generating unit is connected to the second and the first control circuit, and an outlet of the first control circuit is connected to a control inlet of the first controllable semiconductor switch, and an outlet of the second control circuit is connected to a control inlet of the second controllable semiconductor switch.