Optoelectronic Circuit with Dynamic LED Control for Flicker Reduction
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Solution Overview
Problem
Existing optoelectronic circuits powered by AC voltage suffer from prolonged phases without light emission and abrupt current interruptions, leading to perceived flickering and harmonic degradation when using light-emitting diodes.
Innovation Solution
An optoelectronic circuit with a control unit that manages a series of light-emitting diode assemblies and current sources, adjusting switch states and current intensity based on current and voltage thresholds to ensure continuous current variation and optimal light emission, using a combination of switches, current sensors, and a control unit to modulate the number of active diodes during voltage phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the number of light-emitting diodes is decreased to increase the duration of light-emission phases, then the duration of each phase ON is increased, but the electric power lost in the resistor is significant
Solution Approach 1:
The patent applies dynamics by making the number of active light-emitting diodes variable rather than fixed. The control unit dynamically adjusts which diodes are active based on the instantaneous voltage level during each half-cycle, ensuring that the maximum number of diodes conduct when voltage is high and progressively fewer diodes conduct as voltage decreases. This dynamic adaptation allows the system to maintain adequate light emission duration while minimizing resistive power losses by optimizing the number of conducting diodes to match the available voltage.
2Duration of action of moving object
If a switching circuit is used to progressively increase the number of light-emitting diodes during rising voltage phase, then the duration of phases without light emission is decreased, but the current flow is abruptly interrupted during voltage variation
Solution Approach 1:
The patent uses dynamics to progressively activate or deactivate light-emitting diodes during voltage transitions. During rising voltage phases, diodes are progressively activated in groups; during falling voltage phases, diodes are progressively deactivated. This staged, dynamic approach smooths current transitions and avoids abrupt interruptions, thereby maintaining current flow continuity while minimizing phases without light emission.
Solution Approach 2:
The control unit performs preliminary action by anticipating voltage changes and proactively adjusting the configuration of light-emitting diodes before significant voltage drops occur. By detecting voltage trends and preemptively reconfiguring the diode connections, the system prepares for upcoming voltage changes, ensuring smooth transitions and preventing abrupt current interruptions that would otherwise occur during falling voltage phases.
3Illumination intensity
If abrupt interruptions of current flow occur during voltage variation, then the light intensity supplied by light-emitting diodes shows time variations, but the harmonic factor of the current is degraded
Solution Approach 1:
The patent applies dynamics by continuously adapting the number of active light-emitting diodes to the instantaneous voltage level. During rising voltage phases, more diodes are activated to increase light intensity; during falling voltage phases, fewer diodes remain active. This dynamic adjustment ensures smooth current flow without abrupt interruptions, maintaining stable light intensity while preserving a good harmonic factor in the current waveform.
Solution Approach 2:
The patent changes the parameter of the number of active light-emitting diodes based on voltage conditions. By varying this parameter dynamically - increasing the number of active diodes when voltage rises and decreasing them when voltage falls - the system optimizes both light intensity output and current harmonic content, avoiding the harmful effects of abrupt current interruptions.
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 solution reduces the duration of non-emission phases and maintains continuous current flow, minimizing perceived flickering and improving the harmonic factor of the current, thus enhancing the performance and stability of the optoelectronic circuit.
Implementation Method 1
an optoelectronic circuit comprising light-emitting diodes
Implementation Method 2
light-emitting diodes 16 become conductive. Power supply current IALIM then follows power supply voltage VALIM
Data Source
AI summary
An optoelectronic circuit for receiving a variable voltage containing alternating increasing and decreasing phases. The optoelectronic circuit includes assemblies of light-emitting diodes mounted in series; a current source connected to each assembly by a switch; for each switch, a first comparison module for comparing the current passing through the switch with a current threshold; a second comparison module for comparing a voltage representing the voltage at the terminals of the current source with a voltage threshold; and a control module connected to the first and second comparison modules and designed to control the opening and closing of the switches, during each increasing phase and each decreasing phase, according to signals supplied by the first and second comparison modules.