LED String Current Regulator Circuit for Uniform Brightness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LED illumination systems, multiple LED strings connected in series often experience uneven current distribution due to differences in load characteristics, leading to unsatisfactory uniformity in output brightness, and conventional current adjustment circuits fail to adequately compensate for resistance differences, resulting in unbalanced currents and high power consumption.
Innovation Solution
A current regulating circuit comprising a capacitor, inductor, diode, switch, and detection circuit is used to detect and control the terminal voltage of each LED string, ensuring equal currents flow through them, and the energy storage and release characteristics of capacitors and inductors facilitate energy recycling, reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple LED strings are connected in series to increase the required amount of LED, then the illumination coverage is improved, but the uniformity of output brightness deteriorates due to different load characteristics causing uneven current distribution
Solution Approach 1:
The patent divides the LED system into multiple independent LED strings, each equipped with its own current regulating circuit. This segmentation allows independent control of current in each string, enabling the system to accommodate a larger total amount of LED while maintaining uniform brightness across all strings through individualized current regulation.
2Illumination intensity
If conventional current adjustment circuits are used to equalize currents in multiple LED strings, then the current uniformity is improved, but the power consumption increases due to resistive states of switches
Solution Approach 1:
The patent changes the operating parameters of the current regulating circuit by using switches that operate in resonant states rather than resistive states. This parameter change allows the circuit to achieve current equalization across LED strings while minimizing power loss, as resonant switching reduces the energy dissipated during switching operations compared to traditional resistive switching.
3Illumination intensity
If switches are turned on to adjust voltages on LED string terminals, then the current distribution is improved, but the resistance differences among LED strings are not satisfactorily compensated due to resistive states
Solution Approach 1:
The patent replaces the mechanical/resistive switching mechanism with a resonant switching mechanism. Instead of relying on resistive states to adjust voltages, the system uses resonant oscillations to achieve voltage and current equalization. This substitution eliminates the inherent resistance losses and improves the effectiveness of compensation for LED string variations.
4Power
If multiple LED strings are employed to meet application requirements, then the illumination capacity is improved, but the input current from power converter cannot be evenly distributed due to resistance differences
Solution Approach 1:
The patent implements feedback control in each current regulating circuit, where the circuit continuously monitors the current in its associated LED string and adjusts the resonant switching parameters accordingly. This feedback mechanism ensures that input current from the power converter is evenly distributed across all LED strings, maintaining uniform illumination capacity while compensating for resistance differences through active regulation.
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 stabilizes current flow through LED strings, achieving uniform brightness and reducing power consumption by recycling energy, thereby addressing the issue of uneven brightness and high power usage in LED illumination systems.
Implementation Method 1
The capacitor includes a first terminal and a second terminal, the first terminal of the capacitor is electrically coupled to the low voltage, and the second terminal of the capacitor is electrically coupled to a preset voltage
Implementation Method 2
The inductor includes a first terminal and a second terminal, and the first terminal of the inductor is electrically coupled to the low voltage
Implementation Method 3
The diode includes a positive terminal and a negative terminal, the positive terminal of the diode is electrically coupled to the second terminal of the inductor, and the negative terminal of the diode is electrically coupled to the high voltage
Data Source
AI summary
An exemplary current regulating circuit of LED string includes a capacitor, an inductor, a diode, a switch and a detection circuit. First and second terminals of the capacitor respectively are connected to a low voltage and a preset voltage. A first terminal of the inductor is connected to the low voltage. Positive and negative terminals of the diode are respectively connected to a second terminal of the inductor and a high voltage. First and second terminals of the switch are respectively connected to the second terminal of the inductor and the preset voltage. The detection circuit detects the low voltage to thereby switch ON-OFF states of the switch in demand. Moreover, a LED illumination device using the current regulating circuit also is provided.