LED Module Piecewise Current Control for AC Efficiency
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Solution Overview
Problem
Existing AC-driven LED technologies, such as inverse-parallel and bridge-rectifying topologies, suffer from low luminous efficiency and availability due to inefficient current control, leading to suboptimal instantaneous luminous areas and power factor.
Innovation Solution
A light-emitting diode module with a system in package (SIP) topology that incorporates a bridge rectifying unit, a light-emitting diode unit, and an integrated circuit unit with constant-current sources and switch elements controlled by a controller to provide piecewise current control, including piecewise constant-current and variant-current control, to optimize light emission based on the AC voltage source magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If bridge-rectifying topology is used to increase instantaneous luminous areas, then the number of illuminated micro diodes increases, but luminous efficiency decreases due to insufficient current control
Solution Approach 1:
The patent implements dynamic piecewise current control where the constant-current source is selectively activated based on the instantaneous AC voltage magnitude. The controller adjusts the driving current dynamically across different voltage ranges (first, second, and third regions), optimizing the balance between luminous output and energy consumption at each operating point rather than using a fixed current control scheme.
Solution Approach 2:
The patent changes the current control parameter from a fixed constant current to a piecewise variable current that adapts to the AC voltage magnitude. By defining different current values (Ic1, Ic2, Ic3) for different voltage regions and using a constant-current source that switches between these values, the system optimizes luminous efficiency across the entire operating range while maintaining high instantaneous luminous area.
2Device complexity
If inverse-parallel topology is used to simplify circuit structure, then device complexity is reduced, but availability decreases because only half of micro diodes illuminate simultaneously
Solution Approach 1:
The patent makes all micro diodes in the bridge-rectifying circuit universally illuminable by implementing piecewise current control that activates appropriate constant-current sources for different voltage ranges. This ensures that micro diodes can illuminate during both positive and negative half-cycles of AC input, maximizing availability while maintaining the circuit's structural simplicity.
3Device complexity
If constant current control is used to simplify control circuitry, then device complexity is reduced, but luminous efficiency decreases due to continuous operation at high current
Solution Approach 1:
The patent transitions from static constant current control to dynamic piecewise constant current control. The controller selectively activates different constant-current sources (first, second, or third constant-current sources) based on the instantaneous AC voltage magnitude, optimizing energy consumption at each operating point while maintaining simple constant-current control circuitry for each region.
Solution Approach 2:
The patent implements periodic switching of constant-current sources synchronized with the AC voltage cycle. As the AC voltage varies periodically through different magnitude ranges, the controller periodically switches between different constant-current sources to match the voltage levels, ensuring optimal luminous efficiency throughout the entire AC cycle.
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 piecewise current control significantly increases the luminous efficiency and availability of the LEDs by lengthening the lighting time and improving the power factor of the AC-driven light-emitting diode module, while the SIP topology simplifies the package process and minimizes the module size.
Implementation Method 1
a light-emitting diode unit and an integrated circuit unit... The light-emitting diode unit is electrically connected to the voltage source and driven by the voltage source
Data Source
AI summary
A light-emitting diode (LED) module and a method for operating the same are disclosed. The LED module is supplied through an external voltage source. The LED module includes a bridge rectifying unit, a LED unit, and an integrated circuit (IC) unit. The bridge rectifying unit rectifies the external voltage source into an inner DC voltage source. The LED unit is electrically connected to the bridge rectifying unit and driven through the DC voltage source. The IC unit is electrically connected to the bridge rectifying unit and the LED unit and is supplied through the DC voltage source, thus providing a piecewise constant-current control or a piecewise variant-current control to the LED unit.