LED Driver Circuit Segmentation for High Voltage Efficiency
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Solution Overview
Problem
Conventional light source driving circuits experience a decrease in power efficiency and increased heat dissipation when faced with higher input AC voltages, leading to noticeable variations in brightness and inefficient power management.
Innovation Solution
The proposed light source driving circuit employs a rectifier, capacitor, and a controller with multiple current regulators and switches to selectively control the current through multiple LED strings based on varying DC voltage levels, ensuring that only the necessary LED strings are activated to maintain constant output power and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional driving circuit uses a single LED string with linear control, then the circuit structure is simple, but the power efficiency decreases significantly when input AC voltage increases (from 84% to 71%)
Solution Approach 1:
The patent divides the LED load into multiple independent LED strings (first LED string and second LED string) that can be selectively activated. The controller selectively turns on only the necessary LED string based on input voltage levels, preventing unnecessary power consumption and maintaining high efficiency across varying voltage conditions.
Solution Approach 2:
The patent implements dynamic control where the controller adjusts the operating state of different LED strings based on real-time input voltage detection. When input voltage is high, the controller activates only the second LED string; when input voltage is normal, it activates the first LED string, creating a dynamic adaptation that optimizes power efficiency.
2Device complexity
If a conventional driving circuit uses linear control of a single LED string, then the control mechanism is simple, but noticeable brightness variations occur when input AC voltage changes
Solution Approach 1:
By segmenting the LED load into multiple independent strings with different forward voltage characteristics, the patent enables selective activation that maintains consistent brightness. The controller compensates for input voltage variations by choosing which LED string to activate, ensuring uniform illumination output.
Solution Approach 2:
The patent changes the operating parameters by selecting different LED strings based on input voltage levels. Each LED string has specific forward voltage characteristics that match certain input voltage ranges, allowing the system to maintain constant brightness by matching the appropriate LED string to the current input conditions.
3Power
If a conventional driving circuit operates with higher input AC voltage, then the available power increases, but power loss and heat dissipation increase significantly
Solution Approach 1:
The patent applies partial action by activating only the necessary LED string based on available power levels. When input voltage is high, the controller activates only the second LED string rather than all LED strings, preventing excessive power loss and heat dissipation while still providing adequate illumination.
Solution Approach 2:
The system changes its operating parameters by detecting input voltage levels and selecting appropriate LED strings accordingly. This parameter adaptation ensures that power consumption is optimized for the available input power, minimizing waste and heat generation while maintaining efficient operation.
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 enhances power efficiency by maintaining constant output power and minimizing noticeable brightness variations, achieving up to 92.3% efficiency compared to the conventional 77% when AC voltage is high, while reducing heat dissipation and extending the operational life of LED light sources.
Implementation Method 1
The rectifier 104 can be a bridge rectifier including four diodes for rectifying an AC voltage VAC from a power source 102 to a rectified AC voltage
Implementation Method 2
The capacitor 106 filters the rectified AC voltage and provides a substantially constant DC voltage VDC
Implementation Method 3
Light-emitting diodes (LEDs) generate virtually no heat and utilize a fraction of the energy to produce an equivalent lumen of lighting
Data Source
AI summary
A light source driving circuit for powering a first light source and a second light source by a DC voltage includes a first current regulator, a second current regulator and a controller. The first current regulator controls a first switch coupled to the first light source based on a first current reference and a first sensing signal. The second current regulator controls a second switch coupled to the second light source based on a second current reference and a second sensing signal. The controller regulates the current through the first light source and the current through the second light source by controlling the first current regulator and the second current regulator. If the DC voltage is within a first range, then the controller turns on the first light source. If the DC voltage is within a second range, then the controller turns on the first light source and the second light source.