LED Lighting Module Actuation via Dynamic Mode Switching
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Solution Overview
Problem
Light sources with multiple LEDs do not operate sufficiently brightly at low operating voltages, such as 6 V, due to the exponential diode characteristic, and existing solutions like step-up converters increase complexity and cost.
Innovation Solution
A circuit that alternates the activation of semiconductor light-emitting elements using a single step-down converter, allowing efficient operation at reduced brightness by adjusting the operating voltage, eliminating the need for additional components like step-up converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a step-up converter is added to increase operating voltage for reduced brightness operation, then the light source can operate sufficiently brightly at low voltage, but the device becomes more expensive and larger
Solution Approach 1:
The patent applies dynamic switching between two operating modes: a first mode where all LEDs are activated for full brightness, and a second mode where only a subset of LEDs is activated for reduced brightness. This dynamic reconfiguration allows the system to adapt to different voltage conditions without requiring additional hardware like step-up converters.
Solution Approach 2:
The patent implements periodic alternation between different LED activation states. In the second operating mode, the control device periodically switches between activating different subsets of LEDs, creating a time-averaged reduced brightness effect while maintaining the ability to operate from low voltage inputs.
2Power
If multiple LEDs are connected in series, then the light source can operate at full brightness with higher voltage, but the luminous flux becomes too low at reduced voltage due to exponential diode characteristic
Solution Approach 1:
The patent segments the series-connected LEDs into multiple groups or subsets. Instead of activating all LEDs simultaneously, the control device selectively activates only a portion of the LED subsets in the second operating mode. This segmentation allows the operating voltage to be effectively distributed across fewer LEDs, maintaining sufficient luminous flux at reduced overall brightness.
Solution Approach 2:
The patent changes the operational parameters by dynamically adjusting which LED subsets are active based on the input voltage level. When voltage is low, the system transitions to a parameter state where fewer LEDs are activated, effectively changing the electrical load and operating point to match the available voltage while maintaining acceptable brightness.
3Ease of operation
If a step-down converter is used to set forward voltage from operating voltage, then the light source can operate at full brightness, but the light source does not glow sufficiently brightly at low operating voltage
Solution Approach 1:
The patent makes the lighting system universal by enabling it to operate effectively across a wide voltage range without requiring different hardware configurations. The same step-down converter and LED array can operate in multiple modes: full brightness with all LEDs active at higher voltages, and reduced brightness with subset LEDs active at lower voltages. This multi-functionality eliminates the need for voltage-specific hardware variants.
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
Enables efficient operation of LEDs at reduced brightness without perceived flicker, maintaining energy efficiency and reducing costs by using a single step-down converter for both full and reduced brightness modes.
Implementation Method 1
a step-down converter can be used to set this forward voltage, starting from the operating voltage in the range of 8 V to 16 V
Implementation Method 2
a plurality of series-connected semiconductor light-emitting elements, in particular light-emitting diodes (LEDs)
Implementation Method 3
the luminous flux of the light-emitting diode is already too low at the operating voltage of 6 V due to the exponential diode characteristic
Data Source
AI summary
The invention relates to a circuit and method for actuating a lighting module, comprising at least two semiconductor elements (D1, D2) which are connected in series in a first operating mode. Upon dropping below a predetermined threshold value of an operating voltage (101), a second operating mode is detected (102) and the at least two semiconductor light elements (D1, D2) are alternately actuated (102, S1, S2) in the second operating mode.