LED Running Light Control via Series Coupled Bypass Circuits
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Solution Overview
Problem
Current automotive LED running light turn signal technologies are costly and complex, requiring multiple control lines and high assembly complexity, which complicates installation and manufacturing, while also failing to provide the same noticeability as incandescent turn signals due to rapid on/off events of LEDs.
Innovation Solution
A series coupled LED running light system with a bypass circuit and adjustable current sink, where each LED block cell has a self-driven electronic circuit with a Zener diode and transistors to sequentially turn on LEDs as voltage increases, simplifying control and diagnostics, and using a microcontroller for voltage reference and current control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LED control circuits are used, then LED turn signal functionality is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent implements self-driven LED blocks where each block contains its own bypass circuitry (transistors Q1-Q4, resistors R1-R4, and capacitor C1) that automatically controls current flow based on voltage thresholds. This eliminates the need for external microcontroller control of individual LEDs, reducing overall system complexity while maintaining reliable turn signal functionality through autonomous local decision-making at each LED block.
2Ease of operation
If multiple control lines are used for LED control, then precise LED control is achieved, but ease of manufacture and installation deteriorates
Solution Approach 1:
The patent merges multiple control functions into a single control line that carries a ramp voltage signal. All LED blocks respond to the same voltage threshold (approximately 2.0V) on this single line, eliminating the need for separate control lines for each LED. This consolidation dramatically simplifies wiring and assembly while maintaining precise control over the sequential LED activation pattern.
3Use of energy by moving object
If rapid LED on/off events are used, then energy efficiency is improved, but noticeability deteriorates
Solution Approach 1:
The patent implements a ramp voltage waveform that periodically increases over time, causing LED blocks to illuminate in sequence rather than switching rapidly on and off. This periodic ramp action creates a visible running light effect that mimics traditional incandescent turn signals, maintaining high noticeability while still using energy-efficient LED technology. The gradual voltage increase allows each LED block to remain illuminated long enough to be clearly perceived.
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 complexity and cost, enhances noticeability by mimicking incandescent light intensity changes, and provides robust diagnostics and reliability for safety-critical automotive applications with simplified interfaces and adaptive timing.
Implementation Method 1
the certain voltage value may be determined by a zener diode breakdown voltage
Data Source
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AI summary
A light emitting diode (LED) running light comprises a current sink and a plurality of series coupled LED block cells; each of the plurality of LED block cells comprising a LED and a bypass circuit to the current sink, wherein each series coupled LED sequentially turns on (lights) when a voltage source increases by additive voltage increments of at least the turn-on voltage of each LED in the series coupled string until all LEDs are on (lit). The current sink maintains a desired current value through the LEDs and may also be used to provide waveforms for diagnostic and timing purposes