LED Driver Circuit Voltage Adaptation

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Solution Overview

Problem

Existing driver circuits for vehicle lights, particularly LEDs, face challenges in maintaining consistent lighting when power supply voltage drops below nominal values, leading to insufficient voltage for all connected LEDs, resulting in flickering or reduced luminosity, especially during 'Start and Stop' conditions.

Innovation Solution

A driver circuit that dynamically adjusts the configuration of LED connections between parallel and serial configurations based on power supply voltage, using switching means and control logic to modify the number of lighting branches and sources per branch, ensuring optimal lighting and reduced power absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If several LEDs are connected in series to increase lighting output, then the lighting intensity is improved, but the power supply voltage requirement increases, causing insufficient voltage during low voltage conditions

Engineering Contradiction:
Improvelighting intensityVSAvoidlighting stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent implements dynamic reconfiguration of the LED matrix from a fixed serial structure to an adaptable structure that can switch between serial and parallel connections based on power supply voltage conditions. The control unit monitors voltage and automatically adjusts the connection topology, allowing the system to maintain reliable operation across varying voltage conditions while preserving high lighting intensity when voltage is sufficient.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical connection parameter (series/parallel configuration) of the LED matrix based on power supply voltage levels. When voltage is high, LEDs are connected in series to maximize lighting intensity; when voltage drops, the configuration switches to parallel to ensure continuous operation, thereby resolving the contradiction between intensity and reliability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the number of LEDs per lighting branch is reduced to maintain operation at low voltage, then the voltage requirement is reduced, but the total current absorption increases, leading to higher power dissipation

Engineering Contradiction:
Improveoperation continuityVSAvoidpower dissipation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the number of active lighting branches and their configuration based on voltage conditions. At low voltage, fewer branches operate in parallel rather than reducing LEDs per branch, minimizing current multiplication and power dissipation while maintaining operation continuity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The LED matrix is segmented into multiple independently controllable lighting branches that can be selectively activated. The control unit manages which branches are active based on voltage conditions, allowing the system to optimize between lighting output and power consumption without compromising operational reliability.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If a fixed LED matrix configuration is used, then the circuit design is simple, but the system cannot adapt to varying power supply voltage, resulting in flickering or insufficient lighting

Engineering Contradiction:
Improvecircuit design simplicityVSAvoidvoltage adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static LED matrix into a dynamic reconfigurable structure with switching means that can change connection topology based on voltage conditions. This adds adaptability while maintaining reasonable design complexity through systematic control of the switching elements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The LED matrix is designed to serve multiple functions through reconfiguration: it can operate as a serial string for high-intensity lighting when voltage permits, or as parallel branches for reliable operation at low voltage. This multi-functionality resolves the contradiction between simplicity and adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2624662B1LED driver circuit, method of driving and vehicle light
Publication Date: 2024.11.27 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP2624662B1 patent drawingFigure 1
  • EP2624662B1 patent drawingFigure 2
  • EP2624662B1 patent drawingFigure 3~3b

AI summary

A driver circuit of lighting sources for powering a plurality of lighting sources, comprising switching means (20) which can be operated to modify the path of the overall power supply electric current crossing said lighting sources. Said switching means can be operated to switch the path of the overall power supply electric current between at least one first path, corresponding to a first circuit configuration of the interconnections between the lighting sources, and at least one second path, corresponding to a second circuit configuration of the interconnections between the lighting sources.