Parallel Lighting Strand Circuit Single Switching Element

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Solution Overview

Problem

Existing circuit arrangements for vehicle headlights require two signals to switch between lighting strands, making them costly and inefficient, and alternative designs are unsuitable for vehicle applications.

Innovation Solution

A circuit arrangement that uses a single switching element to alternately switch between two parallel-connected lighting strands by adjusting the voltage within the working range of each strand, allowing for operation with a single signal line referencing a reference potential, such as ground potential, using a relay or transistor as the switching element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If two switching elements are used to control two lighting strands, then each strand can be independently controlled, but the device complexity and cost increase

Engineering Contradiction:
ImproveIndependent control of lighting strandsVSAvoidNumber of switching elements
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines two separate switching elements into a single switching element that controls both lighting strands alternately. The single switching element is switched on and off in sequence to distribute current between the two parallel-connected lighting strands, thereby reducing device complexity while maintaining the ability to control each strand independently through temporal separation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements periodic switching of the single switching element to achieve alternating control of the two lighting strands. By switching the element on and off at specific intervals, the system creates periodic current distribution patterns that allow each strand to receive appropriate current during its designated time period, effectively achieving independent control through time-division multiplexing.

Inventive Principle:
Principle #19Periodic action

2Reliability

If two switching elements are used for strand control, then switching reliability improves, but the cost and circuit complexity increase

Engineering Contradiction:
ImproveSwitching control reliabilityVSAvoidNumber of switching elements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges two switching elements into one, reducing component count and potential failure points. The single switching element is designed to handle the total current requirement by alternating between the two lighting strands, ensuring that at any given moment, the full current capacity is available to the active strand, thereby maintaining reliability while simplifying the circuit.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent incorporates preliminary design considerations in the switching element's operation, where the switching timing and duration are pre-calculated based on the lighting strands' current requirements. This preliminary action ensures that each strand receives the appropriate current for the required duration, maintaining reliable control without needing redundant switching elements.

Inventive Principle:
Principle #10Preliminary action

3Illumination intensity

If voltage is increased to operate high-voltage lighting strands, then lighting performance improves, but the risk of overvoltage damage increases

Engineering Contradiction:
ImproveLighting outputVSAvoidOvervoltage damage risk
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent uses periodic switching to control the single switching element, allowing each lighting strand to receive high voltage only during its designated time period when it is the active strand. The other strand remains disconnected during this period, protecting it from overvoltage damage. This time-division approach enables high-voltage operation for optimal lighting performance while preventing simultaneous exposure that would cause damage.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The switching element acts as an intermediary between the power source and the lighting strands, controlling the flow of high voltage to each strand in sequence. By inserting this switching mediator, the system can deliver the high voltage necessary for optimal lighting performance to the active strand while preventing high voltage from reaching the inactive strand, thereby eliminating the overvoltage damage risk.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reliable and cost-effective switching between lighting strands with a single signal, eliminating the need for a second switching element and optimizing energy distribution within the specified voltage range for automotive use.

Implementation Method 1

a first lighting string (2) is connected in series with a switching element (6), by which the single switching element (6) can be switched between the states 'conducting' and 'non-conducting'

Methodology Applied
Scientific EffectTransistor switching:

Implementation Method 2

The switching element (6) can be a relay or a transistor, in particular a MOSFET or a bipolar transistor

Methodology Applied
Scientific EffectRelay switching: Relay

Implementation Method 3

a parallel circuit (4) having at least two electrically parallel connected lighting strings (2, 3)

Methodology Applied
Scientific EffectElectrical conduction in parallel circuits: Conduction (electrical)

Data Source

PatentEP3525552B1Circuit arrangement for switching on and off at least two light strands for a vehicle headlight electrically connected in parallel
Publication Date: 2023.10.11 ZKW GRP GMBH
  • EP3525552B1 patent drawingFigure 1

AI summary

The invention relates to a circuit arrangement (1) for the alternating switching on and off of at least two electrically parallel connected light strings for a vehicle headlight, comprising a parallel circuit having at least two electrically parallel connected light strings, wherein each light string consists of a number of light sources (7) connected electrically in series, at least one energy source (5) for supplying the parallel circuit (4), wherein the parallel circuit (4) is connected to the energy source (5) in such a way and/or the energy source (5) is designed such that in a conducting state of the switching element (6) the voltage applied to the parallel circuit (4) is within the operating range of the first light string (2) and thereby the first light string (2) is switched on and the second light string (3) is switched off.and that in a non-conductive state of the switching element (6) the voltage applied to the parallel circuit (4) is increased towards the operating range of the second lighting string (3) and thus the first lighting string (2) is switched off and the second lighting string (3) is switched on.