Dummy Load Stabilizes LED Series Circuit Switching

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Solution Overview

Problem

Existing systems for controlling series-connected LEDs face issues with voltage and current variations during switching operations, leading to flickering and inefficiencies due to load surges when changing the number of illuminated LEDs, as the output voltage and current must adjust, causing disruptions in the electrical load.

Innovation Solution

A device with a dummy load connected in series to the LEDs, controlled by a controllable switch, compensates for load surges by adjusting its resistance value to match the LEDs' resistance, ensuring a constant current flow and preventing voltage peaks and breaks during switching operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the number of illuminated LEDs is changed by switching operations, then the brightness distribution can be adjusted, but voltage peaks and current breaks occur causing flickering

Engineering Contradiction:

Improvebrightness controlVSAvoidflickering prevention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The dummy load is activated in advance before the actual LED switching operation. When an LED is about to be switched off, the dummy load is switched on beforehand to maintain the total load resistance, preventing voltage peaks and current breaks that would cause flickering in already illuminated LEDs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dummy load acts as an intermediary element that compensates for changes in LED configuration. By having a controllable dummy load with adjustable resistance, the system can maintain constant total resistance during LED switching operations, thereby stabilizing the current and preventing flickering.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If LEDs are switched on or off individually, then brightness control is achieved, but load surges occur due to voltage and current variations

Engineering Contradiction:

Improveindividual LED controlVSAvoidload surge

Core Design Contradiction:

Ease of operationVSPower

Solution Approach 1:

The resistance value of the dummy load is dynamically adjusted to match the changing configuration of illuminated LEDs. By continuously adapting the dummy load resistance parameter, the total load resistance remains constant, preventing load surges and voltage peaks during individual LED switching operations.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the output voltage is adjusted to accommodate changing LED configurations, then the new number of LEDs can be operated, but current breakdown occurs in already illuminating LEDs

Engineering Contradiction:

ImproveLED configuration flexibilityVSAvoidcurrent stability

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Before changing the LED configuration, the dummy load is adjusted in advance to compensate for the upcoming change. This preliminary adjustment ensures that when LEDs are switched on or off, the total resistance remains constant, preventing current breakdown and maintaining stable operation of all LEDs.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8994278B2Device for controlling an electrical load

Publication Date: 2015.03.31 LEAR CORP GMBH

AI summary

A device serves to control an electrical load of at least two single loads connected in series. Each of the at least two single loads is connected in parallel to a controllable switch, so that each of the at least two single loads can be switched independently of one another. In addition, a driver stage that drives a current into the electrical load is present. The controllable switches can be controlled by the control unit. A dummy load is connected in series to the at least two single loads.