LED Driver Circuit Current Surge Control

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Solution Overview

Problem

Existing power supply circuits for LED series circuits face issues with current overshoot during switch transitions, leading to potential damage and insufficient current during energy storage changes, which can result in reduced luminosity or functional restrictions.

Innovation Solution

A device that measures current and energy content through the LED chain and energy storage, using a controller to adjust switch states and duty cycles to maintain constant energy supply within predefined limits, preventing uncontrolled current changes and detecting faulty consumers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If switches are opened or closed to control LED series circuits, then the load can be dimmed or short-circuited, but current overshoot occurs during closing which can damage the downstream load

Engineering Contradiction:
Improveload control capabilityVSAvoidcurrent overshoot damage
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The controller monitors the instantaneous current during switch transitions and predicts current overshoot before it occurs. When overshoot is anticipated during a closing operation, the controller prevents the switch from closing or limits its closure, thereby preventing damage to the downstream load before it can occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously measures the instantaneous current through the LED series circuit and feeds this information back to the controller. The controller uses this feedback to detect current overshoot conditions and dynamically adjusts switch operations to prevent harmful current levels, creating a closed-loop control system that prevents damage.

Inventive Principle:
Principle #23Feedback

2Loss of energy

If switches are opened to reduce load, then current consumption is reduced, but insufficient current is available until energy store is recharged which restricts function

Engineering Contradiction:
Improveenergy consumption reductionVSAvoidfunctional availability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The controller dynamically adjusts the duty cycle of switching elements based on real-time monitoring of instantaneous current and energy store status. This dynamic control allows the system to optimize between energy savings and functional availability, adjusting operations to maintain reliability while minimizing energy consumption during normal operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller monitors energy store charge levels in advance and predicts when insufficient current conditions may occur. By detecting low energy store status before it causes functional restrictions, the controller can take preliminary actions such as adjusting switch timing or preventing opens that would cause insufficient current, thereby maintaining functional availability.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If current source directly supplies LED series circuit, then simple control is achieved, but uncontrolled current changes occur during switch transitions

Engineering Contradiction:
Improvecontrol circuit simplicityVSAvoidcurrent stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The system implements current monitoring with feedback control where the controller continuously measures instantaneous current through the LED series circuit and uses this feedback to detect and respond to current changes during switch transitions, stabilizing the current despite the simple current source architecture.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The controller acts as an intermediary between the simple current source and the LED series circuit. It monitors current conditions and mediates switch operations to prevent uncontrolled current changes, adding stability without requiring complexification of the current source itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3128813B1Device for supplying light sources with energy in a manner that increases their service life, by reducing current/voltage surges
Publication Date: 2018.09.19 ELMOS SEMICON AG
  • EP3128813B1 patent drawingFigure 1
  • EP3128813B1 patent drawingFigure 2
  • EP3128813B1 patent drawingFigure 3

AI summary

The invention relates to a circuit (7) for supplying power to a sequential circuit, typically of non-linear loads (4, 10), using a current source (1). Preferably, the load is a series circuit of LEDs (4, 10). This current-driven load, preferably an LED series circuit (4, 10), consisting of one to N elements, is partially short-circuited and thus dimmed.