LED Driver Circuit Reducing Power Consumption and Output Impedance

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Solution Overview

Problem

Conventional driver circuits for light-emitting components in optical data transmission suffer from high power requirements, high output resistance, low output voltage, and electromagnetic interference, limiting switching speed and efficiency, especially in applications with limited supply voltage.

Innovation Solution

A circuit arrangement that switches between two operating voltages using a low-impedance switching element, such as a MOSFET, to control the light-emitting component, minimizing current paths and parasitic capacitances, thereby reducing power consumption and output impedance, and enhancing switching speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional driver circuits with constant current sources are used to drive light-emitting components, then the light-emitting component can be supplied with necessary operating voltage and current, but the power consumption is high and the output voltage is low

Engineering Contradiction:
Improvepower consumptionVSAvoidoutput voltage
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The patent applies periodic action by switching between two operating voltages (first operating voltage and second operating voltage) to drive the light-emitting component. The switching element alternates between connecting the component to different voltage sources, creating a time-varying drive signal that achieves both low power consumption and high output voltage. This periodic switching replaces the continuous power consumption of conventional constant current sources.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by making the operating voltage variable through the switching element. Instead of using fixed constant current sources, the circuit dynamically switches between different voltage levels (first and second operating voltages) to optimize both power consumption and output voltage. The switching element enables the circuit to adapt its voltage output based on operational requirements.

Inventive Principle:
Principle #15Dynamics

2Speed

If conventional driver circuits with constant current sources are used, then the light-emitting component can be driven, but the output resistance is high which limits switching speed

Engineering Contradiction:
Improveswitching speedVSAvoidoutput resistance
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The periodic switching between different voltage sources creates a time-varying output that enables fast switching. The switching element, operated periodically, allows the circuit to transition rapidly between states, achieving high switching speed. This approach replaces the high output resistance of constant current sources with a low output impedance switching mechanism.

Inventive Principle:
Principle #19Periodic action

3Loss of energy

If conventional driver circuits with reactive loads and changeover switches are used, then current modulation can be achieved, but parasitic capacitances and voltage drops reduce efficiency

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcircuit complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates parasitic elements from the circuit by using a switching element with low parasitic capacitance. The design removes reactive loads and minimizes voltage drops by directly switching between voltage sources without intermediate reactive components. This extraction of harmful parasitic elements improves energy efficiency while maintaining manageable circuit complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Duration of action of moving object

If battery-powered devices with limited supply voltage are used, then portability is improved, but the operating time is limited due to high power consumption

Engineering Contradiction:
Improveoperating timeVSAvoidpower consumption
Core Design Contradiction:
Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The periodic switching between first and second operating voltages significantly reduces average power consumption compared to continuous constant current operation. By alternating between different voltage levels and utilizing the low impedance of the switching element, the circuit minimizes energy dissipation, thereby extending battery operating time in portable devices.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the voltage parameter dynamically by switching between different operating voltages. This parameter change allows the circuit to operate efficiently at different power levels, reducing average power consumption while maintaining adequate drive strength for the light-emitting component, thus extending battery life.

Inventive Principle:
Principle #35Parameter changes

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 approach achieves low power consumption, high switching speed, and high output voltage for the light-emitting component, improving transient response and extending the operating time in battery-powered devices.

Implementation Method 1

a first operating voltage is applied to an input terminal of a light-emitting component 20... a second operating voltage is applied to the input terminal of the light-emitting component 20

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2160927B1Circuit arrangement and method for controlling light-emitting components
Publication Date: 2021.04.14 SILICON LINE
  • EP2160927B1 patent drawingFigure 1~2
  • EP2160927B1 patent drawingFigure 3~4A
  • EP2160927B1 patent drawingFigure 4B~4C

AI summary

The invention relates to a circuit arrangement (100; 100'; 100''; 100'''), especially a driver circuit, and to a method for controlling at least one light-emitting component (20), of especially at least one electro-optical transducer, for example of at least one light-emitting diode (LED) or at least one laser such as e.g. at least one semiconductor laser, by switching at least one switching element (30) between at least one first switching position and a second switching position, the power being supplied by means of at least one supply element (10; 10'), especially by means of a voltage source or at least one current source that is supported by a capacitor on the output side. The aim of the invention is to improve said arrangement and said method in such a manner that the power requirement and output impedance are as low as possible, thereby obtaining as high a frequency or switching speed and as high an output voltage as possible for the light-emitting component (20). According to the invention, the light-emitting component (20) is controlled by varying its operating voltage, especially by switching between the switching positions, at least the first switching position and the second switching position of the operating frequency having a low impedance.