Laser Driver Circuit Periodic Switching for Power Efficiency

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Solution Overview

Problem

In optical data transmission, existing NRZ modulation schemes require constant current supply to light-emitting components, leading to inefficient power usage due to threshold current requirements, especially in semiconductor lasers.

Innovation Solution

A circuit arrangement that periodically switches between zero current and maximum current for logic '1' transmission, optimizing the duty cycle to reduce average current and enhance power efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If constant current is supplied to light-emitting component to maintain threshold current, then reliable light emission is achieved, but electrical power consumption increases

Engineering Contradiction:
Improvelight emission reliabilityVSAvoidelectrical power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by switching the current to the light-emitting component between zero and a maximum value that exceeds the threshold current. The switching occurs at a frequency sufficient to maintain average current above the threshold level, enabling reliable light emission while consuming less electrical power than continuous constant current supply would require

Inventive Principle:
Principle #19Periodic action

2Reliability

If threshold current is continuously maintained through separate current-limiting element, then light-emitting component operates reliably, but device complexity increases

Engineering Contradiction:
Improvelight-emitting component operationVSAvoidcircuit arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple current-limiting elements into a single switching element that operates in conjunction with a data signal. The switching element combines the threshold current maintenance function with the data transmission function, eliminating the need for separate current-limiting elements and reducing overall circuit complexity

Inventive Principle:
Principle #5Merging (Combining)

3Power

If maximum current is supplied to achieve nominal conversion efficiency, then optical output power increases, but electrical power consumption increases proportionally

Engineering Contradiction:
Improveoptical output powerVSAvoidelectrical power consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic switching between zero current and maximum current (which exceeds threshold current) to deliver optical output power. By controlling the duty cycle of the switching, the system achieves the required average optical output power while consuming less electrical power than continuous maximum current supply would require, thus improving power efficiency

Inventive Principle:
Principle #19Periodic action

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 significantly increases power efficiency by eliminating the need for constant threshold current supply, resulting in higher optical output power with reduced electrical power consumption.

Implementation Method 1

at least one light-emitting component (50) with a threshold current Ith to be afflicted, in particular an electro-optical converter, for example a laser, such as a semiconductor laser

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Data Source

PatentEP2294729B1Circuit arrangement and method for controlling light emitting components
Publication Date: 2016.01.06 SILICON LINE
  • EP2294729B1 patent drawingFigure 1~4
  • EP2294729B1 patent drawingFigure 5~7
  • EP2294729B1 patent drawingFigure 8A~8B

AI summary

The invention relates to a circuit arrangement (100; 100'), in particular a driver circuit, and to a method for controlling at least one light emitting component (50), to which a surge current (Ith) is applied, in particular for controlling at least one electro-optical transducer, for example at least one laser, such as a semiconductor laser, said circuit arrangement (100; 100') being supplied with current by means of at least one supply element (10), in particular by means of at least one current source and said light emitting component (50) being controlled by means of at least one switching element (30) situated between at least one current-limiting element (20) and the light emitting component (50) using at least one reversing controller (40). The aim of the invention is to further develop a circuit arrangement of this type in such a way that the performance is significantly improved in comparison to prior art. To achieve this, a maximum value (Imax) is provided for the current (I) by means of the current-limiting element (20) and that the logic "1" of the data to be transmitted (D) by means of the light emitting component (50) is represented by periodic switching between the zero value (I=0) of the current (I) and the maximum value (Imax) of the current (I) supplied to the light emitting component (50).