Constant-Current Drive Circuit Eliminating Stroboscopic Phenomenon

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Solution Overview

Problem

Existing Boost circuits require additional de-stroboscopic circuits, leading to higher driving costs and larger size due to the use of film capacitors, which cause stroboscopic phenomena and inefficiencies.

Innovation Solution

A constant-current drive circuit incorporating a rectifier module, electrolytic capacitor, driver module, and electromagnetic suppression module to eliminate stroboscopic effects and clutter interference, utilizing a driver chip with over-voltage protection, under-voltage lockout, current detection, and pulse width modulation to maintain constant current in discontinuous conduction mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If film capacitors are used for filtering in Boost circuits, then filtering effect is achieved, but stroboscopic phenomenon occurs and driving cost increases

Engineering Contradiction:
Improvefiltering effectVSAvoidstroboscopic phenomenon
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the type of capacitor from film capacitor to electrolytic capacitor, altering the electrical parameters of the filtering circuit. This parameter change eliminates the stroboscopic phenomenon while maintaining the filtering effect, as electrolytic capacitors have different capacitance characteristics that prevent the oscillatory behavior caused by film capacitors.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive film capacitors with more cost-effective electrolytic capacitors. This substitution reduces driving cost while achieving the desired filtering performance without stroboscopic effects, making the solution more economically viable for LED driving applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-generated harmful factors

If additional de-stroboscopic circuit is added, then stroboscopic phenomenon is eliminated, but driving space increases

Engineering Contradiction:
Improvestroboscopic phenomenonVSAvoiddriving space
Core Design Contradiction:
Object-generated harmful factorsVSVolume of moving object

Solution Approach 1:

The patent extracts the de-stroboscopic function from a separate additional circuit and integrates it into the capacitor selection within the existing filtering circuit. By using electrolytic capacitors that inherently prevent stroboscopic phenomena, the need for separate de-stroboscopic components is eliminated, thus reducing driving space.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The electrolytic capacitor serves multiple functions simultaneously: it acts as the filtering capacitor for DC voltage smoothing and also functions as the de-stroboscopic element by its inherent electrical characteristics. This multi-functionality eliminates the need for additional dedicated de-stroboscopic circuitry, reducing overall circuit complexity and space requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If Boost circuit is used for LED driving, then voltage conversion is achieved, but electromagnetic interference increases

Engineering Contradiction:
Improvevoltage conversionVSAvoidelectromagnetic interference
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful electromagnetic interference generated by the Boost circuit into beneficial effects through careful circuit design. By using electrolytic capacitors with appropriate capacitance values and adding electromagnetic suppression modules, the circuit transforms EMI into useful electromagnetic fields that aid in current regulation and reduce noise, thereby improving overall electromagnetic compatibility.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The solution reduces driving costs and space requirements by improving circuit efficiency and electromagnetic performance, eliminating stroboscopic phenomena and clutter interference, thereby maintaining constant current output.

Implementation Method 1

The electrolytic capacitor is connected to the rectifier module, and configured to improve an efficiency of circuit and eliminate a stroboscopic phenomenon in the DC voltage signal

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The rectifier module is configured to receive an AC power and perform a rectification on the AC power to generate a DC voltage signal

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 3

The driver module is connected to the rectifier module, and configured to generate a constant-current driving signal according to the DC voltage signal in a discontinuous conduction mode, and adjust an output duty cycle according to the constant-current driving signal to maintain a constant current of the constant-current drive signal

Methodology Applied
Scientific EffectPulse width modulation: Phase Modulation

Implementation Method 4

The electromagnetic suppression module is connected to the driver module, and configured to eliminate a clutter interference signal in the DC voltage signal to improve an electromagnetic performance of the circuit

Methodology Applied
Scientific EffectElectromagnetic filtering: Filter (electronic)

Data Source

PatentEP4037439B1Constant-current drive circuit, constant-current drive device and lamp
Publication Date: 2024.08.14 LEEDARSON GREEN LIGHTING
  • EP4037439B1 patent drawingFigure 1~2
  • EP4037439B1 patent drawingFigure 3~4
  • EP4037439B1 patent drawing

AI summary

The present application relates to the field of driving technology, and provides a constant-current drive circuit, a constant-current drive device, and a lamp. The AC power is connected via a rectifier module (10) and rectified by the rectifier module (10) to generate a DC voltage signal. An electrolytic capacitor (C3) is provided at an output end of the rectifier module (10) to improve an efficiency of circuit and to eliminate a stroboscopic phenomenon in the DC voltage signal. The driver module (20) is configured to generate a constant-current driving signal according to the DC voltage signal in the discontinuous conduction mode, and adjust an output duty cycle according to the constant-current driving signal to maintain a constant current of the constant-current driving signal. The electromagnetic suppression module (30) is configured to eliminate a clutter interference signal in the DC voltage signal to improve an electromagnetic performance of the circuit. Such that problems of higher driving cost and larger size of driving space caused by an additional de-stroboscopic circuit in the circuit can be solved.