Transformerless LED Driver Circuit for Compact Lighting

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Solution Overview

Problem

Conventional lighting systems for LED tube lamps are bulky due to the weight and dimensions of transformers and suffer from reduced lifespan due to electrolytic capacitor issues in power factor correction circuits.

Innovation Solution

A compact lighting system with a rectifier circuit, voltage reducing circuit, dimmer circuit, and driver module that modulates pulsating direct current voltage to control light intensity without a transformer, eliminating the need for a power factor correction circuit and thus avoiding electrolytic capacitor issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a transformer is used in the driving circuit to reduce voltage, then voltage reduction is achieved, but the weight and dimensions of the system increase

Engineering Contradiction:

Improvevoltage reductionVSAvoidweight and dimensions

Core Design Contradiction:

PowerVSWeight of stationary object

Solution Approach 1:

The patent removes the transformer from the driving circuit entirely, extracting the bulky voltage reduction component and replacing it with a voltage reducing circuit that uses switching elements and inductors to achieve voltage reduction without the weight and size of a transformer

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electromagnetic transformer system with an electronic switching-based voltage reducing circuit, using semiconductor switching elements and control circuits to achieve the same voltage reduction function without mechanical or large electromagnetic components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If a power factor correction circuit with electrolytic capacitor is used, then power factor correction is achieved, but the lifespan is reduced due to electrolytic solution drying

Engineering Contradiction:

Improvepower factor correctionVSAvoidlifespan

Core Design Contradiction:

PowerVSDuration of action of stationary object

Solution Approach 1:

The patent removes the power factor correction circuit containing the electrolytic capacitor from the driving circuit, eliminating the source of the lifespan problem while maintaining the core LED driving functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent accepts the trade-off of not having power factor correction (which would require short-living electrolytic capacitors) and instead uses a simpler circuit design that prioritizes long lifespan over optimal power factor, replacing potentially failing components with more reliable alternatives

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Weight of stationary object

If a compact design without transformer is implemented, then weight and dimensions are reduced, but voltage reduction capability must be maintained

Engineering Contradiction:

Improveweight and dimensionsVSAvoidvoltage reduction capability

Core Design Contradiction:

Weight of stationary objectVSPower

Solution Approach 1:

The patent changes the operating parameters and topology of the voltage reducing circuit, using switching elements operated at high frequencies and controlled duty cycles to achieve efficient voltage reduction in a compact form factor without requiring large magnetic components

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

The solution results in a lightweight, reliable, and long-lasting lighting system with controlled light intensity, reducing weight and dimensions while preventing electrolytic capacitor drying, thereby extending the system's lifespan.

Implementation Method 1

a rectifier circuit operable to rectify an input alternating current signal and to output a pulsating direct current voltage

Methodology Applied

Scientific EffectRectification: Diode

Implementation Method 2

a voltage reducing circuit electrically coupled with the rectifier circuit and operable to reduce the voltage of the pulsating direct current voltage

Methodology Applied

Scientific EffectVoltage reduction:

Implementation Method 3

a driver module electrically coupled with the lighting appliance, the rectifier circuit and the dimmer circuit and operable to modulate a duty cycle of the pulsating direct current voltage based on the dimmer signal to generate a pulse width modulated signal that is provided to the lighting appliance for driving the lighting appliance to generate light

Methodology Applied

Scientific EffectPulse width modulation:

Implementation Method 4

a light emitting diode tube lamp having light emitting diodes D electrically connected in series

Methodology Applied

Scientific EffectLight emitting diode effect: Light Emitting Diode

Data Source

PatentUS9198249B1Lighting system including a driving device for driving a lighting appliance

Publication Date: 2015.11.24 HABITEX

AI summary

A driving device of a lighting system includes a rectifier circuit, a voltage reducing circuit, a dimmer circuit, and a driver module. The rectifier circuit outputs a pulsating direct current voltage. The voltage reducing circuit is operable to output a reduced direct current voltage associated with the pulsating direct current voltage. The dimmer circuit generates a dimmer signal based on detected occurrence of an interruption to the pulsating direct current voltage. Based on the dimmer signal, the driver module generates a pulse width modulated signal for driving a lighting appliance to generate light with an intensity corresponding to the dimmer signal.