Author: Zhang, Shijian
Title: Electrolytic capacitor-less LED drivers
Degree: M.Sc.
Year: 2013
Subject: Light emitting diodes.
Electronic circuit design.
Hong Kong Polytechnic University -- Dissertations
Department: Faculty of Engineering
Pages: vii, 50 leaves : ill. ; 30 cm.
Language: English
Abstract: Light-emitting-diode (LED) lamps are commonly used in our life today because their environmentally friendly, energy-saving, long lifetime and secure. LED drivers are the key to ensure the quality and lifetime of the LED lighting systems. When the LED drivers utilize the commercial ac voltage source, the function of power factor correction should be realized to achieve a high power factor. In order to balance the difference between the instantaneous input and output power, a large storage capacitor is required. Capacitor is an important component to affect the lifetime of LED drivers. However, the lifetime of electrolytic capacitor is much lower than the lifetime of LED driver, so electrolytic-less capacitor is proposed. Some electrolytic capacitor-less LED drivers are proposed to do a comparison which make us understand LED drivers better. One is the buck circuit, the output average current is equal to the current of inductance, so the output current is a triangular wave. The other one is flyback circuit, an input 2.5V is compared with the output voltage and current, optical feedback is used to control the primary duty cycle to make the both sides of amplifier output voltage steady. These circuits are the main content.
Rights: All rights reserved
Access: restricted access

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