Evaluation of a Low-Cost Permanent Emergency Lighting System Based on High-Efficiency LEDs

Evaluation on the Efficiency of Power LEDs Driven with Currents Typical to Switch Mode Power Supplies

“…But as white light emitting diodes (LEDs) are available since a few years, it can be predicted that they will be more and more employed for illumination purposes because of their high efficiency and very long life time [1,2,3]. However, due to their small dynamic resistance and a forward voltage of only a few volts it is not possible to drive the LEDs directly from the mains.…”

Introduction to LED Backlight Driving Techniques for Liquid Crystal Display Panels

“…The soft-switched DC-DC resonant converter includes power switches Q 1 and Q 2 , resonant inductor L r , resonant capacitor C r , transformer T 1 , rectifier diodes D f1 and D f2 , filter capacitor C f , and the LED arrays represented by an equivalent resistance R o . The characteristic impedance and the resonant frequency are respectively [18][19][20][21].…”

An Improved Non-isolated LED Converter with Power Factor Correction and Average Current Mode Control

“…The first stage is used to provide a stable voltage for the post stage with AC/DC conversion at the universal input voltage, while the post stage is used for the DC/DC conversion. Unlike conventional LED drivers, it could be applied to both low and high voltage cases, such as it is widely used in car applications because the car power supply voltage is easily changeable [13,14]. With the goal to achieve higher power factor and LED constant average current control, the Boost-Buck converter with higher power rating operating in continuous current conduction mode (CCM) with average current mode control (ACMC) is proposed through adding two control blocks: PFC control and ACMC block.…”