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Abstract
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One of the most efficient lighting technologies is based on light-emitting diodes (LEDs). Common LED
drivers with AC-input (50-60Hz) usually require a bulk electrolytic capacitor to decrease low-frequency ripple in the
output. However, the critical element that limits the lifespan of the LED driver is the electrolytic capacitor. An isolated
off-line LED driver is proposed in this paper, in which the required output capacitance is reduced so that the
electrolytic capacitor can be omitted from the driver structure. The driver’s configuration and controlling method
provide a high input power factor. Just a single switch and therefore a single controlling IC have been used in the
proposed structure. The input power factor correction is implemented utilizing a boost-based method, and a novel
structure is introduced for dc/dc conversion section. Power factor correction and dc/dc conversion are performed
employing a simplistic and single controlling system. The output current feeding the LEDs is a high frequency pulsating
current. Calculations, simulations and experimental waveforms of a laboratory prototype are presented to confirm the
validity of the proposed driver.
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