A Novel Wall-Switched Step-Dimming Concept in LED Lighting Systems Using PFC Zeta Converter

This paper presents the design, simulation, and implementation of a non-isolated discontinuous conduction mode operated Zeta-converter-based light-emitting diode (LED) driver with the novel wall-switched step-dimming concept to achieve power quality improvement at universal ac mains. The power-factor-corrected Zeta converter maintains constant output current to an LED load of 26 W and conserves the power quality requirements as per IEC 61000-3-2 for class C equipment with high efficiency. Moreover, to obtain cost benefit and size reduction, this converter utilizes reduced control circuitry for general-purpose LED lighting solutions. A cost-effective single-level dimming concept is implemented with current injection technique using a Zeta converter. A prototype is developed using AP1682, which utilizes pulse frequency modulation technique to regulate the output current for improving the input power factor and low total harmonic distortion (THD) of the input current. At full load and rated voltage of 220 V, the measured input power factor is 0.993 and current THD is 2.81% with an efficiency of 90.51%.