Improved efficiency coupled inductor-buck AC-DC light emitting diode (LED) driver

This work proposes coupled inductor-buck (CI-B) power factor correction (PFC) LED driver. As compared with conventional buck converters, the proposed CI-B PFC converter has several advantages such as; high step-down conversion, reduced total harmonic distortion (THD), increased efficiency, achieves high power factor (PF), reduced current/voltage stress of switch/diode, and effective switch utilization factor. The proposed converter is designed to operate in discontinuous current mode (DCM) to achieve high power factor (PF) and low THD to comply IEC 61000-3-2 class C standards. In addition, a simple one-loop voltage mode controller (VMC) is implemented to achieve the desired regulated output voltage. A proto-type of 16 Watt converter is built and experimental validations are presented.