LED Driver Achieves Electrolytic Capacitor-Less and Flicker-Free Operation with an Energy Buffer Unit

In this paper, a cycle-by-cycle energy buffering LED driver has been proposed to achieve electrolytic capacitor-less flicker-free operation. An energy buffering unit (EBU), with high voltage film capacitors being the energy storage device, is introduced in the design to buffer imbalanced energy in every switching cycle. The switching current can be controlled to meet high power factor correction and deliver DC LED output current at the same time. Compared to previous electrolytic capacitor-less designs, it can reduce circulating power and, therefore, also reduce power conversion loss. A 15W experimental prototype had been built and tested to verify the proposed LED driving method.