Many T8 LED tubes are currently available in the market; however, the majority of commercial products are passive converters, so the lamp current is not well controlled. This paper presents a low voltage, current-fed Buck converter for a T8 LED tube application. A very simple control method with zero-crossing synchronization is proposed; the operation of the circuit is described, and the performance of prototype proves the concept. The current-fed Buck converter is compatible with most commercial electronic ballasts.