Evaluation of Low-Profile Offline Drivers Devised to Supply Power to 10W OLED Panels

This work presents a study concerning ac-to-dc drivers intended for indoor lighting OLED panels. The first topology, perhaps the most intuitive, consists on a two-stage ac-to-dc converter topology. Among the many possibilities, the paper begins comparing two different configurations: a buck-boost/buck alternative and the buck/buck option. Despite presenting slightly different behaviors, the first stage in both arrangements operates in discontinuous inductor current mode (DCM), featuring a self-power-factor correction (self PFC) ability and is also able to control the intermediate bus voltage. On the other hand, the second stage controls the current peak to protect the panel against over-current and perform a pulse width modulation strategy to provide dimming capability to the driver. A further topology is briefly described, consisting on a buck resonant ac-to-dc converter. Finally, the text presents a discussion about the practical driver implementation and the design-oriented to a low-profile feature by using planar inductors and GaN high electron mobility transistors.