Dual-output flyback driver topologies for tunable white LED lighting applications

Light-Emitting Diode (LED) module fabricated for tunable white lighting constitutes a cool-white LED array and a warm-white LED array. To drive these two arrays independently by pulse-width-modulation principle, a dual-output LED driver is necessary. In this study, two prospective dual-output versions of the conventional flyback driver circuit are proposed, viz. (1) parallel load branch (PLB) driver and (2) center-tapped transformer (CTT) driver. The design parameters of these drivers are estimated based on the exponential LED model and the radiation blending principle. The designed drivers are then simulated and evaluated in three operating modes. Both the drivers display satisfactory performance in terms of efficiency, power factor, brightness and color control accuracies. However, the performance of the CTT driver is relatively better than the PLB driver.