Efficiency characterization and optimization in flyback DC-DC converters

This paper presents efficiency characterization and optimization in conventional flyback DC-DC converters over wide ranges of operating conditions based on power loss modeling and multi-variable non-linear constrained optimization over design parameters and controller parameters. A valley switching technique is applied to reduce MOSFET turn-on switching loss in discontinuous conduction mode (DCM). An optimization procedure is formulated to minimize power loss weighted over a range of operating points, under a cost constraint. Experimental results with a 65 W flyback prototype demonstrate that combined design-time optimization, and controller optimization can lead to significant efficiency improvements.