Design and optimization of high-efficiency 1W 500V-12V isolated low-cost DC/DC converter

Conversion from high-input-voltage to low-output-voltage in low-power mode is challenging, especially with high-efficiency and small-size requirements. Standard Flyback solutions are not good enough for these applications. This works analyzes the design trends for a low-power Asymmetrical Half-Bridge Flyback, with special attention given to the power-stage and transformer design. A simplified model of the converter is built to compare a large number of solutions and to validate the design approach. Results from the model are analyzed, through the study of some key parameters and some interesting designs are identified. They show the benefits of this approach with respect to existing solutions, based on standard Flyback.