Application note for using Würth Elektronik optocouplers in flyback converters

This resource is particularly beneficial for those incorporating optocouplers to achieve galvanic isolation in the feedback path. Its applications span a broad range, from primary and auxiliary power supplies in household appliances and battery chargers for mobile devices to LED lighting solutions. Additionally, it offers guidance for developing power supplies for desktop and laptop computers, industrial applications, motor drive auxiliary supplies, and Power-over-Ethernet (PoE) systems.

The application note ANP113 delves into the intricacies of compensating the feedback loop in a current-controlled flyback converter equipped with an optocoupler, highlighting the critical consideration of the CTR (current transfer ratio) on the compensation circuit's control loop during the design process. It underscores the importance of accounting for optocoupler parameters and the solutions to potential design challenges. Furthermore, ANP113 includes the validation results of a 30-W flyback converter prototype, providing practical insights into the application of these principles.