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The LM5157x/LM5158x device is a wide-input range, non-synchronous converter with an integrated power MOSFET. The commonly supported configurations include Boost, Flyback and SEPIC topologies. This report focuses on designing the LM5157x/LM5158x as a primary side regulated (PSR) flyback converter. The design procedure is generic on selecting suitable components of the PSR flyback converter for the given application specification. The LM5175EVM-FLY evaluation module is used as the example to illustrate the design procedure, and the circuit performance results are also presented in the LM5157EVM-FLY User's Guide. For typical applications the LM5157/58 Flyback Controller Quick Start Calculator can also be used to efficiently complete the calculations described in this report.