This application note details the design process for offline forward converters based on the FPS controller family. It explains that most FPS devices share a common pinout from pins 1 to 4, simplifying the integration of MOSFETs and PWM controllers into a single package.
The guide outlines a nine-step procedure for designing these power supplies. Key steps include defining system specifications (input voltage, frequency, output power), calculating input capacitance and DC bus voltage, selecting clamping methods (such as RCD or snubber circuits) to limit MOSFET stress, determining transformer winding ratios, and sizing the core area and wire gauge based on RMS current requirements. This manual is written in Chinese.
The recommended maximum duty cycle is 0.45 to prevent core saturation during reset.