This application note describes a detailed design strategy for higher-power conversion efficiency and better EMI using a Quasi-Resonant PWM controller compared to the conventional, hard-switched converter with a fixed switching frequency. Based on the proposed design guideline, a design example with detailed parameters demonstrates the performance of the controller.
The document describes the highly integrated FAN6300/A/H PWM controller, which enhances flyback converter performance. The FAN6300/A models are designed for Quasi-Resonant operation below 100kHz, while the FAN6300H is suitable for high-frequency operation around 190kHz. Key features include a built-in High Voltage startup circuit to reduce startup time and an internal valley voltage detector to ensure quasi-resonant operation across wide line voltages.
The maximum operating frequency for these models is below 100kHz.
The turn-on threshold is fixed at 16V and the turn-off threshold is fixed at 10V.