FAN7688 Advanced Pulse Frequency Modulated Controller Fairchild FAN7688 Advanced Pulse Frequency Modulated Controller offers best-in-class efficiency for isolated DC/DC converters. It's a controller for LLC resonant converters with Synchronous Rectification (SR) and employs a current mode control technique based on a charge control. The triangular waveform from the oscillator is combined with the integrated switch current information to determine the switching frequency. This provides a better control-to-output transfer function of the power stage simplifying the feedback loop design while allowing true input power limit capability.Learn More