FAN7688 Advanced Secondary Side LLC Resonant Converter Controller The FAN7688 is an advanced pulse frequency modulation (PFM) controller for LLC resonant converters with synchronous rectification (SR) that provides best-in-class efficiency for isolated DC/DC converters. It employs a charge control based current mode control technique in which a triangular waveform from an oscillator is combined with integrated switch current information to determine the switching frequency. This provides better control of the power stage to the output transfer function, which simplifies feedback loop design while allowing true input power limiting capability. Closed-loop soft-start prevents error amplifier saturation and allows the output voltage to rise monotonically regardless of load conditions. Dual edge tracking adaptive dead-time control minimizes body diode conduction time to maximize efficiency.

Application:

Desktop ATX, desktop derivatives, blade servers, and telecom power supplies

Intelligent 100W-2kW+ offline power supply

High Efficiency Isolated DC-DC Converter

Large screen display power

Industrial power