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This literature is subject to all applicable copyright laws and is not for resale in any manner.FAN7688 Advanced Secondary Side LLC Resonant Converter Controller with Synchronous Rectifier Control November 2015 FAN7688 Advanced Secondary Side LLC Resonant Converter Controller with Synchronous Rectifier Control Features Description Secondary Side PFM Controller for LLC Resonant The FAN7688 is an advanced Pulse Frequency Modulated (PFM) controller for LLC resonant converters Converter with Synchronous Rectifier Control with Synchronous Rectification (SR) that offers best in Charge Current Control for Better Transient class efficiency for isolated DC/DC converters. It Response and Easy Feedback Loop Design employs a current mode control technique based on a Adaptive Synchronous Rectification Control with charge control, where the triangular waveform from the oscillator is combined with the integrated switch current Dual Edge Tracking information to determine the switching frequency. This Closed Loop Soft-Start for Monotonic Rising Output provides a better control-to-output transfer function of the power stage simplifying the feedback loop design Wide Operating Frequency (39 kHz ~ 690 kHz) while allowing true input power limit capability. Closed- Green Functions to Improve Light-Load Efficiency loop soft-start prevents saturation of the error amplifier and allows monotonic rising of the output voltage Symmetric PWM Control at Light-Load to Limit the Switching Frequency while Reducing regardless of load condition. A dual edge tracking adaptive dead time control minimizes the body diode Switching Losses conduction time thus maximizing efficiency. Disabling SR at Light-Load Condition Protection Functions with Auto-Restart Over-Current Protection (OCP) Applications Output Short Protection (OSP) Desktop ATX, Desktop-Derived Server, Blade NON Zero-Voltage Switching Prevention (NZS) Server, and Telecom Power Supplies by Compensation Cutback (Frequency Shift) Intelligent 100 W-2 kW+ Off-Line Power Supplies Power Limit by Compensation Cutback High Efficiency Isolated DC-DC Converters (Frequency Shift) Large Screen Display Power Overload Protection (OLP) with Programmable Shutdown Delay Time Industrial Power Over-Temperature Protection (OTP) Programmable Dead Times for Primary Side Switches and Secondary Side Synchronous Rectifiers V Under-Voltage Lockout (UVLO) DD Wide Operating Temperature Range -40C to +125C Ordering Information Operating Part Number Package Packing Method Temperature Range FAN7688SJX -40 to 125C 16-Lead, Small-Outline Package Tape & Reel Note: 1. All packages are lead free per JEDEC: J-STD-020B standard. 2015 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN7688 Rev. 1.3