FEBFAN7688-I00250A-GEVB:LLC Resonant, 250 W, 400 V to 12.5 V Converter, Evaluation Board

Evaluation/Development Tool Description

The FEBFAN7688-I00250A-GEVB is a secondary-side, LLC resonant, Pulse Frequency Modulated (PFM) controller with dedicated Synchronous Rectification (SR) gate drive, offering best in class efficiency for isolated DC/DC converters. The primary resonant current is sensed and integrated to employ a type of peak current mode control known as charge control. The integrated resonant current is combined with a triangular waveform generated from an internal oscillator to determine the switching frequency. This provides a better control-to-output transfer function of the power stage making the feedback loop design easy and allows true input power limit capability. The FAN7688 also incorporates a closed loop soft-start function that uses an adaptive soft-start current to prevent saturation of the error amplifier which allows monotonic startup of the output voltage independent of load current. A dual edge tracking, adaptive SR drive technique minimizes body-diode conduction of the SR MOSFETs thereby maximizing overall efficiency.

Technical Documents

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