Description A Valley Switching Converter generally shows lower EMI and higher power conversion efficiency than a conventional hard-switched converter with a fixed switching frequency. The FSQ-series is an integrated Pulse-Width Modulation (PWM) controller and SenseFET specifically designed for valley switching operation with minimal external components. The PWM controller includes an integrated fixed-frequency oscillator, under-voltage lockout, Leading-Edge Blanking (LEB), optimized gate driver, internal soft-start, temperature-compensated precise current sources for loop compensation, and self-protection circuitry. Features ■ Optimized for Valley Switching Converter (VSC) ■ Low EMI through Variable Frequency Control and Inherent Frequency Modulation ■ High Efficiency through Minimum Voltage Switching ■ Narrow Frequency Variation Range Over Wide Load and Input Voltage Variation ■ Advanced Burst-Mode Operation for Low Standby Power Consumption ■ Pulse-by-Pulse Current Limit ■ Protection Functions: Overload Protection (OLP), Over-Voltage Protection (OVP), Abnormal OverCurrent Protection (AOCP), Internal Thermal Shutdown (TSD) ■ Under-Voltage Lockout (UVLO) with Hysteresis ■ Internal Startup Circuit ■ Internal High-Voltage SenseFET: 650V ■ Built-in Soft-Start: 15ms Applications ■ Power Supplies for DVP Player, DVD Recorder, Set-Top Box ■ Adapter ■ Auxiliary Power Supply for PC, LCD TV, and PDP TV
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