FSQ321 Datasheet PDF - Fairchild

●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 Over Current 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