FSQ321 Datasheet | Fairchild Semiconductor

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 Sense FET: 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 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 Sense FET specifically designed for valley switching operation with minimal external ponents. The PWM controller includes an integrated fixed-frequency oscillator, under-voltage lockout, Leading-Edge Blanking (LEB), optimized gate driver, internal soft-start, temperature-pensated precise current sources for loop pensation, and self-protection circuitry. pared with discrete MOSFET and PWM controller solutions, the FSQ-series reduces total cost, ponent count, size and weight; while simultaneously increasing efficiency, productivity, and system reliability. This device provides a basic platform for cost-effective designs of valley switching fly-back converters. Related Application Notes - AN-4137 - Design Guidelines for Offline Flyback Converters Using Fairchild Power Switch (FPS™) - AN-4141 - Troubleshooting and Design Tips for Fairchild Power Switch (FPS™) Flyback Applications - AN-4147 - Design Guidelines for RCD Snubber of Flyback...