Q0165R

FSQ0365, FSQ0265, FSQ0165, FSQ321, FSQ311 — Green Mode Fairchild Power Switch (FPS™) September 2007 FSQ0365, FSQ0265, FSQ0165, FSQ321, FSQ311 Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter - Low EMI and High Efficiency Features „ Optimized for Valley Switching (VSC) „ Low EMI through Variable Frequency Control and 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. Compared with discrete MOSFET and PWM controller solutions, the FSQ-series reduces total cost, component count, size and weight; while simultaneously increasing efficiency, productivity, and system reliability. This device provides a basic platform that is well suited for costeffective designs of valley switching fly-back converters. Inherent Frequency Modulation „ High-Efficiency through Minimum Voltage Switching „ Narrow Frequency Variation Range over Wide Load and Input Voltage Variation „ Advanced Burst-Mode Operation fo...