Description
A Quasi-Resonant Converter (QRC) 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 quasi-resonant operation and Alternating Valley Switching (AVS). The PWM controller includes an integrated fixed-frequency oscillator, Under-Voltage Lockout (UVLO), Leading-Edge Blanking (LEB), optimized gate driver, internal softstart, temperature-compensated precise current sources for a loop compensation, and self-protection circuitry.

Features
■ Optimized for Quasi-Resonant Converter (QRC)
■ Low EMI through Variable Frequency Control and AVS (Alternating Valley Switching)
■ 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
■ Simple Scheme for Sync Voltage Detection
■ Pulse-by-Pulse Current Limit
■ Various Protection functions: Overload Protection (OLP), Over-Voltage Protection (OVP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD) with Hysteresis, Output Short Protection (OSP)
■ Under-Voltage Lockout (UVLO) with Hysteresis
■ Internal Startup Circuit
■ Internal High-Voltage Sense FET (650V)
■ Built-in Soft-Start (17.5ms)

Applications
■ Power Supply for LCD TV and Monitor, VCR, SVR, STB, and DVD & DVD Recorder
■ Adapter