FSQ510: 700V Integrated Power Switch with Valley Switching control for 6Watt offline flyback converters

A Valley Switching Converter (VSC) generally shows lower EMI and higher power conversion efficiency than a conventional hard-switched converter with a fixed switching frequency. The FSQ510 (H or M) is an integrated valley switching pulse width modulation (VS-PWM) controller and SenseFET specifically designed for offline switch-mode power supplies (SMPS) for valley switching with minimal external components. The VS-PWM controller includes an integrated oscillator, under-voltage lockout (UVLO), 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 FSQ510 (H or M) can reduce total cost, component count, size and weight; while simultaneously increasing efficiency, productivity, and system reliability. This device provides a platform for cost-effective designs of a valley switching flyback converters.

Features

• Uses a LDMOS Integrated Power Switch
• Optimized for Valley Switching Converter (VSC)
• Low EMI through Variable Frequency Control and Inherent Frequency Modulation
• High Efficiency through Minimum Drain Voltage Switching
• Extended Valley Switching for Wide Load Ranges
• Small Frequency Variation for Wide Load Ranges
• Advanced Burst-Mode Operation for Low Standby Power Consumption
• Pulse-by-Pulse Current Limit
• Protection Functions: Overload Protection (OLP), Internal Thermal Shutdown (TSD) with Hysteresis
• Under Voltage Lockout (UVLO) with Hysteresis
• Internal Startup Circuit
• Internal High-Voltage SenseFET: 700V
• Built-in Soft Start: 5ms

Application Notes