Description

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 an 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

Applications

■ Auxiliary Power Supplies for LCD TV, LCD Monitor, Personal Computer, and White Goods