FSQ0365_07 Datasheet, PDF (1/24 Pages) Fairchild Semiconductor – Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

May 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
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
„ Various 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 Start-up Circuit
„ Internal High-Voltage SenseFET (650V)
„ Built-in Soft-Start (15ms)
Applications
„ Power Supply for DVP Player and 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
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 cost-
effective designs of valley switching fly-back converters.
Related Application Notes
„ AN-4137, AN-4141, AN-4147, AN-4150 (Flyback)
„ AN-4134 (Forward)
FPS^TM is a trademark of Fairchild Semiconductor Corporation.
© 2006 Fairchild Semiconductor Corporation
FSQ0365, FSQ0265, FSQ0165, FSQ321, FSQ311 Rev. 1.0.4
www.fairchildsemi.com