Green-Mode Fairchild Power Switch (FPS) for Quasi-Resonant Operation - Low EMI and High Efficiency User Manual / Data Sheet
Summary
This Green-Mode Fairchild Power Switch is an optimized solution for designing high-efficiency Quasi-Resonant Converters (QRC). It significantly lowers EMI while maximizing performance in critical power applications, replacing complex discrete circuit components. This manual provides comprehensive documentation on its low-EMI operation, advanced protection features, and suitability for use across various modern devices, including LCD monitors and TV power supplies. It is an essential resource for electronics engineers developing reliable and cost-effective power conversion systems.
Page 1 Text Content
FSQ 0565R S/R reen-M ode Farichild Pow er Sw itch (FPS ) for Q uasi-R esonant O peration
December 2009
FSQ0565RS/RQ Green-Mode Fairchild Power Switch (FPS) for Quasi-Resonant Operation - Low EMI and High Efficiency Features Description Optimized for Quasi-Resonant Converters (QRC) A Quasi-Resonant Converter (QRC) generally shows
Low EMI through Variable Frequency Control and AVS lower EMI and higher power conversion efficiency than a
(Alternating Valley Switching) conventional hard-switched converter with a fixed
High-Efficiency through Minimum Voltage Switching switching frequency. The FSQ-series is an integrated Narrow Frequency Variation Range over Wide Load Pulse-Width Modulation (PWM) controller and and Input Voltage Variation Sense FET specifically designed for quasi-resonant Advanced Burst-Mode Operation for Low Standby operation and Alternating Valley Switching (AVS). The Power Consumption PWM controller includes an integrated fixed-frequency Simple Scheme for Sync Voltage Detection oscillator, Under-Voltage Lockout (UVLO), Leading- Edge Blanking (LEB), optimized gate driver, internal soft-
Pulse-by-Pulse Current Limit
start, temperature-compensated precise current sources
Various Protection Functions: Overload Protection
for a loop compensation, and self-protection circuitry.
(OLP), Over-Voltage Protection (OVP), Internal
Thermal Shutdown (TSD) with Hysteresis, Compared with a discrete MOSFET and PWM controller Output Short Protection (OSP) solution, the FSQ-series can reduce total cost, Under-Voltage Lockout (UVLO) with Hysteresis component count, size, and weight; while simultaneously increasing efficiency, productivity, and system reliability.
Internal Startup Circuit
This device provides a basic platform for cost-effective
Internal High-Voltage Sense FET (650V)
designs of quasi-resonant switching flyback converters.
Built-in Soft-Start (17.5ms)
Applications Power Supply for LCD TV and Monitor, VCR, SVR, STB, and DVD & DVD Recorder Adapter Related Resources Visit: http://www.fairchildsemi.com/apnotes/ for: AN-4134: Design Guidelines for Offline Forward Converters Using Fairchild Power Switch (FPS) AN-4137: Design Guidelines for Offline Flyback Converters Using Fairchild Power Switch (FPS) AN-4140: Transformer Design Consideration for Offline Flyback Converters Using Fairchild Power Switch (FPS) AN-4141: Troubleshooting and Design Tips for Fairchild Power Switch (FPS) Flyback Applications AN-4145: Electromagnetic Compatibility for Power Converters AN-4147: Design Guidelines for RCD Snubber of Flyback Converters AN-4148: Audible Noise Reduction Techniques for Fairchild Power Switch (FPS) Applications AN-4150: Design Guidelines for Flyback Converters Using FSQ-Series Fairchild Power Switch (FPS)
© 2 008 Fairchild Semiconductor Corporation www.fairchildsemi.com FSQ 0565RS/RQ Rev. 1.0.3
Page Summary Contents For Green-Mode Fairchild Power Switch (FPS) for Quasi-Resonant Operation - Low EMI and High Efficiency User Manual / Data Sheet
Manual Details
| Brand | Fairchild |
|---|---|
| Pages | 23 |
| File Size | 2.79 MB |
| Published | July 16, 2026 |
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Frequently Asked Questions
How does the FSQ-series improve power efficiency?
It achieves high efficiency through Minimum Voltage Switching and using its optimized design for Quasi-Resonant Converters (QRC).
What protection functions are integrated into this switch?
The series includes Overload Protection (OLP), Over-Voltage Protection (OVP), Thermal Shutdown (TSD), and Output Short Protection (OSP).
Where can I find detailed design guidelines for using this switch?
Fairchild provides specific Application Notes, such as AN-4150 for Flyback Converters, on their website.