The FSQ100RNA is a highly integrated power switch from Fairchild Semiconductor (now ON Semiconductor), part of their Power Switch (FPS™) family, designed for offline power supply applications using a Quasi-Resonant (QR) flyback converter topology. This device incorporates a SenseFET and a current mode PWM controller in a single package, minimizing external components and simplifying power supply designs while achieving high efficiency and low EMI.

Applications:

• Power adapters for mobile devices and laptops
• Auxiliary power supplies in consumer electronics
• Standby power supplies
• LED lighting power supplies
• Industrial power supplies

Features:

• Integrated SenseFET and QR PWM controller
• Low startup current
• Zero voltage switching (ZVS) operation in QR mode
• Built-in soft-start function
• Frequency hopping for improved EMI performance
• Pulse-by-pulse current limiting
• Overvoltage protection (OVP)
• Overload protection (OLP)
• Thermal shutdown function (TSD)
• Under-voltage lockout (UVLO)

Benefits:

• High efficiency due to QR operation and integrated design
• Reduced component count simplifies design and lowers BOM cost
• Enhanced reliability with built-in protection features
• Lower EMI emissions due to frequency hopping and QR operation
• Robust performance under various operating conditions
• Simplified PCB layout
• Faster time to market

Additional Details:

The FSQ100RNA utilizes a Quasi-Resonant (QR) flyback converter topology, which minimizes switching losses by turning on the MOSFET at zero voltage, resulting in higher efficiency compared to traditional hard-switching converters. The integrated SenseFET offers excellent avalanche ruggedness, ensuring reliable operation even under transient conditions. The soft-start function minimizes stress on the power components during startup, further enhancing reliability. The frequency hopping feature reduces EMI emissions, simplifying compliance with regulatory requirements. The device is typically packaged in a TO-220F or similar package.

This power switch is designed to meet stringent energy efficiency requirements and safety standards. It is a suitable choice for applications where high efficiency, low EMI, and robust protection are essential.