The FAN352AP is a highly integrated Quasi-Resonant (QR) Flyback PWM controller from Fairchild Semiconductor (now ON Semiconductor). It's designed for high-performance offline power supplies, offering high efficiency, low standby power consumption, and comprehensive protection features.

Applications

• AC-DC power adapters for laptops, mobile devices, and other portable electronics
• Open-frame power supplies for TVs, monitors, and set-top boxes
• Auxiliary power supplies in larger systems
• LED lighting power supplies

Features

• Quasi-Resonant (QR) operation: Improves efficiency and reduces EMI.
• Valley switching: Minimizes switching losses.
• Low standby power consumption: Meets stringent energy efficiency requirements.
• Built-in soft-start: Reduces stress on components during startup.
• Over-voltage protection (OVP): Protects the power supply from excessive output voltage.
• Over-current protection (OCP): Prevents damage from excessive current flow.
• Over-temperature protection (OTP): Shuts down the device in case of overheating.
• Under-voltage lockout (UVLO): Ensures proper operation during low voltage conditions.
• Frequency foldback: Improves efficiency at light loads.

Benefits

• High Efficiency: Minimizes power losses and reduces heat generation.
• Reduced EMI: QR operation reduces electromagnetic interference.
• Low Standby Power Consumption: Meets energy efficiency standards like Energy Star and EuP Lot 6.
• Improved Reliability: Robust protection features ensure reliable operation.
• Simplified Design: Integrated features simplify the design process.

Additional Details

The FAN352AP operates by detecting the valley of the drain-source voltage of the MOSFET and turning on the MOSFET at that point. This minimizes switching losses and improves efficiency. The frequency foldback feature reduces the switching frequency at light loads, further improving efficiency. The device incorporates comprehensive protection features, including over-voltage protection, over-current protection, and over-temperature protection, ensuring reliable operation in various operating conditions.

The FAN352AP is typically available in a DIP or SMD package. The device is designed to operate over a wide input voltage range and is suitable for various power supply applications. The integrated soft-start feature limits the inrush current during startup, preventing stress on the power supply components.