FAN302UL: Primary-Side-Regulation PWM Controller

This highly integrated PWM controller provides several features to enhance the performance of flyback converters. The constant-current-control, proprietary topology enables simplified designs without secondary feedback circuitry for battery-charger applications.

A proprietary Burst-Mode function with low operation current minimizes standby power consumption.

The FAN302UL controller also provides several protections. Cycle-by-cycle current limiting ensures the fixed peak current limit level, even if a short circuit occurs. The gate output is clamped at 15V to protect the power MOS from high gate-source voltage conditions. If either VS OVP or internal OTP is triggered, the circuit enters Latch Mode until AC power is removed.

Using FAN302UL, a charger can be implemented with few external components and minimized cost, compared to a conventional design or a linear transformer.

Features

• Ultra-Low Standby Power: Under 20mW at 264V_AC
• Constant-Current (CC) Control without Secondary-Feedback Circuitry
• Fixed PWM Frequency at 140kHz with Frequency Hopping to Solve EMI Problems
• High-Voltage Startup
• Low Operating Current: 3.5mA
• Peak-Current-Mode Control in CV Regulation
• Cycle-by-Cycle Current Limiting
• V_DD Over-Voltage Protection (Auto-Restart)
• VS Over-Voltage Protection (Latch Mode)
• VDD Under-Voltage Lockout (UVLO)
• Gate Output Maximum Voltage Clamped at 15V
• Fixed Over-Temperature Protection (Latch Mode)
• Available in an 8-Lead SOIC Package

Application Notes