FAN301

FAN301 — PWM Controller for Low Standby Power Charger Applications July 2010 FAN301 PWM Controller for Low Standby Power Charger Applications Features ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ Ultra-Low Standby Power Under 20mW at 264VAC Constant-Current (CC) Control without SecondaryFeedback Circuitry Green Mode: PWM Frequency Linearly Decreasing Fixed PWM Frequency at 45kHz with Frequency Hopping to Solve EMI Problems High-Voltage Startup Low Operating Current: 3mA Peak-Current-Mode Control in CV Mode Cycle-by-Cycle Current Limiting VDD Over-Voltage Protection (Auto-Restart) VDD Under-Voltage Lockout (UVLO) Gate Output Maximum Voltage Clamped at 15V Fixed Over-Temperature Protection (Auto-Restart) Description This highly integrated PWM controller, FAN301, provides features to enhance the performance of lowpower flyback converters. The proprietary topology enables simplified circuit design for battery charger applications. A low-cost, smaller, and lighter charger is the result, compared to a conventional design or a linear transformer. To minimize standby power consumption, a proprietary green-mode function provides off-time modulation to linearly decrease PWM frequency under light-load conditions. This green mode assists the power supply in meeting power conservation requirements. By using FAN301, a charger can be implemented with fewer external components and minimized cost. A typical output CV/CC characteristic envelope is shown in Figure 1. Vo Maximum Typical Minimum Applications ƒ ƒ ...