DESCRIPTION
This highly integrated PWM controller provides several features to enhance the performance of low-power flyback converters. To minimize standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load and zero-load conditions. This green-mode function enables the power supply to meet international power conservation requirements. The supply voltage, VDD, is also used for feedback compensation, to regulate the output voltage without requiring a conventional TL431 and a photo-coupler. The typical start-up current is only 8µA, while the typical operating current can be as low as 3.6mA. A large start-up resistance could be used to achieve even higher power conversion efficiency.

FEATURES
■ Linearly decreasing PWM frequency
■ Green-mode under light-load and zero-load conditions
■ Constant voltage (CV) and constant current (CC)
■ No secondary feedback
■ Low start-up current (8µA)
■ Low operating current (3.6mA)
■ Leading-edge blanking
■ Constant power limit
■ Universal AC input range
■ Synchronized slope compensation
■ 140°C OTP sensor with hysteresis
■ VDD over-voltage clamping
■ Cycle-by-cycle current limiting
■ Under-voltage lockout (UVLO)
■ Fixed PWM frequency with hopping
■ Gate output maximum voltage clamped at 17V
■ Small SOT-26 package

APPLICATIONS
Low-power flyback power converters, such as:
■ Battery chargers for cellular phones, cordless phones, PDAs, digital cameras, and power tools
■ Power adapters for ink jet printers, video game consoles, and portable audio players
■ Open-frame SMPS for TV/DVD standby and other auxiliary supplies, home appliances, consumer electronics, and PC 5V standby-power
■ Replacements for linear transformers and RCC SMPS