Green-Mode PWM Controller for Flyback Converter, Programmable Frequency 50KHz ~ 80KHz

This highly integrated PWM controller provides several special enhancements designed to meet the low standby-power needs of low-power SMPS. To minimize standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load conditions. This green-mode function enables the power supply to meet even the strictest power conservation requirements. The BiCMOS fabrication process enables reducing the start-up current to 9uA, and the operating current to 3mA. To further improve power conservation, a large start-up resistance can be used. Built-in synchronized slope compensation ensures the stability of peak current mode control. Proprietary internal compensation provides a constant output power limit over a universal AC input range (90 VAC to 264 VAC). Pulse-by-pulse current limiting ensures safe operation even during short-circuits. To protect the external power MOSFET from being damaged by supply over voltage, the SG6859A’s output driver is clamped at 17 V. SG6859A controllers can be used to improve the performance and reduce the production cost of power supplies. The best choice for replacing linear and RCC-mode power adapters, The SG6859A is available in 8-pin DIP and 6-pin SOT-26 packages.