onsemi (Ansemi)

SOT-23-6

taping

3000

The NCP1361 provides a novel solution aimed at achieving output power levels from a few watts to 20 W in general power supply flyback applications. Thanks to the new approach, the new controller eliminates the need for an auxiliary feedback circuit for constant current regulation, while achieving excellent line and load regulation using a conventional optocoupler and TL431 voltage reference. The NCP1361 operates in a valley-lock quasi-resonant peak current control mode at high loads to provide high energy efficiency. When auxiliary side power starts to disappear, the controller will automatically adjust the duty cycle, then at lower loads, the controller goes into pulse frequency modulation with a fixed peak current through valley switching detection. This technique allows output regulation to be maintained under small dummy loads. Valley lockout in the first 4 valleys prevents valley skipping operation, then valley switching at lower loads provides high energy efficiency.