The NCP1365 offer a new solution targeting output power levels from a few watts up to 20 W in a universal-mains flyback application.Thanks to a novel method this new controller eliminates the need for a secondary feedback circuitry (typically an opto-coupler and TL431 reference) while achieving excellent line and load regulation.The NCP1365 operates in valley lockout quasi-resonant peak current mode control mode at high load to provide high efficiency. When the power on the secondary side starts to diminish, the controller automatically adjusts the duty-cycle then at lower load the controller enters in pulse frequency modulation at fixed peak current with a valley switching detection. This technique allows keeping the output regulation with tiny dummy load. Valley lockout at the first 4 valleys prevent valley jumping operation and then a valley switching at lower load provides high efficiency.

• No frequency clamp, 80 or 110 kHz Maximum Switching Frequency
• Quasi-Resonant with Valley Switching Operation
• 560-V Startup Current Source
• Fixed Peak Current & Deep frequency foldback @ light load operation
• Cycle by Cycle peak current limit
• Wide Operation VCC range (up to 28 V)
• Internal Temperature Shutdown
• CS & Vs/ZCD pin Short and Open Protection
• Constant Current Primary-side feedback eliminates secondary controller
• ±10% Current Regulation
• Build-in soft-sart
• Low Start-up current (2.5 μA typ.)
• Clamped Gate-drive Output for Mosfet
• Less than 10 mW No-Load Performance