ON Semiconductor NCP1343 Quasi-Resonant Flyback Controllers

ON Semiconductor NCP1343 Quasi-Resonant Flyback Controllers


ON Semiconductor NCP1343 Quasi-Resonant Flyback Controllers are ideal for designing high-performance off-line power converters. The NCP1343 features a proprietary valley-lockout circuitry, that ensures stable valley switching. This system works down to the 6th valley and transitions to frequency foldback mode to reduce switching losses. The NCP1343 enters quiet-skip mode as the load decreases to manage the power delivery while minimizing acoustic noise.


  • Integrated high-voltage startup circuit with brownout detection
  • Wide VCC range from 9V to 28V
  • 28V VCC overvoltage protection
  • Abnormal overcurrent fault protection for winding short circuit or saturation detection
  • Internal temperature shutdown
  • Valley switching operation with valley-lockout for noise-free operation
  • Frequency foldback with 25khz minimum frequency clamp for increased efficiency at light loads
  • Rapid frequency foldback for fast reduction of switching frequency at light loads
  • Skip mode with quiet-skip technology for highest performance during light loads
  • Minimized current consumption for no-load power below 30mw
  • Frequency jittering for reduced EMI signature
  • Latching or auto-recovery timer-based overload protection
  • Adjustable overpower protection (OPP)
  • Adjustable maximum frequency clamp
  • Ccm operation during power excursion mode (PEM)
  • Fault pin for severe fault conditions, NTC compatible for OTP

Block Diagram

more information: https://www.onsemi.com/products/power-management/ac-dc-controllers-regulators/offline-controllers/ncp1343

Mike is the founder and editor of Electronics-Lab.com, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)

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