NCP1342 Quasi-Resonant Flyback Controller with Val

By ON Semiconductor 222

NCP1342 Quasi-Resonant Flyback Controller with Val

ON Semiconductor's NCP1342 is a highly integrated quasi-resonant flyback controller suitable for designing high-performance off-line power converters. With an integrated active X2 capacitor discharge feature, the NCP1342 can enable no-load power consumption below 30 mW. Featuring proprietary valley-lockout circuitry, ensuring stable valley switching, this system works down to the 6th valley and transitions to frequency foldback mode to reduce switching losses. As the load decreases further, the NCP1342 enters quiet-skip mode to manage the power delivery while minimizing acoustic noise. To ensure light load performance with high-frequency designs, the NCP1342 incorporates minimum peak current modulation (MPCM) to reduce the switching frequency quickly. To help ensure converter ruggedness, the NCP1342 implements several key protective features such as internal brownout detection, a non-dissipative over-power protection (OPP) for constant maximum output power regardless of input voltage, a latched overvoltage and NTC-ready over temperature protection through a dedicated pin, and line removal detection to safely discharge the X2 capacitors when the AC line is removed.

  • Minimum peak current modulation (MPCM) for rapid frequency foldback (RFF)
  • QR frequency jittering
  • Quiet-skip technology
  • Integrated HV startup with brownout protection
  • Valley switching operation with valley lockout
  • Integrated X2 capacitor discharge capability
  • NTC compatible fault pin
  • High drive capability: -500 mA / +800 mA
  • Latch input for OVP and OTP implementation
  • Fast reduction of switching frequency for improved light load efficiency
  • Reduces EMI signature
  • Ensures operation outside audible range
  • Provides an efficient power-on source and protects against drops in input mains voltage
  • Maximizes the efficiency over the entire power range
  • Eliminates the need for an X2 resistor
  • Extra protection against high-temperature or other fault conditions
  • Enables faster switching of primary-side MOSFET
  • Simple implementation of required protection functions
  • Medium- or high-power AC/DC adapters
  • Ultra high-density AC/DC adapters
  • USB-PD compliant
  • Notebook adapters
  • Flat TV SMPS
  • Computer power supplies
  • Phone and tablet adapters


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