ON Semiconductor – NCP1129/26/24: High Voltage Switching Regulator for Offline SMPS

The NCP1129, NCP1126 and NCP1124 can deliver up to 25W, 15W and 12W respectively and each generate a jittered 65kHz or 100kHz switching frequency, resulting in marked improvements in electromagnetic interference (EMI) performance. They integrate a fixed frequency peak current mode controller with a low on-resistance high voltage, 650V MOSFET. The NCP112x devices all have a wide array of protective features including a 50ms timer-based auto-recovery short circuit protection function. Furthermore, short circuit fault conditions can be independently detected from the auxiliary winding voltage.


  • 650V avalanche rated MOSFET
  • Frequency foldback down to 26kHz and skip cycle in light load conditions
  • 50ms timer-based auto-recovery short circuit protection
  • Option for auto-recovery or latched short circuit protection
  • Less than 100mW stand-by power at high line
  • Fixed frequency 65kHz or 100kHz current mode control operation
  • Adjustable current limit with external resistor
  • Frequency jittering in normal and frequency foldback modes
  • Pb-free PDIP-7 packages
  • 10k MSRP: starting at $0.32 US