NCP1234: Controller, Fixed Frequency, Current Mode, for Flyback Converters

NCP1234 is a new fixed-frequency current-mode controller featuring Dynamic Self-Supply (DSS). This device is pin-to-pin compatible with the previous NCP12xx families.The DSS function greatly simplifies the design of the auxiliary supply and the VCC capacitor by activating the internal startup current source to supply the controller during transients. Due to frequency foldback, the controller exhibits excellent efficiency in light load condition while still achieving very low standby power consumption. Internal frequency jittering, ramp compensation, and a versatile latch input make this controller an excellent candidate for converters where component cost is the key constraint.It features a timer-based fault detection that ensures the detection of overload independently of an auxiliary winding, and an adjustable compensation to help keep the maximum power independent of the input voltage.

Features
  • Frequency Foldback then Skip Mode in light load and standby conditions
  • High voltage current source with brown-out detection and dynamic self-supply
  • Frequency Jittering
  • 4.0 ms Soft-Start
  • Adjustable Overpower Compensation
  • Latched / Autorecovery Timer-Based Overload Protection
Benefits
  • High efficiency in light and no load conditions
  • Directly powered from the high voltage rail with integrated brown-out sensing to detect low input voltage
  • Helps pass EMI requirements by spreading out the energy content of frequency peaks
  • Minimizes the stress on power components
  • Monitors the input voltage to limit the amount of power being delivered by the converter
  • Protects against overcurrent
Applications
  • Consumer Electronics Power Supplies
  • Auxiliary/Housekeeping power supplies
End Products
  • Notebooks
Package Drawings (1)
Document TitleDocument ID/SizeRevision
SOIC 7 CASE OUTLINE751U (62.0kB)E
Data Sheets (1)
Document TitleDocument ID/SizeRevisionRevision Date
Fixed Frequency Current Mode Controller for Flyback ConvertersNCP1234/D (225kB)2Jan, 2016
Order Information
ProductStatusCompliancePackageMSL*ContainerBudgetary Price/Unit
NCP1234AD100R2GActivePb-free Halide freeSOIC-7751U1Tape and Reel2500$0.32
NCP1234AD65R2GActivePb-free Halide freeSOIC-7751U1Tape and Reel2500$0.32
NCP1234BD100R2GActivePb-free Halide freeSOIC-7751U1Tape and Reel2500$0.32
NCP1234BD65R2GActivePb-free Halide freeSOIC-7751U1Tape and Reel2500$0.32
Specifications
ProductTopologyControl Modefsw Typ (kHz)Stand-by ModeUVLO (V)Short Circuit ProtectionLatchSoft StartVCC Max (V)Drive Cap. (mA)
NCP1234AD100R2GFlybackCurrent Mode100Yes9.5YesYesYes28500 / 500
NCP1234AD65R2GFlybackCurrent Mode65Yes9.5YesYesYes28500 / 500
NCP1234BD100R2GFlybackCurrent Mode65Yes9.5YesYesYes28500 / 500
NCP1234BD65R2GFlybackCurrent Mode65Yes9.5YesYesYes28500 / 500
Fixed Frequency Current Mode Controller for Flyback Converters (225kB) NCP1234
SOIC 7 CASE OUTLINE NCL30060
NCP1234