●Fixed Frequency Current Mode Controller for Flyback Converters
●The NCP1237 is a new generation of the NCP12xx fixed−frequency current−mode controllers featuring Dynamic Self−Supply (DSS), pin−to−pin compatible with the previous generation.
●The DSS function greatly simplifies the design of the auxiliary supply and the VCCcapacitor by activating the internal startup current source to supply the controller during transients.
●Features
●•Timer−Based Transient Power and Overload Protections with Auto−Recovery (Option B) or Latched (Option A) Operation
●•High−Voltage Current Source with DSS with Built−in Brown−out and Line Overvoltage Protections
●•Fixed−Frequency Current−Mode Operation with Built−in Ramp Compensation
●•Frequency Jittering for a Reduced EMI Signature
●•Adjustable Overpower Compensation
●•Latch−off Input for Severe Fault Conditions, with Direct Connection of an NTC for Overtemperature Protection (OTP)
●•Protection Against Winding Short−Circuit
●•Frequency Foldback transitioning into Soft−Skip for Improved Performance in Standby
●•65 kHz Oscillator (100 kHz and 133 kHz Versions Available Upon Request)
●•VCCOperation up to 28 V
●•Increased Precision on Critical Parameters
●•±1.0 A Peak Drive Capability
●•4.0 ms Soft−Start
●•Internal Thermal Shutdown with Hysteresis
●•These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant
●Typical Applications
●•ac−dc Adapters for Notebooks, LCD, and Printers
●•Offline Battery Chargers
●•Consumer Electronic Power Supplies
●•Auxiliary/Housekeeping Power Supplies
