The NCP1247 is a new fixed−frequency current−mode controller featuring the Dynamic Self−Supply. This 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 start−up, transients, latch, stand−by etc. This device contains a special HV detector which detect the application unplug from the AC input line and triggers the X2 discharge current. This HV structure allows the brown−out detection as well.

FEATUREs
• Fixed−Frequency Current−Mode Operation (65 kHz and 100 kHz frequency options)
• Frequency Foldback then Skip Mode for Maximized Performance in Light Load and Standby Conditions
• Timer−Based Overload Protection with Latched (Options A/C) or Auto−Recovery (Options B/D) Operation
• High−voltage Current Source with Brown−Out Detection and Dynamic Self−Supply, Simplifying the Design of the VCC Circuitry
• Frequency Modulation for Softened EMI Signature
• Adjustable Overpower Protection Dependant on the Bulk Voltage
• Latch−off Input Combined with the Overpower Protection Sensing Input
• VCC Operation up to 28 V, With Overvoltage Detection
• 500/800 mA Source/Sink Drive Peak Current Capability
• 10 ms Soft−Start
• Internal Thermal Shutdown
• No−Load Standby Power < 30 mW
• X2 Capacitor in EMI Filter Discharging Feature
• These Devices are Pb−Free and Halogen Free/BFR Free

Typical Applications
• AC−DC Adapters for Notebooks, LCD, and Printers
• Offline Battery Chargers
• Consumer Electronic Power Supplies
• Auxiliary/Housekeeping Power Supplies
• Offline Adapters for Notebooks