Onsemi NCP1379

Description

The NCP1379 hosts a high−performance circuitry aimed topowering quasi−resonant converters. Capitalizing on a proprietaryvalley−lockout system, the controller shifts gears and reduces theswitching frequency as the power loading becomes lighter. Thisresults in a stable operation despite switching events always occurringin the drain−source valley. This system works down to the 4th valleyand toggles to a variable frequency mode beyond, ensuring anexcellent standby power performance.The controller includes an Over Power Protection circuit whichclamps the delivered power at high−line. Safety−wise, a fixed internaltimer relies on the feedback voltage to detect a fault. Once the timerelapses, the controller stops and enters auto−recovery mode, ensuringa low duty−cycle burst operation. To further improve the safety of thepower supply, the NCP1379 features a pin to implement a combinedbrown−out/overvoltage protection.Particularly well suited for TVs power supply applications, thecontroller features a low startup voltage allowing the use of anauxiliary power supply to power the device.

Features

• Quasi−Resonant Peak Current−Mode Control Operation
• Valley Switching Operation with Valley−Lockout for Noise−ImmuneOperation
• Frequency Foldback at Light Load to Improve the Light LoadEfficiency
• Adjustable Over Power Protection
• Auto−Recovery Output Short−Circuit Protection
• Fixed Internal 80 ms Timer for Short−Circuit Protection
• Combined Overvoltage Protection and Brown−out
• +500 mA / −800 mA Peak Current Source/Sink Capability
• Internal Temperature Shutdown
• Direct Optocoupler Connection
• Low VCC(on) Allowing to Use a Standby Power Supply to Power theDevice
• Extremely Low No−Load Standby Power
• SO8 Package
• These Devices are Pb−Free and are RoHS Compliant

Typical applications

• Offline Adapters for Notebooks
• High Power ac−dc Converters for TVs, Set−Top Boxes etc.

More information

• Datasheet
• IC product information