Onsemi NCP1366 | Demoboard NCP1366

Description

The NCP1361/66 offers a new solution targeting output power levels from a few watts up to 20 W in a universal−mains flyback application. Due to a novel method this new controller offers a primary−side constant current control, saving secondary−side components to perform current regulation. The NCP1361/66 operates in valley−lockout quasi−resonant peak current mode control mode at nominal load to provide high efficiency. When the secondary−side power starts diminishing, the switching frequency naturally increases until a voltage−controlled oscillator (VCO) takes the lead, synchronizing the MOSFET turn−on in a drain−source voltage valley. The frequency is thus reduced by stepping into successive valleys until the number 4 is reached. Beyond this point, the frequency is linearly decreased in valley−switching mode until a minimum is hit. Valley lockout during the first four drain−source valleys prevents erratic discrete jumps and provides good efficiency in lighter load situations.

Features

• ±10% Current Regulation
• 560 V Startup Current Source
• No Frequency Clamp, 80 or 110 kHz Maximum Switching Frequency Options
• Quasi−Resonant Operation with Valley Switching Operation
• Fixed Peak Current & Deep Frequency Foldback @Light Load Operation.
• External Constant Voltage Feedback Adjustment
• Cycle by Cycle Peak Current Limit
• Built−In Soft−Start
• Over & Under Output Voltage Protection
• Wide Operation VCC Range (up to 28 V)
• Low Start−up Current (2.5 A typ.) with NCP1361
• Clamped Gate−drive Output for MOSFET
• CS & Vs/ZCD pin Short and Open Protection
• Internal Temperature Shutdown
• Less than 30 mW No−Load Performance at High Line with NCP1366 Version
• These are Pb−Free Devices

Typical applications

• Low power ac−dc Adapters for Chargers.
• Ac−dc USB chargers for Cell Phones, Tablets and cameras

More information

• Datasheet
• IC product information