The NCP1360/65 offers a new solution targeting output power

levels from a few watts up to 20 W in a universal?mains flyback

application. Thanks to a novel method this new controller saves the

secondary feedback circuitry (opto?coupler and TL431 reference)

while achieving excellent line and load regulation.

The NCP1360/65 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. This technique keeps the output in

regulation with the tiniest dummy load. Valley lockout during the first

four drain?source valleys prevents erratic discrete jumps and provides

good efficiency in lighter load situations.

Features

? Primary?Side Feedback Eliminates Opto?coupler and TL431

Reference

? ±5 Voltage Regulation

? ±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

? Build?In Soft?Start

? Over & Under Output Voltage Protection

? Cable Drop Compensation (None, 150 mV, 300 mV or 450 mV

Option)

? Wide Operation VCC Range (up to 28 V)

? Low Start?up Current (2.5 A typ.) with

NCP1360

? Clamped Gate?drive Output for MOSFET

? CS & Vs/ZCD pin Short and Open

Protection

? Internal Temperature Shutdown

? Less than 10 mW No?Load Performance

at High Line with NCP1365 Version

? Less than 30 mW No?Load Performance

at High Line with NCP1360 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