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