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