The NCP1339 is a highly integrated quasi−resonant flyback

controller capable of controlling rugged and high−performance

off−line power supplies as required by adapter applications. With an

integrated active X−cap discharge feature and power savings mode,

the NCP1339 can enable no−load power consumption below 10 mW

for 45 W notebook adapters.

The quasi−resonant current−mode flyback stage features a

proprietary valley−lockout circuitry, ensuring stable valley switching.

This system works down to the 6th valley and toggles to a frequency

foldback mode to eliminate switching losses. When the loop tends to

force below 25−kHz frequencies, the NCP1339 skips cycles to contain

the power delivery.

To help build rugged converters, the controller features several key

protective features: an internal brown−out, a non−dissipative Over Power

Protection for a constant maximum output current regardless of the

input voltage, a latched over−voltage protection through a dedicated pin.

Features

• High−voltage Current Source for Lossless Start−up Sequence

• X2 Capacitors Discharge Capability

• Power Savings Mode (PSM) for Extremely Low No−Load Power:

• Wide VCC Range from 10 V to 28 V

• Latching−off 28−V VCC Over−Voltage Protection

• Abnormal Overcurrent Fault Protection for Winding Short Circuit or Inductor Saturation Detection

• Integrated High−Voltage Startup Circuit with Brown−Out Detection

• Fault Input for Severe Fault Conditions, NTC Compatible for OTP

• Circuit Latching Off In Severe Fault Detection (OVP or OTP)

• Internal Temperature Shutdown

• Valley Switching Operation with Valley−Lockout for Noise−Free Operation

• Frequency Fold−back for Highest Performance in Standby Mode

• 25−kHz Clamp and Skip Mode

• Timer−Based Overload Protection (Latched or Auto−Recovery Options)

• Adjustable Overpower Protection

• 4−ms Soft−Start Timer

• ZCD Blanking Time to Ignore Leakage Ringing at Turn−Off:

3 us for C, D and E versions and 0.7 us for F, G, H, I and J versions

• Ready for High−Density QR design (F, G, H, I and J versions)

• These Devices are Pb−Free and are RoHS Compliant