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NCP1249AD65R2G

High-Voltage Current-Mode PWM Controller Featuring Peak Power Excursion and Extremely Low Stand-by Power Consumption

ON Semiconductor 

NCP1249A, NCP1249B

High-Voltage Current-Mode

PWM Controller Featuring

Peak Power Excursion and

Extremely Low Stand-by

Power Consumption

http://onsemi.com

The NCP1249 is a highly integrated high−voltage PWM controller

capable of delivering a rugged and high performance offline power

supply with extremely low no−load consumption. With a supply range

up to 30 V, the controller hosts a jittered 65−kHz switching circuitry

operated in peak current mode control. When the power on the

secondary side starts to decrease, the controller automatically folds

back its switching frequency down to a minimum level of 26 kHz. As

the power further goes down, the part enters skip cycle while freezing

the peak current setpoint.

To help build rugged converters, the controller features several key

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

Power Protection for a constant maximum output current regardless of

the input voltage and two latched over voltage protection inputs −

either through a dedicated pin or via the VCC input.

The controller architecture is arranged to authorize a transient peak

power excursion when the peak current hits the limit. At this point, the

switching frequency is increased from 65 kHz to 130 kHz until the

peak requirement disappears. The timer duration is then modulated as

the converter crosses a peak power excursion mode (long) or

undergoes a short circuit (short).

MARKING DIAGRAM

9

1

SOIC−9 NB

D SUFFIX

CASE 751BP

9

NCP1249x65

ALYW

G

1

NCP1249x65 = Specific Device Code

x

= A or B

A

= Assembly Location

L

= Wafer Lot

Y

= Year

W

= Work Week

G

= Pb−Free Package

PIN CONNECTIONS

1

X2

HV

REM

FB

CS

OPP/LATCH

VCC

DRV

GND

(Top View)

Features

• High−voltage Current Source for Lossless Start−up

Sequence

• Remote Input for Standby Operation Control

• Automatic and Lossless X2 Capacitors Discharge

Function

• 65−kHz Fixed−frequency Current−mode Control

Operation with 130−kHz Excursion

• Internal and Adjustable Over Power Protection (OPP)

Circuit

• Internal Brown−Out Protection Circuit

• Frequency Foldback down to 26 kHz and Skip−cycle in

Light Load Conditions

• Adjustable Ramp Compensation

• Internally Fixed 4−ms Soft−start

• 100% to 25% Timer Reduction from Overload to

Short−circuit Fault

• Frequency Jittering in Normal and Frequency Foldback

Modes

• Latched OVP Input for Improved Robustness and

Latched OVP on Vcc

• Up to 30 V Vcc Maximum Rating

• +300 mA/ −500 mA Source/Sink Drive Capability

• Extremely Low No−load Standby Power

• Option for Auto−Recovery or Latched Short−Circuit

Protection

• Internal Thermal Shutdown with Hysteresis

• These are Pb−Free Devices

Typical Applications

• Converters Requiring Peak−power Capability such as

Printers Power Supplies, ac−dc Adapters for Game

Stations

ORDERING INFORMATION

See detailed ordering and shipping information in the package

dimensions section on page 2 of this data sheet.

© Semiconductor Components Industries, LLC, 2013

1

June, 2013 − Rev. 0

Publication Order Number:

NCP1249A/D

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