NCP1249 Datasheet, PDF (1/31 Pages) ON Semiconductor – High-Voltage Current-Mode PWM Controller Featuring Peak Power Excursion and Extremely Low Stand-by Power Consumption

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 V_cc
• Up to 30 V V_cc 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