NCP1282 Datasheet, PDF (1/23 Pages) ON Semiconductor – High Performance Active Clamp/Reset PWM Controller Featuring 500 V Startup

NCP1282
High Performance Active
Clamp/Reset PWM Controller
Featuring 500 V Startup
The NCP1282 is a voltage mode controller designed for ac−dc or
dc−dc converters requiring high−efficiency and low parts count. This
controller incorporates two in phase outputs with an overlap delay to
prevent simultaneous conduction and facilitates soft switching. The
main output is designed for driving a forward converter primary
MOSFET. The secondary output is designed for driving an active
clamp circuit MOSFET, a synchronous rectifier on the secondary
side, or an asymmetric half bridge circuit.
The NCP1282 reduces component count and system size by
incorporating high accuracy on critical specifications such as
maximum duty cycle limit, undervoltage detector and overcurrent
threshold. Two distinctive features of the NCP1282 are soft−stop and
a cycle skip current limit with a time threshold. Soft−stop circuitry
powers down the converter in a controlled manner if a severe fault is
detected. The cycle skip detector enables a soft−stop sequence if a
continuous overcurrent condition is present.
Additional features found in the NCP1282 include line feed−
forward, frequency synchronization up to 1.0 MHz, cycle−by−cycle
current limit with leading edge blanking (LEB), independent under
and overvoltage detectors, adjustable output overlap delay,
programmable maximum duty cycle, internal startup circuit and
soft−start.
http://onsemi.com
MARKING
DIAGRAM
SO−16
D SUFFIX
CASE 751B
NCP1282BG
AWLYWW
A
= Assembly Location
WL, L = Wafer Lot
Y
= Year
WW, W = Work Week
G
= Pb−Free Package
ORDERING INFORMATION
Device
Package
Shipping^†
NCP1282BDR2G SO−16 2500 / Tape & Reel
(Pb−Free)
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
Features
• Dual Control Outputs with Adjustable Overlap Delay
• >2.0 A Output Drive Capability
• Soft−Stop Powers Down Converter in a Controlled
Manner
• Cycle−by−Cycle Current Limit
• Cycle Skip Initiated if Continuous Current Limit
Condition Exists
• Voltage Mode Operation with Input Voltage
Feedforward
• Fixed Frequency Operation up to 1.0 MHz
• Bidirectional Frequency Synchronization
• Independent Line Undervoltage and Overvoltage
Detectors
• Minimum Operating Voltage of 8.5 V Ensures Enough
Voltage is Available for Driving High Voltage MOSFETs
• Accurate Programmable Maximum Duty Cycle Limit
• Programmable Maximum Volt−Second Product
• Programmable Soft−Start
• Internal 500 V Startup Circuit
• Precision 5.0 V Reference
• This is a Pb−Free Device*
Typical Applications
• High Power Consumer Electronics
• High Power AC−DC Converters
• High Power DC−DC Converters
• ATX Power Supplies
*For additional information on our Pb−Free strategy and soldering details, please
download the ON Semiconductor Soldering and Mounting Techniques Reference
Manual, SOLDERRM/D.
© Semiconductor Components Industries, LLC, 2006
1
December, 2006 − Rev. 0
Publication Order Number:
NCP1282/D