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NCP1207 Datasheet, PDF (1/18 Pages) ON Semiconductor – PWM Current-Mode Controller | |||
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NCP1207
PWM CurrentâMode
Controller for Free Running
QuasiâResonant Operation
The NCP1207 combines a true current mode modulator and a
demagnetization detector to ensure full borderline/critical
Conduction Mode in any load/line conditions and minimum drain
voltage switching (QuasiâResonant operation). Due to its inherent skip
cycle capability, the controller enters burst mode as soon as the power
demand falls below a predetermined level. As this happens at low peak
current, no audible noise can be heard. An internal 8.0 ms timer prevents
the freeârun frequency to exceed 100 kHz (therefore below the 150 kHz
CISPRâ22 EMI starting limit), while the skip adjustment capability lets
the user select the frequency at which the burst foldback takes place.
The Dynamic SelfâSupply (DSS) drastically simplifies the
transformer design in avoiding the use of an auxiliary winding to supply
the NCP1207. This feature is particularly useful in applications where
the output voltage varies during operation (e.g. battery chargers). Due to
its highâvoltage technology, the IC is directly connected to the
highâvoltage DC rail. As a result, the shortâcircuit trip point is not
dependent upon any VCC auxiliary level.
The transformer core reset detection is done through an auxiliary
winding which, brought via a dedicated pin, also enables fast
Overvoltage Protection (OVP). Once an OVP has been detected, the IC
permanently latches off.
Finally, the continuous feedback signal monitoring implemented with
an Overcurrent Fault Protection (OCP) circuitry makes the final design
rugged and reliable.
Features
⢠PbâFree Packages are Available*
⢠FreeâRunning Borderline/Critical Mode QuasiâResonant Operation
⢠CurrentâMode with Adjustable SkipâCycle Capability
⢠No Auxiliary Winding VCC Operation
⢠AutoâRecovery Overcurrent Protection
⢠Latching Overvoltage Protection
⢠External Latch Triggering, e.g. Via Overtemperature Signal
⢠500 mA Peak Current Source/Sink Capability
⢠Internal 1.0 ms SoftâStart
⢠Internal 8.0 ms Minimum TOFF
⢠Adjustable Skip Level
⢠Internal Temperature Shutdown
⢠Direct Optocoupler Connection
⢠SPICE Models Available for TRANsient Analysis
Typical Applications
⢠ACâDC Adapters for Notebooks, etc.
⢠Offline Battery Chargers
⢠Consumer Electronics (DVD Players, SetâTop Boxes, TVs, etc.)
⢠Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
*For additional information on our PbâFree strategy and soldering details, please
download the ON Semiconductor Soldering and Mounting Techniques
Reference Manual, SOLDERRM/D.
© Semiconductor Components Industries, LLC, 2004
1
October, 2004 â Rev. 8
http://onsemi.com
8
1
8
1
SOICâ8
D1, D2 SUFFIX
CASE 751
MARKING
DIAGRAMS
8
1207
ALYW
1
8
PDIPâ8
N SUFFIX
CASE 626
1
1207P
AWL
YYWW
1207/P = Device Code
A
= Assembly Location
WL, L = Wafer Lot
YY, Y = Year
WW, W = Work Week
PIN CONNECTIONS
DMG 1
FB 2
CS 3
GND 4
8 HV
7 NC
6 VCC
5 Drv
(Top View)
ORDERING INFORMATION
Device
Package
Shippingâ
NCP1207DR2
SOICâ8 2500/Tape & Reel
NCP1207DR2G SOICâ8 2500/Tape & Reel
(PbâFree)
NCP1207P
PDIPâ8
50 Units/Tube
NCP1207PG
PDIPâ8
(PbâFree)
50 Units/Tube
â 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.
Publication Order Number:
NCP1207/D
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