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NCP1207A_06 Datasheet, PDF (1/17 Pages) ON Semiconductor – PWM Current−Mode Controller for Free Running Quasi−Resonant Operation | |||
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NCP1207A
PWM CurrentâMode
Controller for Free Running
QuasiâResonant Operation
The NCP1207A 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 NCP1207A. 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 circuitry (OCP) makes the final
design rugged and reliable.
Features
⢠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
⢠Undervoltage Lockout for VCC Below 10 V
⢠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
⢠PbâFree Packages are Available
Typical Applications
⢠AC/DC Adapters for Notebooks, etc.
⢠Offline Battery Chargers
⢠Consumer Electronics (DVD Players, SetâTop Boxes, TVs, etc.)
⢠Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
http://onsemi.com
8
1
MARKING
DIAGRAM
8
SOICâ8
1207A
D1, D2 SUFFIX
AYWW
CASE 751
G
1
8
1
8
PDIPâ8
N SUFFIX
CASE 626
1207AP
AWL
YYWWG
1
1207A/P = Device Code
A
= Assembly Location
L, WL = Wafer Lot
Y, YY = Year
W, WW = Work Week
G
= PbâFree Package
G
= PbâFree Package
PIN CONNECTIONS
Dmg 1
FB 2
CS 3
GND 4
8 HV
7 NC
6 VCC
5 Drv
ORDERING INFORMATION
Device
Package
Shippingâ
NCP1207ADR2 SOICâ8 2500/Tape & Reel
NCP1207ADR2G
NCP1207AP
SOICâ8
(PbâFree)
PDIPâ8
2500/Tape & Reel
50 Units / Rail
NCP1207APG
PDIPâ8
(PbâFree)
50 Units / Rail
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.
© Semiconductor Components Industries, LLC, 2006
1
October, 2006 â Rev. 3
Publication Order Number:
NCP1207A/D
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