NCP1377_06 Datasheet, PDF (1/16 Pages) ON Semiconductor – PWM Current−Mode Controller for Free−Running Quasi−Resonant Operation

NCP1377, NCP1377B
PWM Current−Mode
Controller for Free−Running
Quasi−Resonant Operation
The NCP1377 combines a true current mode modulator and a
demagnetization detector which ensures full borderline/critical
Conduction Mode in any load/line conditions together with
minimum drain voltage switching (Quasi−Resonant 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. For
NCP1377, an internal 8.0 ms timer prevents the free−run frequency to
exceed 100 kHz (therefore below the 150 kHz CISPR−22 EMI
starting limit), while the skip adjustment capability lets the user
select the frequency at which the burst foldback takes place. For
NC1377B, the internal timer duration is reduced to 3.0 ms to allow
operation at higher frequencies (up to 300 kHz).
The transformer core reset detection is done through an auxiliary
winding which, brought via a dedicated pin, also enables fast
Over Voltage Protection (OVP). Once an OVP has been detected, the
IC permanently latches off. The 1377 features a sampling time of
4.5 ms whereas it is 1.5 ms for the B version.
The NCP1377 also features an efficient protective circuitries
which, in presence of an overcurrent condition, disables the output
pulses and enters a safe burst mode, trying to restart. Once the default
has gone, the device auto−recovers. Finally an internal 1.0 ms
Soft−Start eliminates the traditional startup stress.
Features
• Free−Running Borderline/Critical Mode Quasi−Resonant Operation
• Latched Overvoltage Protection
• Auto−Recovery Short−Circuit Protection Via UVLO Crossover
• External Latch Triggering, e.g. Via Overtemperature Signal
• Current−Mode with Adjustable Skip Cycle Capability
• Internal 1.0 ms Soft−Start
• Internal Temperature Shutdown
• Internal Leading Edge Blanking
• 500 mA Peak Current Source/Sink Capability
• Under Voltage Lockout Level of 12.5 V (On) and 7.5 V (Min)
• Direct Optocoupler Connection
• SPICE Models Available for TRANsient Analysis
• Internal Minimum T_OFF
• Pb−Free Packages are Available
Typical Applications
• AC−DC Adapters for Notebooks, etc.
• Offline Battery Chargers
• Consumer Electronics (DVD Players, Set−Top Boxes, TVs, etc.)
• Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
http://onsemi.com
8
1
SOIC−8
DR SUFFIX
CASE 751
MARKING DIAGRAMS
8
1377
ALYW
G
1
8
1377B
ALYW
G
1
8
1
SOIC−7
D1 SUFFIX
CASE 751U
8
377D1
ALYW G
G
1
8
1
PDIP−7 ¹
P SUFFIX
CASE 626B
1377P
AWL
YYWWG
1
1377BP
AWL
YYWWG
A
= Assembly Location
L, WL = Wafer Lot
Y, YY = Year
W, WW = Work Week
G or G = Pb−Free Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
Dmg 1
FB 2
CS 3
GND 4
8 HV
6 V_CC
5 Drv
(Top View)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 14 of this data sheet.
© Semiconductor Components Industries, LLC, 2006
1
October, 2006 − Rev. 7
Publication Order Number:
NCP1377/D