NCP1203
PWM Current−Mode
Controller for Universal
Off−Line Supplies Featuring
Standby and Short Circuit
Protection
Housed in SOIC−8 or PDIP−8 package, the NCP1203 represents a
major leap toward ultra−compact Switchmode Power Supplies and
represents an excellent candidate to replace the UC384X devices. Due
to its proprietary SMARTMOSt Very High Voltage Technology, the
circuit allows the implementation of complete off−line AC−DC
adapters, battery charger and a high−power SMPS with few external
components.
With an internal structure operating at a fixed 40 kHz, 60 kHz or
100 kHz switching frequency, the controller features a high−voltage
startup FET which ensures a clean and loss−less startup sequence. Its
current−mode control naturally provides good audio−susceptibility
and inherent pulse−by−pulse control.
When the current setpoint falls below a given value, e.g. the output
power demand diminishes, the IC automatically enters the so−called
skip cycle mode and provides improved efficiency at light loads
while offering excellent performance in standby conditions. Because
this occurs at a user adjustable low peak current, no acoustic noise
takes place.
The NCP1203 also includes an efficient protective circuitry which,
in presence of an output over load condition, disables the output
pulses while the device enters a safe burst mode, trying to restart.
Once the default has gone, the device auto−recovers. Finally, a
temperature shutdown with hysteresis helps building safe and robust
power supplies.
Features
http://onsemi.com
MARKING
DIAGRAM
8
8
1
SOIC−8
D1, D2 SUFFIX
CASE 751
1
x
A
L
Y
W
G
= 4, 6, or 1
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
203Dx
ALYW
G
8
PDIP−8
N SUFFIX
CASE 626
1
xx
A
WL
YY
WW
G
1
= 40, 60, or 100
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
1203Pxx
AWL
YYWWG
8
•
•
•
•
•
•
•
•
•
•
•
•
High−Voltage Startup Current Source
Auto−Recovery Internal Output Short−Circuit Protection
Extremely Low No−Load Standby Power
Current−Mode with Adjustable Skip−Cycle Capability
Internal Leading Edge Blanking
250 mA Peak Current Capability
Internally Fixed Frequency at 40 kHz, 60 kHz and 100 kHz
Direct Optocoupler Connection
Undervoltage Lockout at 7.8 V Typical
SPICE Models Available for TRANsient and AC Analysis
Pin to Pin Compatible with NCP1200
Pb−Free Packages are Available
PIN CONNECTIONS
Adj 1
FB 2
CS 3
GND 4
(Top View)
8 HV
7 NC
6 V
CC
5 Drv
Applications
•
AC−DC Adapters for Notebooks, etc.
•
Offline Battery Chargers
•
Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
©
Semiconductor Components Industries, LLC, 2005
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 13 of this data sheet.
1
October, 2005− Rev. 7
Publication Order Number:
NCP1203/D