NCP1236
Fixed Frequency Current
Mode Controller for Flyback
Converters
The NCP1236 is a new fixed−frequency current−mode controller
featuring Dynamic Self−Supply (DSS). This device is pin−to−pin
compatible with the previous NCP12xx families.
http://onsemi.com
MARKING
The DSS function greatly simplifies the design of the auxiliary
supply and the V capacitor by activating the internal startup current
CC
DIAGRAM
source to supply the controller during transients.
8
Due to frequency foldback, the controller exhibits excellent
efficiency in light load condition while still achieving very low
standby power consumption. Internal frequency jittering, ramp
compensation, and a versatile latch input make this controller an
excellent candidate for converters where components cost is the key
constraints.
36Xff
ALYWX
G
SOIC−7
CASE 751U
1
36Xff = Specific Device Code
X = A, B, C or D
In addition, the controller includes a new high voltage circuitry that
combines a start−up current source and a brown−out detector able to
sense the input voltage either from the rectified ac line or the dc
filtered bulk voltage. The high voltage sensing circuitry is used for the
overpower protection purposes as well. Overpower protection,
overload protection, and next protective features increases safety level
of the final application.
Finally, due to a careful design, the precision of critical parameters
is well controlled over the entire temperature range (−40C to
+125C).
ff = 65 or 100
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
A
L
Y
W
G
PIN CONNECTIONS
Latch
FB
1
2
3
4
8
HV
Features
V
CC
6
5
CS
Fixed−Frequency Current−Mode Operation with Built−In Ramp
Compensation
65 kHz or 100 kHz Oscillator Frequency
GND
DRV
(Top View)
Frequency Foldback then Skip Mode for Maximized Performance in
Light Load and Standby Conditions
Timer−Based Overload Protection with Latched (option A) or
Auto−Recovery (option B) Operation, Shortened Overload Timer for
Increased Safety (options C and D), (see all options on page 2)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 33 of this data sheet.
High−voltage Current Source with Brown−Out
detection and Dynamic Self−Supply, Simplifying the
Internal Thermal Shutdown
Pin−to−Pin Compatible with the Existing NCP12xx
Series
Design of the V Capacitor
CC
Frequency Modulation for Softened EMI Signature,
including during Frequency Foldback mode
Adjustable Overpower Compensation
Latch−off Input for Severe Fault Conditions, Allowing
Direct Connection of an NTC for Overtemperature
Protection (OTP)
These Devices are Pb−Free, Halogen Free/BFR Free
and are RoHS Compliant
Typical Applications
AC−DC Adapters for Notebooks, LCD, and Printers
Offline Battery Chargers
Consumer Electronic Power Supplies
Auxiliary/Housekeeping Power Supplies
V Operation up to 28 V, with Overvoltage Detection
$500 mA Peak Source / Sink Current Drive Capability
4.0 ms Soft−Start
CC
Semiconductor Components Industries, LLC, 2013
1
Publication Order Number:
April, 2013 − Rev. 3
NCP1236/D