NCP1244 Datasheet, PDF (1/40 Pages) ON Semiconductor – Fixed Frequency Current Mode Controller

NCP1244
Fixed Frequency Current
Mode Controller for Flyback
Converters
The NCP1244 is a new fixed−frequency current−mode controller
featuring the Dynamic Self−Supply. This function greatly simplifies
the design of the auxiliary supply and the V_CC capacitor by activating
the internal startup current source to supply the controller during
start−up, transients, latch, stand−by etc. This device contains a special
HV detector which detect the application unplug from the AC input
line and triggers the X2 discharge current.
It features a timer−based fault detection that ensures the detection of
overload and an adjustable compensation to help keep the maximum
power independent of the input voltage.
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 the robust power supply designs.
A dedicated Off mode allows to reach the extremely low no load
input power consumption via “sleeping” whole device and thus
minimize the power consumption of the control circuitry.
http://onsemi.com
MARKING
DIAGRAM
SOIC−7
CASE 751U
8
44Xfff
ALYWX
G
1
44Xfff = Specific Device Code
X = A or B
fff = 065 or 100
A = Assembly Location
L = Wafer Lot
Y = Year
W = Work Week
G
= Pb−Free Package
Features
PIN CONNECTIONS
• Fixed−Frequency Current−Mode Operation (65 kHz and 100 kHz
Latch 1
8 HV
frequency options)
• Frequency Foldback then Skip Mode for Maximized Performance in
Light Load and Standby Conditions
• Timer−Based Overload Protection with Latched (Option A) or
FB 2
CS 3
GND 4
6 V_CC
5 DRV
Auto−Recovery (Option B) Operation
(Top View)
• High−voltage Current Source with Dynamic Self−Supply,
Simplifying the Design of the V_CC Circuitry
• Frequency Modulation for Softened EMI Signature
• Adjustable Overpower Protection Dependant on the Bulk Voltage
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 39 of this data sheet.
• Latch−off Input Combined with the Overpower Protection Sensing
Input
• V_CC Operation up to 28 V, With Overvoltage Detection
• 500/800 mA Source/Sink Drive Peak Current
Capability
• 10 ms Soft−Start
Typical Applications
• AC−DC Adapters for Notebooks, LCD, and Printers
• Offline Battery Chargers
• Internal Thermal Shutdown
• No−Load Standby Power < 30 mW
• X2 Capacitor in EMI Filter Discharging Feature
• Consumer Electronic Power Supplies
• Auxiliary/Housekeeping Power Supplies
• Offline Adapters for Notebooks
• These Devices are Pb−Free and Halogen Free/BFR Free
© Semiconductor Components Industries, LLC, 2014
1
July, 2014 − Rev. 1
Publication Order Number:
NCP1244/D