NCP1248 Datasheet, PDF (1/36 Pages) ON Semiconductor – Fixed Frequency Current Mode Controller

NCP1248
Fixed Frequency Current
Mode Controller for Flyback
Converters
The NCP1248 is a new fixed-frequency current-mode controller
featuring the Dynamic Self-Supply. This function greatly simplifies
http://onsemi.com
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
SOIC−7
line and triggers the X2 discharge current. This HV structure allows
CASE 751U
the brown-out detection as well.
It features a timer-based fault detection that ensures the detection of
MARKING DIAGRAM
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
8
48Axxx
ALYWX
G
1
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.
Features
• Fixed-Frequency Current-Mode Operation using 65 kHz/100 kHz
48Axxx = Specific Device Code
xxx = 065 for 65 kHz
= 100 for 100 kHz
A
= Assembly Location
L
= Wafer Lot
Y
= Year
W
= Work Week
G
= Pb-Free Package
Switching Frequency
• Frequency Foldback then Skip Mode for Maximized Performance
PIN CONNECTIONS
in Light Load and Standby Conditions
• Timer-Based Overload Protection with Latched (Option A)
Operation
• High-voltage Current Source with Brown-Out Detection and
Dynamic Self-Supply, Simplifying the Design of the V_CC
Circuitry
• Frequency Modulation for Softened EMI Signature
1
Latch
2
FB
3
CS
4
GND
8
HV
6
V_CC
5
DRV
(Top View)
• Adjustable Overpower Protection Dependant on the Bulk Voltage
• Latch-off Input Combined with the Overpower Protection
Sensing Input
ORDERING INFORMATION
See detailed ordering and shipping information on page 35 of
this data sheet.
• V_CC Operation up to 28 V, With Overvoltage Detection
• 500/800 mA Source/Sink Drive Peak Current Capability
Typical Applications
• 10 ms Soft-Start
• AC-DC Adapters for Notebooks, LCD, and Printers
• Internal Thermal Shutdown
• Offline Battery Chargers
• No-Load Standby Power < 30 mW
• Consumer Electronic Power Supplies
• X2 Capacitor in EMI Filter Discharging Feature
• Auxiliary/Housekeeping Power Supplies
• These Devices are Pb-Free and Halogen Free/BFR Free
• Offline Adapters for Notebooks
© Semiconductor Components Industries, LLC, 2014
1
December, 2014 − Rev. 0
Publication Order Number:
NCP1248/D