NCP1246-D Datasheet, PDF (1/39 Pages) ON Semiconductor – Fixed Frequency Current Mode Controller for Flyback Converters

NCP1246
Fixed Frequency Current
Mode Controller for Flyback
Converters
The NCP1246 is a new fixed−frequency current−mode controller
http://onsemi.com
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. This HV structure allows
the brown−out detection as well.
It features a timer−based fault detection that ensures the detection of
SOIC−7
CASE 751U
MARKING
DIAGRAM
8
46Xff
ALYWX
G
1
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
46Xff = Specific Device Code
X = A or B
ff = 65 or 100
A = Assembly Location
L = Wafer Lot
Y = Year
W = Work Week
G
= Pb−Free Package
input power consumption via “sleeping” whole device and thus
minimize the power consumption of the control circuitry.
Features
• Fixed−Frequency Current−Mode Operation (65 kHz and 100 kHz
frequency options)
PIN CONNECTIONS
Latch 1
FB 2
CS 3
8 HV
6 V_CC
• Frequency Foldback then Skip Mode for Maximized Performance in
GND 4
5 DRV
Light Load and Standby Conditions
• Timer−Based Overload Protection with Latched (Option A) or
(Top View)
Auto−Recovery (Option B) 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
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 38 of this data sheet.
• Adjustable Overpower Protection Dependant on the Bulk Voltage
• 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
• Internal Thermal Shutdown
• No−Load Standby Power < 30 mW
• X2 Capacitor in EMI Filter Discharging Feature
• These Devices are Pb−Free and Halogen Free/BFR Free
Typical Applications
• AC−DC Adapters for Notebooks, LCD, and Printers
• Offline Battery Chargers
• Consumer Electronic Power Supplies
• Auxiliary/Housekeeping Power Supplies
• Offline Adapters for Notebooks
This document contains information on a product under development. ON Semiconductor
reserves the right to change or discontinue this product without notice.
© Semiconductor Components Industries, LLC, 2012
1
October, 2012 − Rev. 1
Publication Order Number:
NCP1246/D