NCP1234 ONSEMI [ON Semiconductor], NCP1234 Datasheet - Page 2

• Manufacturer Part Number: NCP1234
• Description: Fixed Frequency Current Mode Controller for Flyback Converters
• Manufacturer: ONSEMI [ON Semiconductor]

PIN FUNCTION DESCRIPTION
Pin No
(dc)
VIN
1
2
3
4
5
6
8
Pin Name
LATCH
GND
DRV
V
CS
HV
FB
CC
High−voltage pin
Figure 1. Flyback Converter Application Using the NCP1234
Latch−Off Input
LATCH
Current Sense
Drive output
GND
Feedback
Function
V
CS
FB
CC
input
NCP1234
TYPICAL APPLICATION EXAMPLE
HV
VCC
DRV
Pull the pin up or down to latch−off the controller. An internal current source
allows the direct connection of an NTC for over temperature detection
An optocoupler collector to ground controls the output regulation.
This Input senses the Primary Current for current−mode operation, and Offers
an overpower compensation adjustment.
IC Ground
Drives external MOSFET
This supply pin accepts up to 28 Vdc, with overvoltage detection
Connects to the bulk capacitor or the rectified AC line to perform the functions
of Start−up Current Source and Dynamic Self−Supply
http://onsemi.com
2
Pin Description
VOUT