Datasheet

NCP1028
http://onsemi.com
2
85-265 VAC
+
BO
+ +
1
2
3
4
5
7
8
NCP1028
OPP*
+
V
out
GND
Figure 1. Typical Application
Ramp
Comp.*
*Optional component
PIN FUNCTION DESCRIPTION
Pin No. Symbol Function Description
1 V
CC
Powers the Internal
Circuitry
This pin is connected to an external capacitor of typically 22 mF.
2 Ramp Comp. Ramp Compensation
in CCM
To extend the duty cycle operation in Continuous Conduction Mode (CCM),
pin 3 offers the ability to inject ramp compensation in the controller. If unused,
short this pin to V
CC
.
3 Brown-Out Brown-Out and
Latchoff Input
By monitoring the bulk level via a resistive network, the circuit protects itself
from low mains conditions. If an external event brings this pin above 4.0 V,
the part fully latches off.
4 FB Feedback Signal Input By connecting an optocoupler to this pin, the peak current setpoint is adjusted
accordingly to the output power demand.
5 Drain Drain Connection The internal drain power switch circuit connection.
- - - This unconnected pin ensures adequate creepage distance.
7 OPP Over Power Protection Driving this pin reduces the power supply capability in high line conditions. If
no Over Power Protection is needed, short this pin to ground.
8 GND The IC Ground -