NCP1378

http://onsemi.com

2

Figure 1. Typical Application Schematic

1

8

2

3

4

6

5

7

NCP1378

OVP and

Demag

+

Universal

Network

R*

+

12 V @ 1 A

GND

+

Y1 Type

*Please refer to the application information section.

PIN FUNCTION DESCRIPTION

Pin

Symbol

Function

Description

1

Demag

Core reset detection and OVP

The auxiliary FLYBACK signal ensures discontinuous operation and offers a

fixed overvoltage detection level of 5.2 V.

2

FB

Sets the peak current setpoint

By connecting an optocoupler to this pin, the peak current setpoint is

adjusted accordingly to the output power demand. By bringing this pin below

the internal skip level, you shut off the device.

3

CS

Current sense input and skip

cycle level selection

This pin senses the primary current and routes it to the internal comparator

via an L.E.B. By inserting a resistor in series with the pin, you control the

level at which the skip operation takes place.

4

GND

The IC ground

−

5

Drv

Driving pulses

The driver’s output to an external MOSFET.

6

Supplies the IC

This pin is connected to an external bulk capacitor of typically 47 mF.

7

NC

−

This unconnected pin ensures adequate creepage distance.

8

HV

High−voltage pin

Connected to the high−voltage rail, this pin injects a constant current into the