NCP1378 ON Semiconductor, NCP1378 Datasheet - Page 2

• Manufacturer Part Number: NCP1378
• Description: PWM Current-Mode Controller
• Manufacturer: ON Semiconductor

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PIN FUNCTION DESCRIPTION
Pin
1
2
3
4
5
6
7
8
Symbol
Demag
GND
V
Drv
CS
NC
HV
FB
CC
*Please refer to the application information section.
Core reset detection and OVP
Sets the peak current setpoint
Current sense input and skip
+
cycle level selection
High−voltage pin
Supplies the IC
The IC ground
Driving pulses
Function
OVP and
Demag
−
Figure 1. Typical Application Schematic
1
2
3
4
NCP1378
http://onsemi.com
The auxiliary FLYBACK signal ensures discontinuous operation and offers a
fixed overvoltage detection level of 5.2 V.
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.
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.
−
The driver’s output to an external MOSFET.
This pin is connected to an external bulk capacitor of typically 47 mF.
This unconnected pin ensures adequate creepage distance.
Connected to the high−voltage rail, this pin injects a constant current into the
V
NCP1378
CC
8
7
6
5
bulk capacitor and ensures a clean lossless startup sequence.
2
R*
+
Description
Y1 Type
+
12 V @ 1 A
GND