NCP1203
*
V
OUT
+
Aux.
+
NCP1203
Adj HV
FB
1
2
3
4
8
7
6
5
CS V
CC
EMI
FILTER
GNDDrv
UNIVERSAL
INPUT
+
*Please refer to the application information section
Figure 1. Typical Application Example
PIN FUNCTION DESCRIPTION
Pin No. Pin Name
Function
Pin Description
1
2
3
Adj
FB
CS
Adjust the skipping peak current
Sets the peak current setpoint
Current sense input
This pin lets you adjust the level at which the cycle skipping process takes
place. Shorting this pin to ground, permanently disables the skip cycle
feature.
By connecting an optocoupler to this pin, the peak current setpoint is
adjusted accordingly to the output power demand. Skip cycle occurs when
FB falls below Vpin1.
This pin senses the primary current and routes it to the internal comparator
via an L.E.B.
4
5
6
7
8
GND
Drv
The IC ground
Driving pulses
Supplies the IC
−
−
The driver’s output to an external MOSFET.
V
CC
This pin is connected to an external bulk capacitor of typically 22 mF.
This unconnected pin ensures adequate creepage distance.
Connected to the high−voltage rail, this pin injects a constant current into
NC
HV
Ensure a clean and lossless
startup sequence
the V capacitor during the startup sequence.
CC
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2
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