NCP1203 ON Semiconductor, NCP1203 Datasheet - Page 2

• Manufacturer Part Number: NCP1203
• Description: Current Mode Controller Fixed Frequency Operation
• Manufacturer: ON Semiconductor

PIN FUNCTION DESCRIPTION
Pin No.
UNIVERSAL
1
2
3
4
5
6
7
8
INPUT
*Please refer to the application information section
Pin Name
GND
V
Drv
Adj
CS
NC
HV
FB
CC
FILTER
EMI
Adjust the skipping peak current
Sets the peak current setpoint
Ensure a clean and lossless
Current sense input
startup sequence
Supplies the IC
The IC ground
Driving pulses
Function
-
Figure 1. Typical Application Example
+
1
2
3
4
http://onsemi.com
NCP1203
Adj
FB
CS
GND
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.
-
The driver's output to an external MOSFET.
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
the V
NCP1203
V
Drv
HV
CC
CC
2
8
7
6
5
capacitor during the startup sequence.
*
+
Aux.
Pin Description
+
V
OUT