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NCP1203D60R2G (IC901): PWM control, high-voltage startup current. The circuit unit
has functions such as over-current protection, over-voltage protection, output
short-circuit protection and etc. The function of each pin and the inside circuit diagram
are as follows:
Pin
Pin
No.
Name
Adjust the skipping
1
Adj
2
FB
current setpoint
3
CS
Current sense input
4
GND
5
Drv
6
VCC
7
NC
Ensure a clean and
8
HV
lossless startup
ViewSonic Corporation
Function
This pin lets you adjust the level at which the cycle
skipping process takes place. Shorting this pin to ground,
peak current
permanently disables the skip cycle feature.
By connecting an optocoupler to this pin, the peak curre
Sets the peak
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 IC ground
−
Driving pulses
The driver's output to an external MOSFET.
This pin is connected to an external bulk capacitor of
Supplies the IC
typically 22
This unconnected pin ensures adequate creepage
−
distance.
Connected to the high−voltage rail, this pin injects a
constant current into the VCC capacitor during the startup
sequence
sequence.
Pin Description
F.
Confidential - Do Not Copy
18
nt
VG720-1
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