Datasheet
NCL30000
http://onsemi.com
3
Table 1. PIN FUNCTION DESCRIPTION
Pin Name Function
1 MFP The multi-function pin is connected to the internal error amplifier. By pulling this pin below the V
uvp
threshold, the
controller is disabled. In addition, this pin also has an over voltage comparator which will disable the controller in the
event of a fault.
2 COMP The COMP pin is the output of the internal error amplifier. A compensation network is connected between this pin
and ground to set the loop bandwidth. Normally this bandwidth is set at a low frequency (typically 10 Hz − 20 Hz) to
achieve high power factor and low total harmonic distortion (THD).
3 C
t
The C
t
pin sources a regulated current to charge an external timing capacitor. The PWM circuit controls the power
switch on time by comparing the C
t
voltage to an internal voltage derived from V
Control
. The C
T
pin discharges the
external timing capacitor at the end of the on time cycle.
4 CS The CS input is used to sense the instantaneous switch current in the external MOSFET. This signal is filtered by an
internal leading edge blanking circuit.
5 ZCD The voltage of an auxiliary zero current detection winding is sensed at this pin. When the ZCD control block circuit
detects that the winding has been demagnetized, a control signal is sent to the gate drive block to turn on the
external MOSFET.
6 GND This is the analog ground for the device. All bypassing components should be connected to the GND pin with a short
trace length.
7 DRV The high current capability of the totem pole gate drive (+0.5/−0.8 A) makes it suitable to effectively drive high gate
charge power MOSFETs. The driver stage provides both passive and active pull down circuits that force the output to
a voltage less than the turn-on threshold voltage of the power MOSFET when V
CC(on)
is not reached.
8 V
CC
This pin is the positive supply of the controller. The circuit starts to operate when V
CC
exceeds V
CC(on)
, nominally
12 V and turns off when V
CC
goes below V
CC(off)
, typically 9.5 V. After startup, the operating range is 10.2 V up to
20 V.
Q1
EMI
FILTER
1
2
3
4
8
7
6
5
C
in
R
CS
D
1
C
1
C
comp
C
tim
R
y
R
LED
R
ZCD
R
L
R
2
R
1
R
SU
MFP
COMP
VCC
DRV
GND
ZCD
C
T
CS
AC
Line
Input
D
out
C
OUT
R
c
R
t
R
a
R
b
R
x
GND
4
3
2
1
7
8
5
6
IN1+
NCS1002
IN1−
IN2−
IN2+
OUT1
OUT2
VCC
NCL30000
+
−
+
−
C
c
C
v
Figure 2. Simplified Flyback Application with Secondary side Constant Current Control