NCP1603
http://onsemi.com
3
I
S
UVLO
Current
Mirror
FB1
CS1
Regulation Block
Current
Mirror
Out1
GND1
Ramp
PFC
Osc
Thermal
Shutdown
PWM
LEB
125 ms
2.5 ms
Softstart
CS2
FB2
Oscillator
100 kHz
125 ms
delay
HV
S Q
R
3V
OVP
Out2
Gnd2
PWM
Standby
OR
5V
1V max
18k
55k
20k
25k
Fault2
0.75V
0.75V/ 1.25V
Fault2
OR
300k
OR
5ms Jittering
Zero Current
Protection
Overcurrent
Protection
Overvoltage
Shutdown / UVP
delay
Max duty
R Q
S
= 80%
200ns
(9 / 10.5V)
Voltage
Regulator
Internal bias
FB1
ref
ref
reg
V
I I
96%I
(12.6 / 7.7V)
(5.6 / 4V)
1 0
0~2.3V ramp
100 kHz
5ms Jittering
R
S Q
&
&
S R
Q
1 0
S
R Q
&
start_Vaux
start_Vaux
3.9V max
clamp
&
+
+
+
+
+
+
11
9
5
16
8
2
3
4
1
6
7
12
10
14
13
10V
10V
9V
9V
18V
20V
9V
9V
Thermal
Shutdown
+
5/ 3.5 V
R
Q
S
0 1
delay
9 V
Detection
&
3.2mA
0 1
+
clock
disable
initially
Error
Fault1
Vaux
Internal bias
PFC
Modulation
&
V
CC1
94mA
45mA
(I
FB1
< 8% I
REF
)
I
FB1
(I
FB1
> 107% I
REF
)
V
CS2
V
FB2
V
SS
(140/165癈)
latchoff, reset
when V
CC2
< 4V
disable V
aux
when V
CC2
< 7.7V
V
CC2
mgmt
V
CC2
V
aux
V
control
I
ch
C
3
C
1
R
1
R
2
R
3
V
ton
V
CC1
(I
S
> 203 mA)
(95/140癈)
(I
S
< 14 mA)
V
CC2
Figure 2. Functional Block Diagram
latchoff, reset
when V
CC2
< 4V
Fault1