ncp1239f ON Semiconductor, ncp1239f Datasheet - Page 7

• Manufacturer Part Number: ncp1239f
• Description: Lowstandby High Performance Pwm Controller
• Manufacturer: ON Semiconductor

SS / timer
PFC_Vcc
Fault
detect
REF5V
Skip
adjust
BO
FB
Rt
7
3
1
6
2
5
4
8
1mA
2.5V
10k
to Skip
0.5V / 0.25V
Vdd
100k
BO_in
+
Vcc
Vdd
5V
20k
Vdd
pfcON
2.5V
+
450mV
FB>1.6*Vpin1 =>Stby_detect RESET
25r
−
+
+
FB<Vpin1 => Skip high
FB
Ramp
Compensation
Vdd
Figure 3. NCP1239F Internal Circuit Architecture
pfcOFF
15r
/ 3
+
−
+
−
Oscillator
−
−
+
+
“Jittered”
Reference
Stby
Soft−Start
and timer
management
Soft−Start
Ipk limit
Soft−Start
Ipk limit
Vcc < 4V
3.2V
BO_out
S
R
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Jittering
Modulation
Q
Q
Skip
Startup Phase
CLK
S
R
NCP1239
Q
Q
Fault
Jittering
Modulation
OVL
Vstop
Stby_detect
Stby_detect
Error_Flag
7
0.9V
TSD
Internal
Thermal
Shutdown
Error flag
32k
−
stdwn
CLK
regOUT
S
R
Q
Q
+
Skip
pfcON
S
R
OUTon
Divider by 2
Q
Q
−
Vdd
+
OVL
Vstop
0.5V
+
UVLOs
Latch
Reset
UVLO
(Vcc<VccOFF)
LEB
Output
Buffer
LEB
Regul
Vcc<7V
Vdd
clamp
75 mA/V x V
14V
BO_in
pin5
16
15
14
13
12
10
11
9
Vcc
HV
CS
Over Power
Limit
Drv
GND