NCP1250ASN100T1G ONSEMI [ON Semiconductor], NCP1250ASN100T1G Datasheet - Page 3

• Manufacturer Part Number: NCP1250ASN100T1G
• Description: Current-Mode PWM Controller for Off-line Power Supplies
• Manufacturer: ONSEMI [ON Semiconductor]

OPP
FB
CS
RFB
Vlatch
vdd
vdd
Vskip
/ 4.2
Vfold
OVP
gone?
Frequency
modulation
LEB
Frequency
foldback
Figure 2. Internal Circuit Architecture
Up counter
RST
R
4
S
600−ns time
constant
250 mV
peak current
freeze
Q
Q
Power on
reset
Rramp
http://onsemi.com
VOPP
vdd
The soft−start is activated during:
− the startup sequence
− the auto−recovery burst mode
3
1−us
blanking
65
100 kHz
clock
power
on reset
+
VFB < 1.05 V ? setpoint = 250 mV
Vcc and logic
management
Vlimit
Vlimit + VOPP
hiccup
IpFlag
R
S
Q
Q
4 ms
SS
UVLO
IpFlag
Rlim
Iscr
Clamp
GND
Vcc
Drv