NCP1236
SIMPLIFIED INTERNAL BLOCK SCHEMATIC
Brown−out
+
−
BO
V
DD
+
−
blanking
Latch(OVP)
t
+
HV sample
HV dc
I
NTC
V
OVP
I
NTC
V
OVP
HV
CC
−
+
TSD
Latch
TSD
Dual HV
start−up
current source
blanking
+
t
Latch(OTP)
1 kW
S
R
V
OTP
Q
Latch
TSD HV current
Reset
V
clamp
Reset
UVLO
VDD
Soft−start
UVLO
end
V
CC
V
DD
management
Start
OVP
IC Start
VCC OVP
Brown−out
Reset
V
CC
V
FB(ref)
−
+
+
V
skip
20 kW
/ 5
slope
comp.
FB
HV sample
PWM
+
−
Jitter
V to I
= 0.5m x
I
OPC
(V − 125)
HV
Sawtooth
Foldback
Soft−start
+
−
Stop
+
Oscillator
DCMAX
−
+
Soft−start ramp
V
Start
Reset
FB(OPC)
IC Start
IC Stop
Clamp
t
DMAX
SSTART
End
S
Soft−start end
blanking
Q
R
DRV
GND
t
LEB
+
−
CS
+
blanking
I
LIMIT
V
ILIM
IC stop
t
BCS
UVLO
I
LIMIT
D
MAX
Brown−out
Protection
Mode
release
+
−
Latch
TSD
+
For
S
Q
R
Fault Flag
Autorecovery
protection
mode only
V
CS(stop)
timer
timer
t
t
autorec
fault
PWM
Fault
Brown−out
Reset
Figure 2. Simplified Internal Block Schematic
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