NCL37733
INTERNAL CIRCUIT ARCHITECTURE
Enable
STOP
V
V
REF
DD
Aux_SCP
OFF
ZCD
Over Voltage
Protection
VCC
UVLO
Latch
Fault
Management
VCC Management
Internal
Thermal
Shutdown
VCC_max
VCC Over Voltage
Protection
WOD_SCP
BO_NOK
FF_mode
DRV
VCC
Zero Crossing Detection Logic
(ZCD Blanking, Time−Out, ...)
Clamp
Circuit
Aux. Winding Short Circuit Prot.
DRV
Aux_SCP
S
Q
Q
CS_ok
V
VS
DRV
R
Line
feed−forward
V
VS
V
REF
STOP
V
TF
CS/ZCD
Power Factor and
Constant−Current
Control
Leading
Edge
Blanking
CS_reset
Ipkmax
Maximum
on time
STOP
t
on,max
COMP
Ipkmax
Max. Peak
Current
Limit
V
VS
CS_ok
CS Short
Protection
BO_NOK
VS
Brown−Out
UVLO
t
on,max
Winding and
Output Diode
Short Circuit
Protection
WOD_SCP
GND
Figure 3. Internal Circuit Architecture
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