NCP1382 ON Semiconductor, NCP1382 Datasheet - Page 24

• Manufacturer Part Number: NCP1382
• Description: Quasi Resonant Current Mode Controller Featuring Pfc Go To Standby Function
• Manufacturer: ON Semiconductor

PFC Behavior During BO Conditions
PFC controller consumption would prevent the charging of
the V
comes back and a clean startup sequence has properly ended.
Soft-start
power on sequence (P
lower the acoustical noise in the transformer. As soon as
V
from nearly zero up to the maximum clamping level (e.g.
0.8 V / R
soft-start activation.
condition to implement our soft-burst. This Soft-Skip is
cancelled whenever a fault condition appears, in order not to
degrade the transient behavior in case of load transients
when the controller is initially in skip mode.
A mix of conditions, BO, short-circuit and UVLO fault are represented on this diagram. In BO, the pulses (pulse ok signal) are started at
V
short-circuit), there is a latch-off phase but the timer is flat since there is no short-circuit.
CC
CC
During brown-out, the PFC is disabled; otherwise the
The NCP1381/82 features a soft-start activated during the
A shorter soft-start is also activated during the skip cycle
= 15 V and there is no latch-off phase. In short-circuit, pulses are stopped by the timer and finally, in a UVLO conditions (not a
reaches 15 V, the peak current is gradually increased
CC
capacitor. The PFC will be shutdown until BO
sense
). Every restart attempt is followed by a
ON
) and in short-circuit conditions to
BO Interruption
50.0m
V
CC
150m
Short-Circuit
NCP1381, NCP1382
Interruption
http://onsemi.com
Figure 37.
250m
24
0 V (Fresh P
or V
Figure 38. Soft-Start is Activated During a Startup
VCC
Current
Comp.
Pulse
Sense
V
B
CClatch
OK
CC
OK
VCC
VCC
latch
350m
OFF
ON
ON
Sequence or an OCP Condition
UVLO Interruption
)
Timer
V
in
450m
15 V
5 ms
Max I
P