NCP1011 ONSEMI [ON Semiconductor], NCP1011 Datasheet - Page 15

• Manufacturer Part Number: NCP1011
• Description: Self-Supplied Monolithic Switcher for Low Standby- Power Offline SMPS
• Manufacturer: ONSEMI [ON Semiconductor]

Soft−Start
activated during the power on sequence (PON). As soon as
V
increased from nearly zero up to the maximum internal
clamping level (e.g. 350 mA). This situation lasts 1.0 ms
and further to that time period, the peak current limit is
blocked to the maximum until the supply enters regulation.
The soft−start is also activated during the over current burst
Non−Latching Shutdown
temporarily and authorize its restart once the default has
disappeared. This option can easily be accomplished
through a single NPN bipolar transistor wired between FB
CC
The NCP101X features an internal 1.0 ms soft−start
In some cases, it might be desirable to shut off the part
reaches VCC
Figure 23. A non−latching shutdown where pulses are stopped as long as the NPN is biased.
Figure 22. Soft−Start is activated during a startup sequence or an OCP condition.
ON/OFF
OFF
0 V (Fresh PON)
4.7 V (Overload)
V
Current
CC
, the peak current is gradually
Sense
NCP1010, NCP1011, NCP1012, NCP1013, NCP1014
or
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15
8.5 V
(OCP) sequence. Every restart attempt is followed by a
soft−start activation. Generally speaking, the soft−start will
be activated when V
power−on sequence) or 4.7 V, the latch−off voltage
occurring during OCP. Figure 22 portrays the soft−start
behavior. The time scales are purposely shifted to offer a
better zoom portion.
1.0 ms
and ground. By pulling FB below the internal skip level
(Vskip), the output pulses are disabled. As soon as FB is
relaxed, the IC resumes its operation. Figure 23 depicts the
application example.
Max Ip
+
CV
cc
1
2
3
4
CC
ramps up either from zero (fresh
8
7
5
Drain