NCP1028 ON Semiconductor, NCP1028 Datasheet - Page 14

• Manufacturer Part Number: NCP1028
• Description: High?voltage Switcher For Medium Power Offline Smps
• Manufacturer: ON Semiconductor

testifying for a badly coupled power secondary and
primary auxiliary windings. Some situations exist where an
output short-circuit make the auxiliary winding collapse
In Figure 26, one can see that the V
Figure 27. The auxiliary winding collapses in presence of a short-circuit. Pulses are immediately stopped
as V
CC
CC
crosses the minimum operating voltage, VCC
is still alive,
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NCP1028
14
before the timer completion. In this particular case, the
Undervoltage Lock Out (UVLO) circuitry has the priority
and safely cuts off all driving pulses. Figure 27 describes
this variation.
(min)
.