VIPER15

Manufacturer Part NumberVIPER15
DescriptionVIPerPlus family: quasi-resonant high performance off line high voltage converter
ManufacturerSTMicroelectronics
VIPER15 datasheet
 


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VIPER15
7.4
Power-down description
At converter power-down, the system loses regulation as soon as the input voltage is so low
that the peak current limitation is reached. The V
the V
threshold the power MOSFET is switched OFF, the energy transfers to the IC is
DDoff
interrupted and consequently the V
if the V
is lower than the threshold V
IN
the power-down completed. This feature is useful to prevent converter’s restart attempts and
ensures monotonic output voltage decay during the system power-down.
7.5
Auto-restart description
If after a converter power-down, the V
sequence is not inhibited and will be activated only when the V
V
threshold (reported on
DD(RESTART)
current generator restarts the V
below V
DD(RESTART)
of a fault condition. After a fault condition, the charging current, I
instead of 3 mA of the normal power-up converter phase. This feature together with the low
V
threshold (reported on
DD(RESTART)
restart attempts of the IC has a very long repetition rate and the converter works safely with
extremely low power throughput. The
event.
Figure 26. Timing diagram: behavior after short-circuit
Short circuit occurs here
V
DD
V
DDon
V
DDoff
V
DD(RESTART)
V
FB
V
FBolp
V
FBlin
V
DS
I
DD
I
(0.6mA)
DDch
DD
voltages decreases, see
DD
DRAIN_START
is higher than V
IN
Table 7 on page 7
capacitor charging only when the V
DD
. The scenario above described is for instance a power-down because
Table 7 on page 7
Figure 26
shows the IC behavioral after a short-circuit
0.3 x T
REPETITION
Doc ID 15455 Rev 5
Operation description
voltage drops and when it falls below
Figure 23 on page 17
, the start-up sequence is inhibited and
the power-up
DRAIN_START,
voltage drops down the
DD
). This means that the HV start-up
voltage drops
DD
, is reduced to 0.6 mA
DDch
) ensures that, after a fault, the
T
REPETITION
. Later,
time
time
time
time
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