VIPER26

Manufacturer Part NumberVIPER26
DescriptionVIPerPlus family: fixed frequency high performance off line high voltage converter
ManufacturerSTMicroelectronics
VIPER26 datasheet
 
1
2
3
4
5
6
7
8
9
10
11
Page 11
12
Page 12
13
Page 13
14
Page 14
15
Page 15
16
Page 16
17
Page 17
18
Page 18
19
Page 19
20
Page 20
21
22
23
24
25
Page 17/25

Download datasheet (810Kb)Embed
PrevNext
VIPER26
14
Automatic auto restart after overload or short-circuit
The overload protection is implemented in automatic way using the integrated up-down
counter. Every cycle, it is incremented or decremented depending if the current logic detects
the limit condition or not. The limit condition is the peak drain current, I
Table 8 on page 7
Figure 13 on page
After the reset of the counter, if the peak drain current is continuously equal to the level I
the counter will be incremented till the fixed time, t
MOSFET switch ON. It will be activated again, through the soft start, after the t
Figure 26 on page 17
see the
In case of overload or short-circuit event, the power MOSFET switching will be stopped after
a time that depends from the counter and that can be as maximum equal to t
protection will occur in the same way until the overload condition is removed, see
on page
17.
This protection ensures restart attempts of the converter with low repetition rate, so that it
works safely with extremely low power throughput and avoiding the IC overheating in case of
repeated overload events.
If the overload is removed before the protection tripping, the counter will be decremented
cycle by cycle down to zero and the IC will not be stopped.
Figure 26. Timing diagram: OLP sequence
SHORT CIRCUIT
V
OCCURS HERE
DD
V
DDon
V
DDCSon
I
DRAIN
I
Dlim_bm
*
t
1
* The time t
Automatic auto restart after overload or short-circuit
or the one set by the user through the R
9.
and the mentioned time values on
t
OVL
t
t
RESTART
RESTART
t
SS
can be lower or equal to the time t
1
OVL
Doc ID 17736 Rev 2
reported on
Dlim ,
resistor, as reported in
LIM
, after that will be disabled the power
OVL
RESTART
Table 8 on page
OVL
SHORT CIRCUIT
REMOVED HERE
t
OVL
t
RESTART
t
t
SS
SS
,
Dlim
time,
7.
. The
Figure 26
time
time
17/25