VIPER26 STMicroelectronics, VIPER26 Datasheet - Page 17

• Manufacturer Part Number: VIPER26
• Description: VIPerPlus family: fixed frequency high performance off line high voltage converter
• Manufacturer: STMicroelectronics

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
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
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
V
I
Dlim_bm
DDCSon
V
I
DRAIN
V
DDon
DD
Figure 26 on page 17
17.
* The time t
SHORT CIRCUIT
OCCURS HERE
t
1
*
1
can be lower or equal to the time t
or the one set by the user through the R
9.
t
RESTART
and the mentioned time values on
Doc ID 17736 Rev 2
t
SS
t
Automatic auto restart after overload or short-circuit
OVL
OVL
t
RESTART
OVL
, after that will be disabled the power
t
SS
t
OVL
LIM
resistor, as reported in
SHORT CIRCUIT
REMOVED HERE
Table 8 on page
t
RESTART
Dlim ,
reported on
t
SS
OVL
RESTART
. The
Figure 26
7.
time
time
time,
17/25
Dlim
,