VIPERA16HD STMicroelectronics, VIPERA16HD Datasheet - Page 17

• Manufacturer Part Number: VIPERA16HD
• Description: AC/DC Switching Converters Fixed Freq VIPer 800V 115kHz Plus
• Manufacturer: STMicroelectronics

Specifications of VIPERA16HD

• Rohs: yes

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
equal to the level I
be disabled the power MOSFET switch ON. It will be activated again, through the soft start,
after the t
values on
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
and
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 25. Timing diagram: OLP sequence (IC externally biased)
Figure 26. Timing diagram: OLP sequence (IC internally biased)
V
Figure 26 on page
I
Dlim_bm
DDCSon
I
V
DRAIN
V
DDon
DD
V
I
Dlim_bm
DDCSon
I
V
DRAIN
RESTART
V
DDon
Table 8 on page
* The time t
DD
SHORT CIRCUIT
OCCURS HERE
* The time t
SHORT CIRCUIT
OCCURS HERE
t
1
*
1
t
time, see the
can be lower or equal to the time t
1
Dlim
or the one set by the user through the R
*
9. After the reset of the counter, if the peak drain current is continuously
1
can be lower than or equal to the time t
, the counter will be incremented till the fixed time, t
t
RESTART
17. This protection ensures restart attempts of the converter with low
t
RESTART
7.
Doc ID 15232 Rev 5
Figure 25
t
SS
t
SS
t
OVL
t
OVL
OVL
and
OVL
t
t
RESTART
RESTART
Figure 26 on page 17
t
SS
t
SS
t
OVL
t
OVL
LIM
resistor, as reported in
SHORT CIRCUIT
REMOVED HERE
t
SHORT CIRCUIT
REMOVED HERE
RESTART
t
RESTART
and the mentioned time
Dlim ,
t
OVL
SS
t
reported on
SS
OVL
, after that will
. The
time
time
Figure 25
time
time
17/25