Datasheet

VIPER27 Operation descriptions
Doc ID 15133 Rev 5 19/31
Where:
● V
OVP
is the OVP threshold (see Table 8 on page 7 )
● V
OUT OVP
is the converter output voltage value to activate the OVP set by designer
● N
AUX
is the auxiliary winding turns
● N
SEC
is the secondary winding turns
● V
DSEC
is the secondary diode forward voltage
● V
DAUX
is the auxiliary diode forward voltage
● R
OVP
together R
LIM
make the output voltage divider
Than, fixed R
LIM,
according to the desired I
Dlim
, the R
OVP
can be calculating by:
Equation 4
The resistor values will be such that the current sourced and sunk by the CONT pin be
within the rated capability of the internal clamp.
Figure 26. OVP timing diagram
R
OVP
R
LIM
1k
OVP
–
k
OVP
-----------------------
×=
t
V
DS
V
AUX
t
t
t
STROBE
t
COUNTER
RESET
t
COUNTER
STATUS
t
0
V
CONT
2 µs
0.5 µs
OVP
FAULT
0 0 0
0
→
11
→
22
→
0
0
→
11
→
22
→
3 3
→
4
0
ERULIAF POOL KCABDEEFECNABRUTSID YRAROPMETNOITAREPO LAMRON
t
V
DS
V
OVP
t
t
t
STROBE
t
COUNTER
RESET
t
COUNTER
STATUS
t
0
2 µs
0.5 µs
OVP
FAULT
0 0 0
0
→
11
→
22
→
0
0
→
11
→
22
→
3 3
→
4
0
ERULIAF POOL KCABDEEFECNABRUTSID YRAROPMETNOITAREPO LAMRON
t