VIPER17 STMicroelectronics, VIPER17 Datasheet - Page 19

• Manufacturer Part Number: VIPER17
• Description: VIPerPlus family: fixed frequancy high performance off line high voltage converter
• Manufacturer: STMicroelectronics

VIPER17
Equation 3
Where:
●
●
●
●
●
●
●
Than, fixed R
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
COUNTER
COUNTER
COUNTER
COUNTER
STATUS
STATUS
STROBE
STROBE
RESET
RESET
V CONT
FAULT
FAULT
V AUX
V
OVP
OVP
OVP
V
V
N
N
V
V
R
OVP
OUT OVP
DSEC
DAUX
AUX
SEC
OVP
0
0
0
0
is the OVP threshold (see
N
N
is the auxiliary winding turns
is the secondary winding turns
together R
O
O
is the auxiliary diode forward voltage
is the secondary diode forward voltage
R
R
M
M
LIM,
A
A
2 µs
2 µs
L
L
is the converter output voltage value to activate the OVP (set by designer)
O
O
0
0
P
P
E
E
according to the desired I
R
R
A
A
T
T
O I
O I
N
N
LIM
0.5 µs
0.5 µs
0
0
make the output voltage divider
0 →1
0 →1
Doc ID 14419 Rev 7
T
T
E
E
M
M
P
P
O
O
R
R
R
A
A
OVP
k
R
R
Y
Y
OVP
Table 8 on page
1 →2
1 →2
D
D
S I
S I
T
T
=
U
U
R
R
=
B
B
R
A
A
DLIM
N
N
--------------------------------- -
R
LIM
2 →0
2 →0
C
C
E
E
LIM
, the R
R
×
+
LIM
1 k
---------------------- -
R
–
k
OVP
OVP
0
0
OVP
8)
OVP
can be calculating by:
0 →1
0 →1
F
F
E
E
E
E
D
D
B
B
A
A
1 → 2
1 → 2
C
C
Operation descriptions
K
K
L
L
O
O
O
O
P
P
F
F
A
A
L I
L I
2 →3
2 →3
U
U
R
R
E
E
3 → 4
3 → 4
19/31
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t