VIPER17_0810 STMICROELECTRONICS [STMicroelectronics], VIPER17_0810 Datasheet - Page 20

• Manufacturer Part Number: VIPER17_0810
• Description: Off-line high voltage converters
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Operation descriptions
20/33
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
CONT
(pin 4)
(pin 4)
FAULT
FAULT
VAUX
V
V
3V
3V
OVP
OVP
DS
DS
V
V
designer
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
T
T
E
E
M
M
P
P
O
O
R
R
R
A
A
OVP
R
R
Y
Y
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
LIM
2 →0
2 →0
C
C
E
E
, the R
×
1 k
---------------------- -
–
k
OVP
0
0
OVP
9)
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
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
VIPER17
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t