VIPER16HD STMicroelectronics, VIPER16HD Datasheet - Page 18

• Manufacturer Part Number: VIPER16HD
• Description: IC OFFLINE CONV PWM OTP 16-SOIC
• Manufacturer: STMicroelectronics
• Series: VIPer™ plusr

Specifications of VIPER16HD

• Output Isolation: Either
• Frequency Range: 103 ~ 127kHz
• Voltage - Input: 11.5 ~ 23.5 V
• Voltage - Output: 800V
• Power (watts): 12W
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Output Power: 1 W
• Input Voltage: 3.3 V
• Switching Frequency: 115 KHz
• Mounting Style: SMD/SMT
• Duty Cycle (max): 80 %
• For Use With: 497-9006 - BOARD EVAL BASED ON VIPER16497-8836 - EVAL BOARD FOR VIPER16HD497-8835 - EVAL BOARD FOR VIPER16HD ISO PSU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Open loop failure protection
15
18/24
Open loop failure protection
In case the power supply is built in fly-back topology and the VIPer16 is supplied by an
auxiliary winding, as shown in
converter is protected against feedback loop failure or accidental disconnections of the
winding.
The following description is applicable for the schematics of
Figure 28 on page
If R
voltage, V
output through the secondary-to-auxiliary turns ratio.
As the auxiliary voltage increases up to the internal V
reported on
latch threshold, I
generated.
In order to distinguish an actual malfunction from a bad auxiliary winding design, both the
above conditions (drain current equal to the drain current limitation and current higher than
I
If R
voltage V
case of isolated fly-back).
Figure 27. FB pin connection for non-isolated fly-back
DDol
H
L
is opened or R
through VDD clamp) have to be verified to reveal the fault.
is opened or R
REF_FB
OUT
Table 8 on page
, will increase and so the auxiliary voltage, V
R
R
H
L
DDol
(in case of non isolated fly-back) or to the external TL voltage reference (in
V
OUT
19, respectively the non-isolated fly-back and the isolated fly-back.
L
H
(the value is reported on
is shorted, the VIPer16 works at its drain current limitation. The output
is shorted, the output voltage, V
FB
C
VDD
7) and the clamp current injected on VDD pin exceeds the
V
Doc ID 15232 Rev 4
REF_FB
Figure 27 on page 18
VDD
-
+
E/A
C
COMP
P
BUS
Table 8 on page
R
C
S
S
nR
V
from R
COMPL
and
DD
R
OUT
SENSE
+
-
+
-
active clamp, V
Figure 28 on page
, will be clamped to the reference
AUX
Figure 27 on page 18
, which is coupled with the
PWM stop
to PWM
7), a fault signal is internally
R
AUX
DDclamp
D
AUX
19, the
(the value is
and
VIPER16
V
AUX