VIPER17HN STMicroelectronics, VIPER17HN Datasheet - Page 17

• Manufacturer Part Number: VIPER17HN
• Description: IC OFFLINE CONV PWM OVP OCP 8DIP
• Manufacturer: STMicroelectronics
• Series: VIPer™ plusr

Specifications of VIPER17HN

• Output Isolation: Isolated
• Frequency Range: 103 ~ 127kHz
• Voltage - Input: 8.5 ~ 23.5 V
• Voltage - Output: 800V
• Power (watts): 12W
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 8-DIP (0.300", 7.62mm), 7 Leads
• Output Voltage: 800 V
• Output Power: 1 W
• Input Voltage: - 0.3 V
• Switching Frequency: 115 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: Through Hole
• Duty Cycle (max): 80 %
• Number Of Outputs: 1
• For Use With: 497-9050 - BOARD DEMO BASED ON VIPER17HN497-9007 - BOARD EVAL BASED ON VIPER17497-8513 - BOARD EVAL VIPER17HN 6W SMPS497-8250 - BOARD EVAL FOR VIPER17497-6447 - BOARD EVAL FOR VIPER17L497-6446 - BOARD EVAL FOR VIPER17H
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6950-5; VIPER17HN

VIPER17
7.4
7.5
Power down operation
At converter power down, the system loses regulation as soon as the input voltage is so low
that the peak current limitation is reached. The V
the V
energy transfers to the IC interrupted and consequently the V
Figure 23 on page
the start up sequence is inhibited and the power down completed. This feature is useful to
prevent converter’s restart attempts and ensures monotonic output voltage decay during the
system power down.
Auto restart operation
If after a converter power down, the V
is not inhibited and will be activated only when the V
V
generator restarts the V
V
fault condition. After a fault condition, the charging current, I
the 3 mA (typ.) of a normal start up converter phase. This feature together with the low
V
long repetition rate and the converter works safely with extremely low power throughput.
The
Figure 25. Timing diagram: behavior after short circuit
DD(RESTART)
DD(RESTART)
DD(RESTART)
Figure 25
DDoff
threshold (see
. The scenario above described is for instance a power down because of a
threshold (see
threshold ensures that, after a fault, the restart attempts of the IC has a very
shows the IC behavioral after a short circuit event.
16. Later, if the V
DD
Table 7 on page
capacitor charging only when the V
Table 7 on page
Doc ID 14419 Rev 7
IN
IN
is lower than V
is higher than V
6) the power MOSFET is switched OFF, the
6). This means that the HV start up current
DD
voltage drops and when it falls below
DD
DRAIN_START
voltage drops down the
DRAIN_START,
DDch
DD
DD
, is 0.6 mA (typ.) instead of
voltages decreases,
voltage drops below
(see
Operation descriptions
the start up sequence
Table 7 on page
17/31
6),