VIPER37HE STMicroelectronics, VIPER37HE Datasheet - Page 22

• Manufacturer Part Number: VIPER37HE
• Description: AC/DC Switching Converters ViperPlus Fixed Freq 800V 30mQ 265 Vac
• Manufacturer: STMicroelectronics
• Type: Off Line Switcherr

Specifications of VIPER37HE

• Product Category: AC/DC Switching Converters
• Rohs: yes
• Input / Supply Voltage (max): 23.5 V
• Input / Supply Voltage (min): 8.5 V
• Switching Frequency: 115 kHz
• Supply Current: 3.5 mA
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: Through Hole
• Package / Case: SDIP-10
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 25 C
• Number Of Outputs: 1
• Output Power: 25 W

Operation description
8.4
8.5
22/35
Figure 26. Timing diagram: soft-start
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
to the IC interrupted and consequently the V
V
power down completed. This feature is useful to prevent the 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 is activated only when the V
threshold (see
capacitor charging only when the V
described above is, for instance, a power down because of a fault condition. After a fault
condition, the charging current I
startup converter phase. This feature, together with the low V
ensures that, after a fault, the restart attempts of the IC have a very long repetition rate and
the converter works safely with extremely low power throughput.
behavior after a short-circuit event.
IN
is lower than V
DDoff
V
V
FBolp
FBlin
I
Dlim
threshold (see
V FB
I DRAIN
Table 7
DRAIN_START
). This means that the HV startup current generator restarts the V
Table 7
Doc ID 022218 Rev 1
(see
DDch
t ss
) the Power MOSFET is switched OFF, the energy transfers
DD
Table 7
is 0.6 mA (typ.) instead of the 3 mA (typ.) of a normal
IN
voltage drops below V
is higher than V
), the startup sequence is inhibited and the
DD
voltages decrease,
DD
DD
voltage drops below the V
voltage drops and when it falls below
DRAIN_START,
DD(RESTART)
DD(RESTART)
Figure 27
Figure 25
the startup sequence
. The scenario
threshold,
shows the IC
. Later, if the
DD(RESTART)
VIPER37
t
t
DD