VIPER37LE STMicroelectronics, VIPER37LE Datasheet - Page 29

• Manufacturer Part Number: VIPER37LE
• Description: AC/DC Switching Converters ViperPlus Fixed Freq 800V 30mQ 265 Vac
• Manufacturer: STMicroelectronics
• Type: Off Line Switcherr

Specifications of VIPER37LE

• Product Category: AC/DC Switching Converters
• Input / Supply Voltage (max): 23.5 V
• Input / Supply Voltage (min): 8.5 V
• Switching Frequency: 60 kHz
• Supply Current: 2.5 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

VIPER37
8.12
Figure 32. Burst mode timing diagram, light load management
Brownout protection
Brownout protection is a not-latched shutdown function activated when a condition of mains
undervoltage is detected.
The brownout comparator is internally referenced to V
the voltage applied at the BR pin is below this internal reference. Under this condition the
Power MOSFET is turned off. Until the brownout condition is present, the VDD voltage
continuously oscillates between the V
diagram of
The switching operation is restarted as the voltage on the pin is above the reference plus the
previously mentioned voltage hysteresis, see
The brownout comparator is provided also with a current hysteresis, I
set the rectified input voltage above which the Power MOSFET starts switching after
brownout event, V
switched off, V
separately.
Figure 33
INoff
INon
. Thanks to the I
. A voltage hysteresis is present to improve the noise immunity.
, and the rectified input voltage below which the Power MOSFET is
Doc ID 022218 Rev 1
BRhyst
DDon
, see
and the UVLO thresholds, as shown in the timing
Figure 5
Table 8
, these two thresholds can be set
BRth
.
,
Table 8
, and disables the PWM if
Operation description
BRhyst
. The user must
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