February 2012 Doc ID 022218 Rev 1 1/35
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VIPER37
VIPerPlus family: fixed frequency offline converter
Features
■ 800 V avalanche rugged power section
■ PWM operation with adjustable limiting current
■ 30 mW standby power at 265 Vac
■ Operating frequency:
– 60 kHz for L type
– 115 kHz for H type
■ Frequency jittering for low EMC
■ Output overvoltage protection
■ High primary current protection (2
nd
OCP)
■ Input undervoltage setting (brownout)
■ Onboard soft-start
■ Safe auto-restart after a fault condition
■ Hysteretic thermal shutdown
Applications
■ SMPS for set-top boxes, DVD players and
recorders, white goods
■ Auxiliary power supply for consumer and home
equipment
■ ATX auxiliary power supply
■ Low / medium power AC-DC adapters
Description
This device is an offline converter with an 800 V
rugged power section, a PWM control, two levels
of overcurrent protection, overvoltage and
overload protection, hysteretic thermal protection,
soft-start, and safe auto-restart after the removal
of any fault condition. Burst mode operation and
very low device consumption help to meet the
standby energy saving regulations.
Advance frequency jittering reduces EMI filter
costs. Brownout function protects the switch
mode power supply when the rectified input
voltage level is below the normal minimum level
specified for the system. The high voltage startup
circuit is embedded in the device.
Figure 1. Typical topology
SDIP10
DC input high voltage
wide range
+
DC Output voltage
-
+
VIPER37
DRAINDRAIN
DRAIN
DRAIN
DRAIN
BRVDD CONT FBGND
Table 1. Device summary
Order codes Package Packaging
VIPER37LE
SDIP10 Tube
VIPER37HE
www.st.com
