AN4116 Datasheet, PDF (1/38 Pages) STMicroelectronics – This document describes a 12 V-350 mA power supply

AN4116
Application note
STEVAL-ISA112V1: 12 V/4 W, 115 kHz non-isolated flyback
By Mirko Sciortino
Introduction
This document describes a 12 V-350 mA power supply set in non-isolated flyback topology
with the VIPER06, a new offline high voltage converter by STMicroelectronics.
The features of the device are:
■ 800 V avalanche rugged power section
■ PWM operation at 115 kHz with frequency jittering for lower EMI
■ limiting current with adjustable set point
■ onboard soft-start
■ safe auto-restart after a fault condition (overload, short-circuit)
The VIPER06 does not require a biasing circuit to operate because the IC can be supplied
by an internal current generator, therefore saving the cost of the transformers auxiliary
winding. If the device is biased through an auxiliary winding, the demonstration board can
reach very low standby consumption (< 30 mW at 230 V_AC, with output load disconnected).
Both cases are treated in the present document. The available protections are: thermal
shutdown with hysteresis, delayed overload protection, open loop failure protection (the last
is available only if self-biasing is excluded).
Figure 1. Demonstration board image
January 2013
STEVAL-ISA112V1
Doc ID 023220 Rev 1
1/38
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