ST ISA014V1 User Manual

VIPer12A travel adaptor 3.6W output

Features

■ Switch mode general purpose power supply

■ Input: 85 to 264Vac @ 50/60Hz

■ Output: 6V @ 600mA

■ Output power : 3.6W

■ Switching frequency 60kHz

■ Current mode control

■ 65% efficiency

■ 9V to 40V wide range VDD voltage

■ Auxiliary undervoltage lockout with hysteresis

■ High voltage start up current source

■ Overtemperature, overcurrent and overvoltage

protection.

Reference design genaral
description

STEVAL-ISA014V1

Data Brief

STEVAL-ISA014V1

ST Components

■ VIPer12AS

■ SMBY01-200

The travel adaptor design presented here has
been made with the aim of minimizing overall cost
for a secondary voltage and current regulated
adapter topology widely used in cellular phone
adapters. Thanks to the VIPer12A low power
consumption, it is possible to achieve 100mW
standby power in a wide range of operations, as
recommended by the "European Comm ission of
Energy".

March 2006 Rev 1 1/5

For further information contact your local STMicroelectronics sales office

www.st.com

5

General circuit description STEVAL-ISA014V1

1 General circuit desc ript ion

The circuit is a standard fly-back converter with secondary current and voltage regulation
driving the VIPer12A feedback pin through an optocoupler.

The power losses are distributed at 6V / 600mA output power as follows:

● 400mW in the output diode

● 700mW in the VIPer12A

● 300mW in the transformer

● 380mW in the shunt resistor

Overall efficiency is 67%.
If the losses in the shunt resistor are considered as available power, the converter efficiency

becomes 74%. This is possible by using a secondary controller like ST's TSM101.
In standby, the demo board consumes less than 100mW at 100Vdc and 120mW at 380Vdc.
The major contribution to the standby consumption is the VIPer12A own consumption and is

independent from input voltage.

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