General circuit description

STEVAL-ISA014V1

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General circuit description

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:

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400mW in the output diode

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700mW in the VIPer12A

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300mW in the transformer

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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.