Data brief

For further information contact your local STMicroelectronics sales office.

January 2012

Doc ID 022688 Rev 1

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STEVAL-IFP021V1

5 V and 12 V power line protection based on STEF05

and STEF12 electronic fuses

Features

Description

The STEVAL-IFP021V1 demonstration board is

based on the STEF05 and STEF12 electronic

fuses (E-Fuses).

It is designed to help users evaluate the benefit of

the complete protection offered by the E-Fuse

family and to customize their own application.

The E-Fuse family of hot-swap converters is

designed to replace the mechanical fuses on low

voltage power lines.

The STEF05 and STEF12 are integrated

electronic fuses optimized for monitoring output

current and input voltage.

Connected in series to the 5 V/12 V rails, they are

capable of protecting the electronic circuitry on

the output from overcurrent and overvoltage.

The turn-on time is programmable by means of an

external capacitor, allowing control of the inrush

current at startup and during hot-swaps.

When an overload condition occurs, the E-Fuse

limits the output current to a predefined safe

value. If the anomalous overload condition

persists, it goes into an open state, disconnecting

the load from the power supply.

If a continuous short-circuit is present on the

board, when power is re-applied the E-Fuse

initially limits the output current to a safe value,

and then again goes into an open state.

Both devices are equipped with a thermal

protection circuit.

The intervention of the thermal protection is

signaled to the board monitoring circuits through

a signal on the enable/fault pin that can be

connected to other parts belonging to the same

family to cause a simultaneous shutdown during

failure events.

Unlike mechanical fuses, which must be

physically replaced after a single event, E-Fuses

do not degrade in their performance after short-

circuit/thermal protection interventions and can be

reset either by re-cycling the supply voltage or by

using the enable pin.

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