STMEC001

Power states

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4

Power states

The STMEC001 operates in a number of states, as described in the following table:

4.1

Power states description

●

are grounded

●

outputs are grounded

●

USB/PW enable mode: when all 3 inputs are available, detection of cartd insertion

turns on all 3 outputs.

–

of the power switch prior to a card being inserted. Power to the card is based on

the state of /CPUSB and /CPPE (see table).

–

The card is present and VIN_1.5 V or/and VIN_3.3 V is removed from the input of

VIN_3.3 V will be disabled (see table). If power to VIN_1.5 V and VIN_3.3 V is

restored, output to the card will be restored.

–

VIN_1.5 V are not available; no power is made available to the card. If VIN_1.5 V

and VIN_3.3 V are made available at the input of the power switch after the card is

inserted, both VO_3.3 V and VO_1.5 V are made available to the card.

–

Standy mode: when all 3 supplies are available and /STBY is asserted. Only

–

VIN_1.5 V or/and VIN_3.3 V must not be present.

Table 5.

Power states

Voltage inputs

Outputs

Mode

3.3 V

1.5 V

/SHDN

/CPUSB

/CPPE

/STBY

3.3 V

1.5 V

ON

X

X

1

1

1

X

GND

GND

GND

No card

ON

X

X

0

X

X

X

GND

GND

GND

Shutdown

ON

ON

ON

1

0

X

1

ON

ON

ON

USB enable

ON

ON

ON

1

X

0

1

ON

ON

ON

PE enable

ON

ON

ON

1

X

X

0

ON

OFF

OFF

Standby

OFF

X

X

X

X

X

X

OFF

OFF

OFF

OFF