7

Operating modes

7.1

State diagram

Figure 15. State diagram

GoToUnlocked SPI sequence

GoToUnlocked SPI sequence

WD_FAIL = 1 OR GSB_SPIE =1

OR HWLO_ST = 1 [1]

OR EN = 0 [3]

Wake-up

Unlocked

Locked

VS < VS_POR_OFF

VS > VS_POR_ON

Power-on

Standby

Self-test

t > tPWON

'OUTCTL' = 0

'RSTB' = 1

'BYPASSCTL' = 0

External FET is OFF

BYPASS is OFF

Control registers locked

Registers reset to default

BYPASS = 'BYPASSCTL'

I

S

= I

S_Q

External FET is OFF

SPI is not active

Registers as in previous state

I

SPI

= I

SPI STBY

'GOSTBY' = 0

BYPASS depends on test

External FET depends on test

SPI is active

External FET is ON

'DIAG' = 0

BYPASS is OFF

External FET is OFF

SPI is active

'WAKEUPM' = 1

Control registers locked

'BYPASS_SAT' = 1 (*)

External FET = 'OUTCTL'

BYPASS = 'BYPASSCTL'

'EN' =1 (**)

SPI is active

I

S

= I

S(ON)

External FET depends on

Control registers locked

'DIS_OUT_MODE',

BYPASS depends on

'DIS_OUT_MODE',

SPI is active

'EN' = 0 (***)

'LOCKEDM' = 1

(***) Transition to locked resets "EN" bit to 1 and sets 'DIS_OUT_FAULT' to 1 only if 'DIS_OUT_MODE' = 1.

(**) Transition to unlocked sets "EN' bit to 1.

(*) Transition to wakeup sets 'BYPASS_SAT' status bit to 1.

When there are more then one possibletransitions out of one state, priority number is indicated in brackets for each transition.

Notes:

7.2

Power-on mode

The power-on mode is the device reset state at VS power-on, due to device startup or power-on reset conditions.

At power-on, the registers are loaded with the default values and the RSTB is set to 1.

External FET, BYPASS switch, and charge pump are in the OFF state.

VNF1048F

Operating modes

DS13084 - Rev 8

page 37/49