VNF1048F datasheet(36/52 Pages) STMICROELECTRONICS

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Bit

Default

Name

Description

Access

VDS_MAX

External MOSFET desaturation shut-down: a desaturation shut-down of the

MOSFET (VDS_MAX = 1) and the bypass switch occurs if the VDS exceeds

the preset threshold when HS is in on-state after VDS_DEGLITCH time.

The MOSFET and the bypass switch are re-armed via SPI.

R/C

BYPASS_SAT

Low Current Bypass desaturation shut-down: a desaturation shut-down of the

Low Current Bypass (BYPASS_SAT = 1) occurs if the VDS exceeds the fixed

threshold when HS is in off-state and bypass is in on-state.

When BYPASS_SAT = 1, External MOSFET is automatically commanded on,

independently on OUTCTL bit value.

The Low Current Bypass is re-armed via SPI. A transition to WakeUp mode

causes this bit to be set to 1.

R/C

FUSE_LATCH

Current vs Time latch-off: an overcurrent shut-down of the MOSFET

(FUSE_LATCH = 1) and the bypass switch occurs when the current sense

voltage exceeds the preset threshold for longer than the preset time (I2-t

curve emulating a traditional fuse).

The MOSFET and bypass switch are re-armed via SPI.

R/C

OVC

Overcurrent warning: an overcurrent warning (OVC = 1) occurs even when

average current sense value evaluated in a time interval equal to tI_SAMPLING

(time basis used by fuse emulation algorithm) exceeds current threshold

programmed through OVC_THR.

This is a “real-time” bit

OVC bit keeps memory of the previous events: once this bit is set, it will be

reset automatically after a time depending on current level previously reached

and on the related timings.

Moreover, after a FUSE_LATCH bit setting, OVC will be automatically reset

in a time interval proportional to the TNOM value previously programmed

(provided that in the meantime FUSE_LATCH is not cleared, high side

restarts and current is again above OVC_THR).

Resetting FUSE_LATCH bit when OVC bit is still set to 1 is possible, but in

this case user can expect that trip time will be lower than expected.

DEV_OVT

Over-temperature shut-down (“real-time” bit). When DEV_OVT = 1, the

MOSFET, the charge pump and the bypass switch are turned off.

NTC_OVT

External MOS Over-Temperature: this bit is latched when NTC is lower than

NTC_THR. When NTC_OVT = 1 both External MOS and bypass switch are

turned off. The MOSFET and the bypass switch are re-armed via SPI.

R/C

VGS_LOW

This bit will be set in on-state when VGS falls below UV threshold

(VGS_UVLO_10V) for more than VG_UVLO_DEGLITCH. When this bit is set,

external FET is switched off.

R/C

CP_LOW

This bit will be set when VCP falls below VCP_LOW threshold for more than

tCP_RISE. When this bit is set, external FET driver is disabled. This is a “real-

time” bit.

WD_FAIL

Watchdog failure bit:

0: Watchdog OK;

1: Watchdog failure in Unlocked / Selftest states

When this bit is set, device goes to Locked state. To go back to the unlocked

mode through the GoToUnlocked sequence this bit must be cleared.

R/C

Parity Bit

Odd Parity Bit Check

VNF1048F

Status registers

DS13084 - Rev 6

page 36/52

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