VNF1248F datasheet(37/79 Pages) STMICROELECTRONICS

37 / 79 page

10.1

NVM – Programmable default configuration

As mentioned previously, the device foresees the possibility to store, inside the NVM memory, a default

configuration for some key device parameters, critical from an operational/safety viewpoint, to be loaded only

when the device switches to fail-safe or locked states, to ensure a well-known, and not modifiable behavior in

such states; as soon as the device exits from them, parameter values are set back to the current setting stored

inside programmable RAM configuration registers, restoring the latest user configuration.

Loading of default settings is configurable by a specific bit (NVM_DEF_CFG_EN), accessible through CR#1, and

stored into NVM; modification of this bit shall be performed during device configuration by the user, while defining

the proper default setting, it is not recommended to do that during device operation in the application.

The following table summarizes the key device parameters equipped with NVM default configuration and stored

into correspondent memory sector #5:

Table 30. NVM mapped configuration parameters

Name

Description

Use

DIN_CTRL_EN_DEF

Direct input control enable

CR#1→DIN_CTRL_EN

Locked

DIN_CTRL_OPT_DEF

Direct input control behavior selection

(AND/OR modes)

CR#1→DIN_CTRL_OPT

Locked

BYPASS_CTL_DEF

Internal bypass control

CR#1→BYPASS_CTL

Fail-safe/Standby

FS_MODE_DEF

Output behavior configuration in fail-safe

CR#1→FS_MODE

Fail-safe

NVM_DEF_CFG_EN

Fail-safe default configuration enable

CR#1→NVM_DEF_CFG_EN

Fail-safe/Locked

T_NOM_FS_DEF

I2t fuse emulation nominal timescale

CR#2→TNOM

Fail-safe/Locked

OVC_THR_FS_DEF

I2t fuse emulation nominal overcurrent

protection threshold selection

CR#2→OVC_THR

Fail-safe/Locked

HSC_THR_FS_DEF

Hard short protection threshold selection

CR#2 →HSC_THR

Fail-safe/Locked

VDS_THRS_FS_DEF

VDS protection threshold selection

CR#2→VDS_THRS

Fail-safe/Locked

NTC_THR_FS_DEF

NTC thermal protection threshold selection

CR#3→NTC_THR

Fail-safe/Locked

WD_TIME_DEF

Watchdog monitor timeout selection

CR#3→WD_TIME

Fail-safe/Locked

UV_THR_DEF

Vs undervoltage threshold selection

CR#3→UV_THR

Fail-safe/Locked

CS_UV_RETRY_T_DEF

Current sense undervoltage protection

retry time

CR#3→CS_UV_RETRY_T

Fail-safe/Locked

CCM_VOUT_THR_DEF

Capacitive load charge (burst mode) VOUT

threshold selection

CR#3→CCM_VOUT_THR

Fail-safe/Locked

CCM_PWM_TON_MF_DEF

Capacitive load charge (burst mode) PWM

ton multiplying factor

CR#3→CCM_PWM_TON_MF Fail-safe/Locked

CCM_PWM_TON_DEF

Capacitive load charge (burst mode) PWM

ton setting

CR#5→CCM_PWM_TON

Fail-safe/Locked

CCM_PWM_T_DEF

Capacitive load charge (burst mode) PWM

period

CR#5→CCM_PWM_T

Fail-safe/Locked

CCM_PWM_SC_T_DEF

Capacitive load charge (burst mode) PWM

period for short circuit check at start

CR#5→CCM_PWM_SC_T

Fail-safe/Locked

CCM_PWM_SC_T_NB_DEF

Capacitive load charge (burst mode) max

number of PWM pulses for short circuit

check at start

CR#5→CCM_PWM_SC_T_NB Fail-safe/Locked

CCM_TIMEOUT_DEF

Capacitive load charge (burst mode)

maximum time duration

CR#5→CCM_TIMEOUT

Fail-safe/Locked

VNF1248F

Non-volatile memory (NVM) customer programming

DS14109 - Rev 7

page 37/79

VNF1248F Datasheet(PDF) 37 Page - STMicroelectronics

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