L9961 datasheet(31/63 Pages) STMICROELECTRONICS

31 / 63 page

Symbol

Parameter

Test conditions

Min.

Typ.

Max.

Unit

VOVCDCHGTH

=128VCUR_RES*CODE

VPERSIST_OVC_TH

Programmable persistent

overcurrent threshold (8 bit).

Check is performed on the current

absolute value.

VPERSISTOVTH

=VCUR_RES*CODE

Tested by SCAN

255*VCUR_RES

Note:

Note: accuracy of the thresholds depends on the accuracy of the CSA. Refer to Table 20.

3.5.4

Short-circuit in discharge protection

When the CSA is enabled, L9961 protects the battery pack from short-circuit in discharge by sensing the

current through the shunt resistor with a faster filter time TSC_FILTER, programmable in the SC_FILTER field.

This diagnostic is enabled using SC_EN bit and covers the failures listed in Table 22.

Writing SC_EN = 1 enables the short-circuit monitor after a maximum delay of 528 μs. To avoid false detections,

overcurrent thresholds shall only be modified while SC_EN = 0

Table 22. Short-circuit in discharge diagnostics

Fault type

Assertion condition

IC reaction to

assertion

Release

condition

IC reaction to flag

clear

Maskable

Short-circuit in

discharge

If the (ISENSEP –

ISENSEM) voltage

raises above VSC_TH

for longer than

TSC_FILTER, the SC

fault is acknowledged.

The SC_DCHG flag is

set

If the If the

(ISENSEP –

ISENSEM)

voltage falls

below VSC_TH

for longer

than

TSC_FILTER,

the

SC_DCHG

flag can be

cleared by

MCU

The Discharge FET

is restored to the

status defined by the

DCHG_ON bit

CSA_EN masks

measurement

execution. When

disabled, the

SC_DCHG flag can

always be cleared

The Discharge FET is

turned OFF

FAULTN line is

released

SC_EN masks

diagnostic execution.

When disabled, the

SC_DCHG flag can

always be cleared

FAULTN line is

asserted

SC_DCHG_PRDRV_M

SK masks reaction on

DCHG pin

SC_DCHG_FAULTN_

MSK masks reaction

on FAULTN pin

Persistent short-circuit

in discharge

If the DCHG FET

is OFF (either

commanded by user

or forced by

diagnostics) and the

ISENSEP – ISENSEM

voltage raises above

VPERSIST_SC_TH, the

PERSIST_SC_DCHG

fault is acknowledged.

Diagnostic is masked

for TPERSIST_SC_BLANK

starting from DCHG

FET OFF event.

The

PERSIST_SC_DCHG

flag is set

If the If the

(ISENSEP –

ISENSEM)

voltage falls

below

VPERSIST_SC_

TH for longer

than

TSC_FILTER,

the

PERSIST_SC

_DCHG flag

can be

cleared by

MCU

FUSE pre-driver is

disabled

CSA_EN masks

measurement

execution. When

disabled, the

PERSIST_SC_DCHG

flag can always be

cleared

FUSE pre-driver is

enabled

FAULTN line is

released

SC_EN masks

diagnostic execution.

When disabled, the

PERSIST_SC_DCHG

flag can always be

cleared

FAULTN line is

asserted

PERSIST_SC_DCHG_

FUSE_MSK masks

reaction on FUSE pin

L9961

Current conversion routine

DS14012 - Rev 1

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