External Override Permanent Fail
40
SLUUBD3D – September 2015 – Revised September 2018
Copyright © 2015–2018, Texas Instruments Incorporated
Permanent Fail
Status
Condition
Action
Normal
DSG FET off AND
Current()
>
DFET:OFF Threshold
PFAlert()[DFETF]
= 0
Alert
DSG FET off AND
Current()
≤
DFET:OFF Threshold
PFAlert()[DFETF]
= 1
Trip
DSG FET off AND
Current()
continuously
≤
DFET:OFF
Threshold
for
DFET:OFF Delay
duration
PFAlert()[DFETF]
= 0
PFStatus()[DFETF]
= 1
BatteryStatus()[TCA]
= 1
BatteryStatus()[TDA]
= 1
Class
Subclass
Name
Type
Min
Max
Default
Unit
Permanent Fail
DFET
OFF Threshold
I2
–500
0
–5
mA
Permanent Fail
DFET
Delay
U1
0
255
5
s
4.13 External Override Permanent Fail
The device can detect an external override signal sent to the companion bq769x0 AFE, which can cause
permanent failure of the battery. This can be used to indicate to the bq78350-R1 that an external circuit,
such as an independent voltage protection circuit, has disabled the battery permanently.
Status
Condition
Action
Normal
AFESysStat() [OVRD_ALERT]
= 0
PFAlert()[AFE_OVRD]
= 0
Alert
AFESysStat() [OVRD_ALERT]
= 1
PFAlert()[AFE_OVRD]
= 1
Trip
AFESysStat() [OVRD_ALERT]
= 1 continuously for
AFE
External Override: Delay
duration
PFAlert()[AFE_OVRD]
= 0
PFStatus()[AFE_OVRD]
= 1
Class
Subclass
Name
Type
Min
Max
Default
Unit
Permanent Fail
AFE External Override
Delay
U1
0
255
5
s
4.14 AFE Register Permanent Fail
The device compares the AFE hardware register periodically with a RAM backup and corrects any errors.
If any errors are found during the check, the device increments the AFE register fail counter. If the
comparison fails too many times, the device disables the pack permanently.
Status
Condition
Action
Normal
AFE register fail counter = 0
PFAlert()[AFER]
= 0
Compare AFE register and RAM backup every
AFER:Compare Period
Alert
AFE register fail counter > 0
PFAlert()[AFER]
= 1
Decrement AFE register fail counter by one after
each
AFER:Delay Period
Compare AFE register and RAM backup every
AFER:Compare Period
Trip
AFE register fail counter
≥
AFER:Threshold
PFAlert()[AFER]
= 0
PFStatus()[AFER]
= 1
BatteryStatus()[TCA]
= 1
BatteryStatus()[TDA]
= 1
Class
Subclass
Name
Type
Min
Max
Default
Unit
Permanent Fail
AFER
Threshold
U1
0
255
100
counts
Permanent Fail
AFER
Delay Period
U1
0
255
2
s
Permanent Fail
AFER
Compare Period
U1
0
255
5
s