Status
Condition
Action
Normal
Current()
>
OCD:Threshold
SafetyAlert()[OCD]
= 0
Alert
Current()
≤
OCD:Threshold
SafetyAlert()[OCD]
= 1
Trip
Current()
continuous ≤
OCD:Threshold
for
OCD:Delay
duration
SafetyAlert()[OCD1]
= 0
SafetyStatus()[OCD]
= 1
BatteryStatus()[TDA]
= 0
OperationStatus()[XDSG]
= 1
Recovery
[SafetyStatus()[OCD]
= 1 AND
Current()
continuous ≥
OCD:Recovery Threshold
for
OCD:Recovery Delay
time
SafetyStatus()[OCD]
= 0
BatteryStatus()[TDA]
= 0
OperationStatus()[XDSG]
= 0
2.6 Hardware-Based Protection
The BQ28Z610-R2 device has three main hardware-based protections—AOLD, ASCC, and ASCD1,2—with
adjustable current and delay time. Setting
AFE Protection Configuration[RSNS]
divides the threshold value
in half. The
Threshold
settings are in mV; therefore, the actual current that triggers the protection is based on
the R
SENSE
used in the schematic design (see the
BQ28Z610-R1 1-Cell to 2-Series Cell Li-Ion Battery Pack
).
In addition, setting the
AFE Protection Configuration[SCDDx2]
bit provides an option to double all of the
SCD1,2 delay times for maximum flexibility towards the application's needs.
For details on how to configure the AFE hardware protection, refer to the tables in
.
All of the hardware-based protections provide a short term Trip/Recovery protection to account for a current
spike. The fault protection detects current spikes and after a delay time will turn OFF both FETs. Then with a
delay up to 250 ms, the non-appropriate FET associated with the fault condition will turn back ON. The recovery
method is a timer-based recovery set in
Protections.
Generally, when a fault is detected after the
Delay
time, both CHG and DSG FETs will be disabled (Trip stage).
Since both FETs are off, the current will drop to 0 mA. After
Recovery
time, the CHG FET or DSG FET will be
turned on again (Recovery stage) based on the fault condition.
The Trip/Recovery are documented in each of the following hardware-based protection sections.
Note
There is no PRES pin on the BQ28Z610-R2 device.
2.6.1 Overload in Discharge Protection
The device has a hardware-based overload in discharge protection with adjustable current and delay.
Status
Condition
Action
Normal
Current()
> (
AOLD Threshold[3:0]
/R
SENSE
)
SafetyAlert()[AOLD]
= 0
Trip
Current()
continuous ≤ (
AOLD Threshold[3:0]
/R
SENSE
) for
AOLD
Threshold[7:4]
duration
SafetyStatus()[AOLD]
= 1
OperationStatus()[XDSG]
= 1
Recovery
SafetyStatus()[AOLD]
= 1 for
OLD:Recovery
time
SafetyStatus()[AOLD]
= 0
OperationStatus()[XDSG]
= 0
2.6.2 Short Circuit in Charge Protection
The device has a hardware-based short circuit in charge protection with adjustable current and delay.
Status
Condition
Action
Normal
Current()
> (
ASCC Threshold[2:0]
/R
SENSE
)
SafetyAlert()[ASCC]
= 0
Trip
Current()
continuous ≤ (
ASCC Threshold[2:0]
/R
SENSE
) for
ASCC
Threshold[7:4]
duration
SafetyStatus()[ASCC]
= 1
BatteryStatus()[TCA]
= 1
OperationStatus()[XCHG]
= 1
Protections
SLUUCO0 – APRIL 2022
BQ28Z610-R2
15
Copyright © 2022 Texas Instruments Incorporated
