BQ28Z560-R1 Datasheet, PDF (43/60 Pages) Texas Instruments – Single Cell Li-Ion Battery Gas Gauge and Protection

bq28z560-R1
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CHARGING AND CHARGE TERMINATION INDICATION
SLUSBD3 – APRIL 2013
Detection Charge Termination
For proper bq28z560-R1 operation, the cell charging voltage must be specified by the user. The default value for
this variable is in the data flash Charging Voltage.
The bq28z560-R1 detects charge termination when:
The battery current drops below the Taper Current for two consecutive Current Taper Window time periods
during charging AND battery voltage is equal to or higher than the Charging Voltage – Taper Voltage. Full
Charge is set when the taper condition is met.
Charge Inhibit
The bq28z560-R1 can indicate when battery temperature has fallen below or risen above predefined thresholds
Charge Inhibit Temp Low or Charge Inhibit Temp High. In this mode, the CHG_FET bit is set in the Control
register to indicate this condition, and is returned to its low state once battery temperature returns to the range
[Charge Inhibit Temp Low + Temp Hys, Charge Inhibit Temp High – Temp Hys]. This is implemented to
indicate that an action is required by the battery charger.
The charging should not start when the temperature is below the Charge Inhibit Temp Low or above the
Charge Inhibit Temp High.
The charge FET should not turn off when Temp > Chg Inhibit Temp during charging .
The gas gauge will enter CHARGE INHIBIT mode only if it is in DISCHARGE mode or RELAX mode and Temp >
Chg Inhibit Low. Then it will set the Charging Current and Charging Voltage values to 0.
POWER MODES
The bq28z560-R1 has four power modes: NORMAL, SLEEP, HIBERNATE, and SHUTDOWN. In NORMAL
mode, the bq28z560-R1 is fully powered and can execute any allowable task. In SLEEP mode, the gas gauge
exists in a reduced-power state, periodically taking measurements and performing calculations. In HIBERNATE
mode, the gas gauge is in a low power state, but can be awakened by communication or certain I/O activity. The
device enters SHUTDOWN mode if there is a BATLOW condition detected or power down of the system.
Figure 7 shows the relationship between these modes. The sections that follow describe the details.
Copyright © 2013, Texas Instruments Incorporated
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