BQ2084-V133 Datasheet, PDF (16/64 Pages) Texas Instruments – SBS v1.1-COMPLIANT GAS GAUGE FOR USE WITH THE bq29312

bq2084-V133
SLUS640A – JUNE 2005 – REVISED JUNE 2005
www.ti.com
Alarm Broadcasts to Smart Charger and Host
If any of the bits 8-15 in BatteryStatus() are set, the bq2084-V133 broadcasts an AlarmWarning() message to the
Host address. If any of the bits 12-15 in BatteryStatus() are set, the bq2084-V133 also sends an AlarmWarning()
message to the Smart Charger address. The bq2084-V133 repeats the AlarmWarning() messages every 10
seconds until the alarm bits are cleared. All broadcasts can be disabled by setting SM (bit 2) in Pack
Configuration (DF 0x28).
Precharge Qualification
The bq2084-V133 sets ChargingCurrent() to the precharge rate as programmed in Precharge Current (DF
0x42-0x43) under the following conditions:
• Voltage: The bq2084-V133 requests the precharge charge rate when any cell voltage drops below the
precharge threshold or when the EDV0 threshold is detected. Once requested, a precharge rate remains
until all cell voltages increase above the precharge threshold and the EDV0 condition does not exist. The
precharge threshold is programmed in Precharge Voltage (DF 0x3c-0x3d).
• Temperature: The bq2084-V133 requests the precharge rate when Temperature() is between Charge Inhibit
Temp Low (DF 0x46) and the precharge threshold programmed in Precharge Temp (DF 0x44).
Temperature() must be equal to or greater than the precharge threshold + 3°C to allow the fast-charge rate.
Charge Suspension
The bq2084-V133 may temporarily suspend charge if it detects a charging fault. A charging fault includes the
following conditions.
• Overcurrent: An overcurrent condition exists when the bq2084-V133 measures the charge current to be
greater than Charge OC Threshold (DF 0x12a-0x12b) for a time greater than Charge OC Time (DF 0x12c).
On detecting an overcurrent condition, the bq2084-V133 turns off the Charge FET. If the Nonremovable
Battery bit is not set in Misc Configuration (DF 0x2a), then the Discharge FET is turned off also. This
condition is cleared when the pack is removed or if the Nonremovable Battery bit is set in Misc Configuration
(DF 0x2a) and when a discharge current is detected or when SBS AverageCurrent() is less than the
ClearFailCurrent (DF 0x61-0x62) for FaultResetTime (DF 0x130).
• Overtemperature: During charging, an overtemperature condition exists when Temperature() is greater than
the Charge Suspend Temp High value programmed in DF 0x6d, 0x6e. On detecting an overtemperature
condition, if enabled by the OT bit in Misc Configuration (DF 0x2a), the bq2084-V133 turns off the Charge
and Discharge FETs. The overtemperature condition is cleared when Temperature() is equal to or below
Charge Suspend Temp High Reset (DF 0x6f-0x70). The condition is also cleared if the pack is removed.
• Undertemperature: During charging, an undertemperature condition exists when Temperature() is less than
the Charge Suspend Temp Low (DF 0x79) or Charge Inhibit Temp Low (DF 0x46). On detecting an
undertemperature condition the bq2084-V133 turns off the Charge FET. The undertemperature condition is
cleared when Temperature() is greater than Charge Suspend Temp Low DF 0x79. The condition is also
cleared if the pack is removed. The maximal value of Charge Suspend Temp Low setting is 12.7°C.
• Charging exceeds Maximum Charging Time (DF 0x10f-0x110). If charging time reaches Maximum Charge
Time, the Charge FET is turned off. This condition is cleared when the pack detects discharge current or is
removed.
• Cell or Pack Overvoltage: An overvoltage condition exist when any cell is greater than Cell Over Voltage
Limit (DF 0x63-0x64) or if Voltage() is greater than Charging Voltage (DF 0x3a-0x3b) plus
OvervoltageMargin (DF 0x5d-05e). This condition is cleared when the pack is removed or if the
Nonremovable Battery bit is set in Misc Configuration (DF 0x2a) and when a discharge current is detected or
when SBS AverageCurrent() is less than the ClearFailCurrent (DF 0x61-0x62) for FaultResetTime (DF
0x130). Also, the overvoltage conditon must be cleared by Voltage() less than Charging Voltage (DF
0x3a-0x3b) plus OvervoltageMargin (DF 0x5d-05e) and all cell voltages less than Cell Over Voltage Reset
(DF 0xe0-0xe1).
• Charging is also temporarily suspended during pulse-charging, but this is not considered a fault condition.
Pulse Charge
The bq2084-V133 is capable of charge control using a pulse-charging algorithm, which allows for charge control
in systems where the charger does not control current.
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