For the firmware settings needed for the design
requirements, refer to the BQ28Z620 Technical Reference Manual.
- To set the 2s1p battery pack, go to data flash Configuration: DA Configuration register's bit 0 (CC0) = 1.
- To set design capacity, set the data flash value to 4400 in the Gas Gauging: Design: Design Capacity register.
- To set device chemistry, go to data flash
SBS Configuration: Data: Device Chemistry. The
BQStudio
software automatically populates the correct chemistry identification. This
selection is derived from using the
BQChem
feature in the tools and choosing the option that matches the device chemistry
from the list.
- To protect against cell overvoltage, set the data flash value to 4300 in Protections: COV: Standard Temp.
- To protect against cell undervoltage, set the data flash value to 2500 in the Protections: CUV register.
- To set the shutdown voltage to prevent further pack depletion due to low pack voltage, program Power: Shutdown: Shutdown voltage = 2300.
- To protect against large charging currents when the AC adapter is attached, set the data flash value to 6000 in the Protections: OCC: Threshold register.
- To protect against large discharging currents when heavy loads are attached, set the data flash value to –6000 in the Protections: OCD: Threshold register.
- Program a short circuit delay timer and threshold setting to enable the operating the system for large short transient current pulses. These two parameters are under Protections: ASCC: Threshold = 100 for charging current. The discharge current setting is Protections: ASCD:Threshold = –100 mV.
- To prevent the cells from overcharging and adding a second level of safety, there is a register setting that will shut down the device if any of the cells voltage measurement is greater than the Safety Over Voltage setting for greater than the delay time. Set this data flash value to 4500 in Permanent Fail: SOV: Threshold.
- To disable the cell balancing feature, set the data flash value to 0 in Settings: Configuration: Balancing Configuration: bit 0 (CB).
- To enable the internal temperature and the external temperature sensors: Set Settings:Configuration: Temperature Enable: Bit 0 (TSInt) = 1 for the internal sensor; set Bit 1 (TS1) = 1 for the external sensor.
- To prevent charging of the battery pack if the temperature falls below 0°C, set Protections: UTC:Threshold = 0.
- To prevent discharging of the battery pack if the temperature falls below 0°C, set Protections: UTD:Threshold = 0.
- To provide required information to the smart chargers, the gas gauge must operate in BROADCAST mode. To enable this, set the [BCAST] bit in Configuration: SBS Configuration 2: Bit 0 [BCAST] = 1.
Each parameter listed for fault trigger thresholds
has a delay timer setting associated for any noise filtering. These values, along
with the trigger thresholds for fault detection, may be changed based upon the
application requirements using the data flash settings in the appropriate register
stated in the
BQ28Z620
Technical Reference Manual.