BQ3055_14 Datasheet, PDF (15/27 Pages) Texas Instruments – 2-Series, 3-Series, and 4-Series Li-Ion Battery Pack Manager

bq3055
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• Lifetime Maximum Battery Cell Voltage
• Lifetime Minimum Battery Cell Voltage
SLUSA91B – OCTOBER 2010 – REVISED OCTOBER 2013
Authentication
• The bq3055 supports authentication by the host using SHA-1.
• SHA-1 authentication by the gas gauge is required for unsealing and full access.
Power Modes
The bq3055 supports three power modes to reduce power consumption:
• In Normal Mode, the bq3055 performs measurements, calculations, protection decisions, and data updates in
0.25-second intervals. Between these intervals, the bq3055 is in a reduced power stage.
• In Sleep Mode, the bq3055 performs measurements, calculations, protection decisions, and data updates in
adjustable time intervals. Between these intervals, the bq3055 is in a reduced power stage. The bq3055 has
a wake function that enables exit from Sleep mode when current flow or failure is detected.
• In Shutdown Mode, the bq3055 is completely disabled.
Configuration
Oscillator Function
The bq3055 fully integrates the system oscillators and does not require any external components to support this
feature.
System Present Operation
The bq3055 checks the PRES pin periodically (1s). If PRES input is pulled to ground by the external system, the
bq3055 detects this as system present.
2-, 3-, or 4-Cell Configuration
In a 2-cell configuration, VC1 is shorted to VC2 and VC3. In a 3-cell configuration, VC1 is shorted to VC2.
Cell Balancing
The device supports cell balancing by bypassing the current of each cell during charging or at rest. If the device's
internal bypass is used, up to 10 mA can be bypassed and multiple cells can be bypassed at the same time.
Higher cell balance current can be achieved by using an external cell balancing circuit. In external cell balancing
mode, only one cell at a time can be balanced.
The cell balancing algorithm determines the amount of charge needed to be bypassed to balance the capacity of
all cells.
Internal Cell Balancing
When internal cell balancing is configured, the cell balance current is defined by the external resistor R_VC at the
VCx input.
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