The BQ76972 device has four operational modes to
support optimized features and power dissipation, with the device able to transition between
modes either autonomously or controlled by a host processor.
- NORMAL mode: In this mode, the device performs
frequent measurements of system current, cell voltages, internal and thermistor
temperatures, and various other voltages, operates protections as configured, and provides
data and status updates.
- SLEEP mode: In this mode, the DSG FET is enabled, the CHG FET can optionally be disabled, and the device performs measurements, calculations, and data updates in adjustable time intervals. Battery protections are still enabled. Between the measurement intervals, the device is operating in a reduced power stage to minimize total average current consumption.
- DEEPSLEEP mode: In this mode, the CHG, PCHG, DSG, and PDSG FETs are disabled, all battery protections are disabled, and no current or voltage measurements are taken. The REG1 and REG2 LDOs can be kept powered, in order to maintain power to external circuitry, such as a host processor.
- SHUTDOWN mode: The device is completely disabled (including the internal, REG1, and REG2 LDOs), the CHG, PCHG, DSG, and PDSG FETs are all disabled, all battery protections are disabled, and no measurements are taken. This is the lowest power state of the device, which may be used for shipment or long-term storage. All register settings are lost when in SHUTDOWN mode.
The device also includes a CONFIG_UPDATE mode,
which is used for parameter updates. Figure 7-1 shows the transitions between operational modes.