This device supports 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 temperature, and various other
voltages, operates protections as configured, and provides data and status
updates. Battery protections are enabled, and the FET drivers are typically
enabled (in the absence of any protection fault).
- SLEEP mode: In this mode, the device performs
measurements, calculations, and data updates in adjustable time intervals.
Between the measurement intervals, the device is operating in a reduced power
state to minimize total average current consumption. Battery protections are
still enabled (with modified timing for those using the ADC), and the DSG FET
driver (and the CHG FET driver depending on setting) is typically enabled (in
the absence of any protection fault).
- DEEPSLEEP mode: In this mode, the FET drivers are
disabled, all battery protections are disabled, and no current, voltage, or
temperature measurements are taken. The REGOUT LDO can be optionally kept
powered, in order to maintain power to external circuitry, such as a host
processor. The programmable timer can optionally be used to wake the device and
REGOUT LDO after a programmed time interval.
- SHUTDOWN mode: The device is completely disabled (including the internal 1.8 V and REGOUT LDOs), the CHG and DSG FETs are both disabled, all battery protections are disabled, and no measurements are taken.
This is the lowest power state of the device, which can be used for shipment or long-term storage. All register settings (other than settings programmed into OTP by TI) are lost when in SHUTDOWN mode.
The device also includes a CONFIG_UPDATE mode,
which is used for parameter updates. Transitioning between operational modes is
shown in BQ76905 Operational Power Modes.