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Operating Modes
2.4
Operating Modes
The fuel gauge has different operating modes: POR, INITIALIZATION, NORMAL, CONFIG UPDATE,
SLEEP, and HIBERNATE. Upon powering up from OFF or SHUTDOWN, a power-on reset (POR) occurs
and the fuel gauge begins INITIALIZATION. In NORMAL mode, the fuel gauge is fully powered and can
execute any allowable task. Configuration data in RAM can be updated by the host using the CONFIG
UPDATE mode. In SLEEP mode, the fuel gauge turns off the high-frequency oscillator clock to enter a
reduced-power state, periodically taking measurements and performing calculations. In HIBERNATE
mode, the fuel gauge is in a very-low-power state, but can be woken up by communication.
2.4.1 SHUTDOWN Mode
In SHUTDOWN mode, the LDO output is disabled so internal power and all RAM-based volatile data are
lost. The host can command the gauge to immediately enter SHUTDOWN mode by first enabling the
mode with a
SHUTDOWN_ENABLE
subcommand (
) followed by the
SHUTDOWN
subcommand (
). To exit SHUTDOWN mode, the GPOUT pin must be raised from logic low
to logic high for at least 200 µs.
2.4.2 POR and INITIALIZATION Modes
Upon POR, the fuel gauge copies ROM-based configuration defaults to RAM and begins INITIALIZATION
mode where essential data is initialized. It will remain in INITIALIZATION mode as a halted-CPU state
when an adapter or other power source is present to power the fuel gauge (and system), yet no battery
has been detected. The occurrence of POR or a
Control() RESET
subcommand will set the
Flags()
[ITPOR]
status bit to indicate that RAM has returned to ROM default data.
When battery insertion is detected, a series of initialization activities begin including an OCV
measurement. In addition, the
CONTROL_STATUS [QMAX_UP]
and
[RES_UP]
bits are cleared to allow
unfiltered learning of Qmax and impedance. Completion of INITIALIZATION mode is indicated by the
CONTROL_STATUS [INITCOMP]
bit.
2.4.3 CONFIG UPDATE Mode
If the application requires different configuration data for the fuel gauge, the system processor can update
RAM-based Data Memory parameters using the
Control() SET_CFGUPDATE
subcommand to enter the
CONFIG UPDATE mode. Operation in this mode is indicated by the
Flags() [CFGUPMODE]
status bit. In
this mode, fuel gauging is suspended while the host uses the extended data commands to modify the
configuration data blocks.
To resume fuel gauging, the host sends a
Control() SOFT_RESET
,
EXIT_CFGUPMODE
, or
EXIT_RESIM
subcommand to exit the CONFIG UPDATE mode which clears both
Flags() [ITPOR]
and
[CFGUPMODE]
bits. After a timeout of approximately 240 seconds (4 minutes), the gauge will automatically exit the
CONFIG UPDATE mode if it has not received a
SOFT_RESET
,
EXIT_CFGUPMODE
, or
EXIT_RESIM
subcommand from the host.
2.4.4 NORMAL Mode
The fuel gauge is in NORMAL mode when not in any other power mode. During this mode,
AverageCurrent()
,
Voltage(),
and
Temperature()
measurements are taken once per second, and the
interface data set is updated. Decisions to change states are also made. This mode is exited by activating
a different power mode.
Because the gauge consumes the most power in NORMAL mode, the Impedance Track™ algorithm
minimizes the time the fuel gauge remains in this mode.
9
SLUUAC9A – December 2013 – Revised May 2015
Functional Description
Copyright © 2013–2015, Texas Instruments Incorporated