Power Modes
37
SLUUBE8 – September 2018
Copyright © 2018, Texas Instruments Incorporated
Functional Description
2.6.1 NORMAL Mode
The fuel gauge is in NORMAL mode when not in any other power mode. During this mode,
Current()
,
Voltage()
, and
Temperature()
measurements are taken, 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 the NORMAL mode, the CEDV algorithm minimizes the
time the fuel gauge remains in this mode.
2.6.2 SLEEP Mode
SLEEP mode is entered automatically if the feature is enabled (
Operation Config A [SLEEP]
bit = 1) and
Current()
is below the programmable level
Sleep Current
. Once entry into SLEEP mode is qualified, but
prior to entering it, the fuel gauge performs a coulomb counter autocalibration to minimize offset.
During SLEEP mode, the fuel gauge periodically takes data measurements and updates its data set.
However, a majority of its time is spent in an idle condition.
The fuel gauge exits the SLEEP mode if any entry condition is broken, specifically when either:
•
Current()
rises above
Sleep Current
.
•
A current in excess of I
WAKE
through R
SENSE
is detected.
2.6.3 SHUTDOWN Mode
In SHUTDOWN mode, REG18 is disabled so internal power and all RAM-based volatile data is lost. The
host can command the gauge to immediately enter SHUTDOWN mode by first unsealing the gauge then
enabling the mode with a
SHUTDOWN_ENABLE
subcommand (0x001B), followed by the
SHUTDOWN
subcommand (0x001C). To exit SHUTDOWN mode, the ALERT pin must be raised from logic low to logic
high for t
ALERT
.
Both
SHUTDOWN_ENABLE
and
SHUTDOWN
are only available while unsealed. Sending
SHUTDOWN_ENABLE
will set
SHUTDOWN_EN
in
CONTROL_STATUS()
. Sending
SHUTDOWN
while
SHUTDOWN_EN
is set will cause the device to immediately shut down. Sealing the gauge will clear
SHUTDOWN_EN
.
Once in SHUTDOWN mode, there are two methods to exit. A power cycle (battery removal and insertion)
is one method. The second method uses the ALERT pin alternative function. Pulling the ALERT pin high
(the time is specified in the data sheet) enables the bq34210-Q1 to exit SHUTDOWN mode and reenter
NORMAL mode.
2.7
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() ENTER_CFG_UPDATE
subcommand to enter
the CONFIG UPDATE mode. Operation in this mode is indicated by the
OperationStatus() [CFGUPDATE]
status bit. In this mode, fuel gauging is suspended while the host uses the data commands to modify the
configuration data blocks. To resume fuel gauging, the host sends a
Control() EXIT_CFG_UPDATE
, or
EXIT_CFG_UPDATE_REINIT
subcommand to exit the CONFIG UPDATE mode, which clears
OperationStatus() [CFGUPDATE]
. After a timeout of approximately 240 seconds (4 minutes), the gauge
automatically exits the CONFIG UPDATE mode if it has not received an
EXIT_CFG_UPDATE
or
EXIT_CFGPUPDATE_REINIT
subcommand from the host.
2.8
Application-Specific Information
2.8.1 Battery Profile Storage and Selection
The fuel gauge supports two predefined CEDV profiles in device ROM that customers can use by sending
the SET_PROFILE_1 or SET_PROFILE_2 command.
In situations where the user wants to input a custom CEDV profile, they must use the system controller to
set the defaults during system initialization.
To send these commands, the gauge must be in CONFIG UPDATE mode.
