BQ27532-G1 Datasheet, PDF (12/35 Pages) Texas Instruments – Battery Management Unit Impedance Track Fuel Gauge

bq27532-G1
SLUSBU6B – SEPTEMBER 2014 – REVISED JANUARY 2016
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7.4 Device Functional Modes
7.4.1 Power Modes
The fuel gauge has different power modes:
1. BAT INSERT CHECK: The BAT INSERT CHECK mode is a powered-up, but low-power halted, state where
the fuel gauge resides when no battery is inserted into the system.
2. NORMAL: In NORMAL mode, the fuel gauge is fully powered and can execute any allowable task.
3. SLEEP: In SLEEP mode, the fuel gauge turns off the high-frequency oscillator and exists in a reducedpower
state, periodically taking measurements and performing calculations.
4. SLEEP+: In SLEEP+ mode, both low-frequency and high-frequency oscillators are active. Although the
SLEEP+ mode has higher current consumption than the SLEEP mode, it is also a reduced power mode.
5. HIBERNATE: In HIBERNATE mode, the fuel gauge is in a low power state, but can be woken up by
communication or certain I/O activity.
The relationship between these modes is shown in Figure 6.
7.4.2 BAT INSERT CHECK Mode
This mode is a halted-CPU state that occurs when an adapter, or other power source, is present to power the
fuel gauge (and system), yet no battery has been detected. When battery insertion is detected, a series of
initialization activities begin, which include: OCV measurement, setting the Flags() [BAT_DET] bit, and selecting
the appropriate battery profiles.
Some commands, issued by a system processor, can be processed while the fuel gauge is halted in this mode.
The gauge wakes up to process the command, then returns to the halted state awaiting battery insertion.
7.4.3 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, 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.
7.4.4 SLEEP Mode
SLEEP mode is entered automatically if the feature is enabled (Op Config [SLEEP] = 1) and AverageCurrent() is
below the programmable level Sleep Current. Once entry into SLEEP mode has been 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 SLEEP mode if any entry condition is broken, specifically when:
1. AverageCurrent() rises above Sleep Current, or
2. A current in excess of I_WAKE through R_SENSE is detected.
In the event that a battery is removed from the system while a charger is present (and powering the gauge),
Impedance Track™ updates are not necessary. Hence, the fuel gauge enters a state that checks for battery
insertion and does not continue executing the Impedance Track™ algorithm.
7.4.5 SLEEP+ Mode
Compared to the SLEEP mode, SLEEP+ mode has the high-frequency oscillator in operation. The
communication delay could be eliminated. The SLEEP+ mode is entered automatically if the feature is enabled
(CONTROL_STATUS [SNOOZE] = 1) and AverageCurrent() is below the programmable level Sleep Current.
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 SLEEP+ mode if any entry condition is broken, specifically when:
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