BQ27510-G2 Datasheet, PDF (27/38 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge With Direct Battery Connection

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bq27510-G2
SLUS948 – AUGUST 2010
POR
Exit From HIBERNATE
Battery Removed
Exit From HIBERNATE
Communication Activity
AND Comm address is for bq27510
bq27510 clears Control Status
[HIBERNATE ] = 0
Recommend Host also set Control
Status [HIBERNATE] = 0
BAT INSERT CHECK
Check for battery insertion
from HALT state.
No gauging
Flags [BAT _DET] = 0
Entry to NORMAL
Flags [BAT _DET] = 1
Exit From NORMAL
Flags [BAT _DET] = 0
NORMAL
Fuel gauging and data
updated every 1s
Exit From SLEEP
Flags [BAT_DET] = 0
HIBERNATE
Disable all bq27510
subcircuits except GPIO.
Negate BAT_GD
Wakeup From HIBERNATE
Communication Activity
AND
Comm address is NOT for bq27510
Entry to SLEEP+
Operation Configuration[SLEEP] = 1
AND
Control Status[SNOOZE] = 1
AND
| AverageCurrent( ) | ≤ Sleep Current
Entry to SLEEP
Operation Configuration[SLEEP] = 1
AND
| AverageCurrent( ) | ≤ Sleep Current
AND
Control Status[SNOOZE] = 0
Exit From WAIT_HIBERNATE
Cell relaxed
AND
| AverageCurrent() | < Hibernate
Current
OR
Cell relaxed
AND
VCELL < Hibernate Voltage
WAIT_HIBERNATE
Fuel gauging and data
updated every 20 seconds
BAT_GD unchanged
System Shutdown
Entry to SLEEP+
Control Status[SNOOZE] = 0
Exit From WAIT _HIBERNATE
Host must set Control Status
[HIBERNATE ] = 0
AND
VCELL > Hibernate Voltage
Exit From SLEEP
| AverageCurrent( ) | > Sleep Current
OR
Exit From SLEEP+ ^{Current is Detected above IWAKE}
Any communication to the gauge
OR
| AverageCurrent( ) | > Sleep Current
OR
Current is Detected above IWAKE
SLEEP+
Fuel gauging and data
updated every 20 seconds
Both LFO and HFO are ON
Entry to SLEEP+
Control Status[SNOOZE] = 1
SLEEP
Fuel gauging and data
updated every 20 seconds
(LFO ON and HFO OFF)
Exit From SLEEP
(Host has set Control Status
[HIBERNATE] = 1
OR
V_CELL < Hibernate Voltage
System Sleep
Figure 3. Power Mode Diagram
HIBERNATE Mode
HIBERNATE mode could be used when the system equipment needs to enter a very low-power state, and
minimal gauge power consumption is required. This mode is ideal when a system equipment is set to its own
HIBERNATE, SHUTDOWN, or OFF modes.
Before the fuel gauge can enter HIBERNATE mode, the system must set the [HIBERNATE] bit of the
CONTROL_STATUS register. The gauge waits to enter HIBERNATE mode until it has taken a valid OCV
measurement and the magnitude of the average cell current has fallen below Hibernate Current. The gauge can
also enter HIBERNATE mode if the cell voltage falls below Hibernate Voltage. The gauge will remain in
HIBERNATE mode until the system issues a direct I²C command to the gauge. I²C Communication that is not
directed to the gauge will not wake the gauge (or at least for very long).
It is important that BAT_LOW/BAT_GD be set to disable status (no battery charging/discharging). This prevents
a charger application from inadvertently charging the battery before an OCV reading can be taken. It is the
system’s responsibility to wake the bq27510-G2 after it has gone into HIBERNATE mode. After waking, the
gauge can proceed with the initialization of the battery information (OCV, profile selection, etc.)
It is suggested to keep the system in the SLEEP mode instead of HIBERNATE mode when a charger is
attached. The reason is that charger removal will not wake up the battery from HIBERNATE mode.
Copyright © 2010, Texas Instruments Incorporated
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