BQ27505-J4 Datasheet, PDF (28/38 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge

bq27505-J4
SLVSA40 – DECEMBER 2009
www.ti.com
In PFC 1, the /BAT_GD pin is also used to disable battery charging when the bq27505-J4 reads battery
temperatures outside the range defined by [Charge Inhibit Temp Low, Charge Inhibit Temp High]. The
/BAT_GD line is asserted once temperature falls within the range [Charge Inhibit Temp Low + Temp
Hys, Charge Inhibit Temp High – Temp Hys].
5.3.5 Battery Detection Using the BI/TOUT Pin
During power-up or hibernate activities, or any other activity where the bq27505-J4 needs to determine
whether a battery is connected or not, the fuel gauge applies a test for battery presence. First, the
BI/TOUT pin is put into high-Z status. The weak 1.8MΩ pull-up resistor will keep the pin high while no
battery is present. When a battery is inserted (or is already inserted) into the system device, the BI/TOUT
pin will be pulled low. This state is detected by the fuel gauge, which polls this pin every second when the
gauge has power. A battery-disconnected status is assumed when the bq27505-J4 reads a thermistor
voltage that is near 2.5V.
5.3.6 SOC_INT pin
The SOC_INT pin generates a pulse with different pulse width under various conditions. Some features
needs to be enabled by setting the Operation Config.
Table 5-5. Operation Configuratin B BIt Definition
Enable Condition
SOC_Delta
Point
SOC_Delta ≠ 0
SOC1 Set Always
SOC1 Clear Always
SysDown Set Always
SysDown
Clear
Always
State Change _{SOC_Delta ≠ 0}
Battery
Removal
INT_BREM bit is set in
OpConfig
OCV
Command
After Initialization
OCV
Command
INT_FOCV bit is set in
OpConfig
Data Flash
Write
Factory
Restore
After Initialization AND
DFWrIndWaitTime ≠ 0
Always
Pulse Width
1 ms
1 ms
1 ms
1 ms
1 ms
Comment
During charge, when the SOC is greater than (≥) the points, 100% + n
× SOC_Delta and 100%;
During discharge, when the SOC reaches (<) the points 100% + n ×
SOC_Delta and 0%;
where n is an integer starting from 0 to the number generating SOC no
less than 100%
When RSOC reached the SOC1 Set or Clear threshold set in the Data
Flash
When the Battery Voltage reached the SysDown Set or Clear threshold
set in the Data Flash
1 ms
When there is a state change including charging, discharging and
relaxation.
1ms
—
Same as the OCV
SOC_INT pulses for the OCV command after the initialization.
command execution time
period
Same as the OCV
This command is to generate the SOC_INT pulse during the
command execution time initialization.
period
Programmmable time
pluse flash erase and
write time
SOC_INT is used to indicate the data flash update. The gauge will wait
DFWrIndWaitTime times 5μs after the SOC_INT signal to start the data
flash update. This function is disabled if DFWrIndWaitTime is set to 0.
Time for restore function Asserted while dataflash learned Ra tables and Qmax are overwritten
to complete
with defaults.
5.4 TEMPERATURE MEASUREMENT
The bq27505-J4 measures battery temperature via its TS input, in order to supply battery temperature
status information to the fuel gauging algorithm and charger-control sections of the gauge. Alternatively, it
can also measure internal temperature via its on-chip temperature sensor, but only if the [TEMPS] bit of
Operation Configuration register is cleared.
28
FUNCTIONAL DESCRIPTION
Submit Documentation Feedback
Copyright © 2009, Texas Instruments Incorporated