BQ27505 Datasheet, PDF (29/42 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge

Not Recommended for New Designs
bq27505
www.ti.com
SLUS884 – FEBRUARY 2009
In PFC 1, the BAT_GD pin is also used to disable battery charging when the bq27505 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 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 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. SOC_INT Pulse Condition and Width
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
Fail
When CHG_INH is set
OCV
Command
After Initialization
OCV
Command
INT_FOCV bit is set in
OpConfig
Pulse Width
1 ms
1 ms
1 ms
1 ms
1 ms
Comment
During charge, when the SOC reaches (≥) the points, 1% + n ×
SOC_Delta and 100%;
During discharge, when the SOC is less than (<) the points 1% + n ×
SOC_Delta and 0%;
where n is an integer starting from 0 and the number generating SOC
no greater than 100%
When RSOC reached the SOC1 Set or Clear threshold set in the Data
Flash and BL_INT bit in Operation Configuration B is set.
When the Battery Voltage reached the SysDown Set or Clear threshold
set in the Data Flash
1 ms
1ms
1ms
When there is a state change including charging, discharging and
relaxation -
The OCV Command is failed when CHG_INT is set. The OCV_FAIL bit
is also set.
Same as the OCV
command execution
time period
Same as the OCV
command execution
time period
SOC_INT pulses for the OCV command after the initialization
This command is to generate the SOC_INT pulse during the
initialization
Copyright © 2009, Texas Instruments Incorporated
Submit Documentation Feedback
Product Folder Link(s): bq27505
FUNCTIONAL DESCRIPTION
29