BQ27510-G1 Datasheet, PDF (22/39 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge With Direct Battery Connection

bq27510-G1
SLUS927 – APRIL 2009 ..................................................................................................................................................................................................... www.ti.com
Quit Relax Time specifies the minimum time required for AverageCurrent( ) to remain above the QuitCurrent
threshold before exiting relaxation mode.
Qmax 0 and Qmax 1
Generically called Qmax, these dynamic variables contain the respective maximum chemical capacity of the
active cell profiles, and are determined by comparing states of charge before and after applying the load with the
amount of charge passed. They also correspond to capacity at very low rate of discharge, such as C/20 rate. For
high accuracy, this value is periodically updated by the bq27510 during operation. Based on the battery cell
capacity information, the initial value of chemical capacity should be entered in the Qmax n field for each default
cell profile. The Impedance Track™ algorithm updates these values and maintains them in the associated actual
cell profiles.
Update Status 0, Update Status 1
Bit 0 (0x01) of the Update Status n registers indicates that the bq27510 has learned new Qmax parameters and
is accurate. The remaining bits are reserved. Bits 0 is a status flag that can be set by the bq27510 although a
user can modify it. Bit 0 should never be modified except when creating a golden image file as explained in the
application note Preparing Optimized Default Flash Constants for specific Battery Types (SLUA334.pdf). Bit 0 is
updated as needed by the bq27510.
Avg I Last Run
The bq27510 logs the current averaged from the beginning to the end of each discharge cycle. It stores this
average current from the previous discharge cycle in this register. This register should never need to be
modified. It is only updated by the bq27510 when required.
Avg P Last Run
The bq27510 logs the power averaged from the beginning to the end of each discharge cycle. It stores this
average power from the previous discharge cycle in this register. To get a correct average power reading the
bq27510 continuously multiplies instantaneous current times Voltage( ) to get power. It then logs this data to
derive the average power. This register should never need to be modified. It is only updated by the bq27510
when required.
Delta Voltage
The bq27510 stores the maximum difference of Voltage( ) during short load spikes and normal load, so the
Impedance Track™ algorithm can calculate remaining capacity for pulsed loads. It is not recommended to
change this value.
Default Ra and Ra Tables
These tables contain encoded data and, with the exception of the Default Ra Tables, are automatically updated
during device operation. No user changes should be made except for reading/writing the values from a
pre-learned pack (part of the process for creating golden image files).
DETAILED PIN DESCRIPTIONS
The Operation Configuration Register
Some bq27510 pins are configured via the Operation Configuration data flash register, as indicated in Table 5
3. This register is programmed/read via the methods described in Section Accessing the Data Flash. The register
is located at subclass =64, offset = 0.
High Byte
Low Byte
bit7
RESCAP
–
Table 10. Operation Configuration Bit Definition
bit6
BATG_OVR
IDSELEN
bit5
–
SLEEP
bit4
PFC_CFG1
RMFCC
bit3
PFC_CFG0
BATL_POL
bit2
IWAKE
BATG_POL
bit1
RSNS1
BAT_FN
bit0
RSNS0
TEMPS
22
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