BQ27510-G3 Datasheet, PDF (7/20 Pages) Texas Instruments – System-Side Impedance Track Fuel Gauge With Direct Battery Connection

bq27510-G3
www.ti.com
SLUSAT1 – MARCH 2013
GENERAL DESCRIPTION
The bq27510-G3 fuel gauge accurately predicts the battery capacity and other operational characteristics of a
single Li-based rechargeable cell. It can be interrogated by a system processor to provide cell information, such
as time-to-empty (TTE) and state-of-charge (SOC) as well as SOC interrupt signal to the host.
Information is accessed through a series of commands, called Standard Commands. Further capabilities are
provided by the additional Extended Commands set. Both sets of commands, indicated by the general format
Command( ), read and write information contained within the device control and status registers, as well as its
data flash locations. Commands are sent from system to gauge using the I²C serial communications engine, and
can be executed during application development, system manufacture, or end-equipment operation.
Cell information is stored in the device in non-volatile flash memory. Many of these data flash locations are
accessible during application development. They cannot, generally, be accessed directly during end-equipment
operation. Access to these locations is achieved by either use of the fuel gauge companion evaluation software,
through individual commands, or through a sequence of data-flash-access commands. To access a desired data
flash location, the correct data flash subclass and offset must be known.
The key to the fuel gauge high-accuracy gas gauging prediction is Texas Instruments proprietary Impedance
Track™ algorithm. This algorithm uses cell measurements, characteristics, and properties to create state-of-
charge predictions that can achieve less than 1% error across a wide variety of operating conditions and over the
lifetime of the battery.
The fuel gauge measures charge and discharge activity by monitoring the voltage across a small-value series
sense resistor (5 mΩ to 20 mΩ, typical) located between the system V_SS and the battery PACK– terminal. When
a cell is attached to the device, cell impedance is learned, based on cell current, cell open-circuit voltage (OCV),
and cell voltage under loading conditions.
The external temperature sensing is optimized with the use of a high-accuracy negative temperature coefficient
(NTC) thermistor with R25 = 10.0 kΩ ±1%. B25/85 = 3435 kΩ ± 1% (such as Semitec NTC 103AT). Alternatively,
the fuel gauge can also be configured to use its internal temperature sensor or receive temperature data from the
host processor. When an external thermistor is used, a 18.2-kΩ pull-up resistor between BI/TOUT and TS pins is
also required. The fuel gauge uses temperature to monitor the battery-pack environment, which is used for fuel
gauging and cell protection functionality.
To minimize power consumption, the fuel gauge has several power modes: NORMAL, SLEEP, HIBERNATE, and
BAT INSERT CHECK. The fuel gauge passes automatically between these modes, depending upon the
occurrence of specific events, though a system processor can initiate some of these modes directly.
For complete operational details, refer to bq27510-G3 Technical Reference Manual.
Formatting conventions used in this document:
Information Type
Commands
NVM Data
Register bits and flags
NVM Data bits
Modes and states
Formatting Convention
Italics with parentheses and no breaking spaces
Italics, bold, and breaking spaces
Brackets and italics
Brackets, italics, and bold
ALL CAPITALS
Example
RemainingCapacity( ) command
Design Capacity data
[TDA] bit
[LED1] bit
UNSEALED mode
Copyright © 2013, Texas Instruments Incorporated
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