BQ27510-G2 Datasheet, PDF (7/38 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge With Direct Battery Connection

bq27510-G2
www.ti.com
SLUS948 – AUGUST 2010
GENERAL DESCRIPTION
The bq27510-G2 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
state-of-charge (SOC), time-to-empty (TTE) and time-to-full (TTF).
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( ), are used to read and write information contained within the bq27510-G2 control and status
registers, as well as its data flash locations. Commands are sent from system to gauge using the bq27510-G2’s
I²C serial communications engine, and can be executed during application development, pack manufacture, or
end-equipment operation.
Cell information is stored in the bq27510-G2 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 bq27510-G2’s 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 bq27510-G2 provides 64 bytes of user-programmable data flash memory, partitioned into two 32-byte
blocks: Manufacturer Info Block A and Manufacturer Info Block B. This data space is accessed through a
data flash interface. For specifics on accessing the data flash, see section Manufacturer Information Blocks.
The key to the bq27510-G2’s high-accuracy gas gauging prediction is Texas Instrument’s proprietary Impedance
Track™ algorithm. This algorithm uses cell measurements, characteristics, and properties to create
state-of-charge predictions that can achieve high accuracy across a wide variety of operating conditions and over
the lifetime of the battery.
The bq27510-G2 measures charge/discharge activity by monitoring the voltage across a small-value series
sense resistor (5 mΩ to 20 mΩ typ.) located between the system’s Vss and the battery’s PACK– terminal. When
a cell is attached to the bq27510-G2, cell impedance is computed, based on cell current, cell open-circuit voltage
(OCV), and cell voltage under loading conditions.
The bq27510-G2 can use an NTC thermistor (default is Semitec 103AT) for temperature measurement, or can
also be configured to use its internal temperature sensor. The bq27510-G2 uses temperature to monitor the
battery-pack environment, which is used for fuel gauging and cell protection functionality.
To minimize power consumption, the bq27510-G2 has several power modes: NORMAL, SLEEP, HIBERNATE,
and BAT INSERT CHECK. The bq27510-G2 passes automatically between these modes, depending upon the
occurrence of specific events, though a system processor can initiate some of these modes directly. More details
can be found in Section Power Modes.
NOTE
FORMATTING CONVENTIONS IN THIS DOCUMENT:
Commands: italics with parentheses and no breaking spaces, e.g.
RemainingCapacity( ).
Data Flash: italics, bold, and breaking spaces, e.g. Design Capacity.
Register bits and flags: brackets and italics, e.g. [TDA]
Data flash bits: brackets, italics and bold, e.g: [LED1]
Modes and states: ALL CAPITALS, e.g. UNSEALED mode.
Copyright © 2010, Texas Instruments Incorporated
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