BQ27530-G1 Datasheet, PDF (9/20 Pages) Texas Instruments – Battery Management Unit Impedance Track Fuel Gauge for Use With the bq2416x Charger Controller

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GENERAL DESCRIPTION
bq27530-G1
SLUSAL5 – DECEMBER 2012
The bq27530-G1 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.
The bq27530-G1 can control a bq2416x Charger IC without the intervention from an application system
processor. Using the bq27530-G1 and bq2416x chipset, batteries can be charged with the typical constant-
current, constant voltage (CCCV) profile or charged using a Multi-Level Charging (MLC) algorithm.
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 device control and status registers, as
well as its data flash locations. Commands are sent from system to gauge using the bq27530-G1’s I²C serial
communications engine, and can be executed during application development, pack 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 bq27530-G1’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 key to the bq27530-G1 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 less than 1% error across a wide variety of operating conditions and over the
lifetime of the battery.
The device measures battery 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 device, cell impedance is computed, based on cell current, cell open-circuit voltage
(OCV), and cell voltage under loading conditions.
The device external temperature sensing is optimized with the use of a high accuracy negative temperature
coefficient (NTC) thermistor with R25 = 10.0kΩ ±1%, B25/85 = 3435K ± 1% (such as Semitec NTC 103AT). The
bq27530-G1 can also be configured to use its internal temperature sensor. When an external thermistor is used,
a 18.2k pull up resistor between BI/TOUT and TS pins is also required. The bq27530-G1 uses temperature to
monitor the battery-pack environment, which is used for fuel gauging and cell protection functionality.
To minimize power consumption, the device has different power modes: NORMAL, SLEEP, SLEEP+,
HIBERNATE, and BAT INSERT CHECK. The bq27530-G1 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 bq27530-G1 Technical Reference Manual.
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 © 2012, Texas Instruments Incorporated
Product Folder Links :bq27530-G1
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