TI Debuts bq2081/bq29311 Battery ChipsetSeptember 25, 2001 by Jeff Shepard
Texas Instruments Inc. (TI, Dallas, TX) introduced its first chipset for capacity monitoring and safety protection in lithium-ion or lithium-polymer battery packs.
Designed for battery pack integration, the chipset provides all the necessary functionality required for accurate battery capacity monitoring and primary safety control and voltage balancing of the lithium-ion cells. The chipset is ideal for use in notebook computers, hand-held terminals, medical and test equipment, and other portable equipment powered by three or four series lithium-ion or lithium-polymer battery packs.
The battery management chipset consists of the bq2081 smart battery system (SBS version 1.1) gas gauge IC and the bq29311 lithium-ion protector IC. As a chipset, the bq2081/bq29311 solution simplifies the design and reduces the number of components required for a lithium-ion SBS-compatible battery fuel gauge and protection circuit by as much as 40 percent compared to previous generations or competitive solutions. As a result, the bq2081/bq29311 circuit can fit in less than 1sqin of PCB space.
The bq2081 is the first in a series of battery capacity monitoring ICs. The bq2081 employs a continuous self-calibrating integrated ADC. The converter has a resolution better than 3nVh with a calibrated measurement offset error of 1mµV (typical). In addition, the bq29311 serves as the lithium-ion cell protector and analog front end to the bq2081. Accepting an input voltage of up to 25V, the bq29311 runs directly off the battery stack voltage and provides a regulated 3.3V to the bq2081, sources LED current for capacity indication and provides bias current for the temperature sense network.
Additional features include an SBS version 1.1 compatible data set and communication protocol with packet error checking, as well as complete lithium-ion protection, including programmable thresholds for over-voltage/under-voltage, over-current (charge and discharge), short-circuit, over-temperature, and cell balancing.
Samples of the bq2081 and bq29311 will be available in November 2001, with volume production planned for December 2001. The bq2081 is packaged in a 38-pin TSSOP (DBT) while the bq29311 is supplied in a 24-pin TSSOP (PW). Suggested resale pricing in quantities of 1,000 is $4.05 for the bq2081 and $1.20 for the bq29311.