Battery Management Chips Suit Li-Ion Packs

Jan 17, 2007 12:51 PM

Texas Instruments’ (TI) bq20z90 Impedance Track battery gas gauge chipset, which integrates battery authentication technology, is designed to work with TI’s newest analog front end (AFE) protection IC, the bq29330. The Impedance Track “gas gauge” chipset is designed to improve battery performance and protect multi-cell, lithium-based battery packs. These batteries are used in notebooks and other systems.

Requiring a third fewer components than its predecessor, the 99% accurate chipset closely monitors battery capacity, impedance, cell balance, open-circuit voltage and other critical parameters of a 7.2-V, 10.8-V or 14.4-V battery pack. It then reports the information to the system host controller over a serial-communication bus.

The bq20z90 drives a three-, four- or five-segment LED display for remaining capacity indication. For those designs that do not require the display indicator, TI also introduced its bq20z70 gas gauge chipset without the LED display driver.

The bq20z90 integrates SHA-1, 128-bit decryption functionality, which easily identifies potentially unsafe batteries not approved by original equipment manufacturers for use in their devices. In addition, TI introduced a bq26100 protection device for those designers who prefer a discrete implementation of the SHA-1 protection feature.

The bq20z90 and bq20z70 gas gauge chipsets are available in volume production. The bq20z90 is packaged in a 30-pin thin-shrink small outline package (TSSOP), the smaller bq29z70 in a 20-pin TSSOP. Suggested resale pricing in 1000 piece quantities is $3.30 for the bq20z90 and $2.90 for the bq20z70. Also, TI’s bqMTester smart battery development board simplifies production of battery modules at a fraction of the cost and is available online.