TI Announces New Gas Gauge/Protection ChipsetAugust 12, 2003 by Jeff Shepard
Texas Instruments Inc. (TI, Dallas, TX) announced a new chipset featuring three advanced battery management integrated circuits (ICs) for two-, three- or four-series cell battery packs used in portable medical appliances, notebook computers, test and measurement, and industrial equipment. TI's new battery fuel gauge, protection analog front-end (AFE) chip and secondary protection device provide reduced quiescent current, increased efficiency and protection, while maintaining lower component count and cost.
The bq2084 Smart Battery Specification (SBS), version 1.1-compliant, gas gauge maintains an accurate record of available charge in lithium-ion or lithium-polymer batteries, and is a key piece of the battery management chipset. The device monitors capacity and other critical parameters of the battery pack, and reports the information to the system host controller over a system management bus interface. The host controller manages remaining battery power to extend system run time.
The gas gauge is offered with the new bq29312 AFE protection circuit, which provides safety protection for over-charge, overload, short-circuit, over-voltage and under-voltage conditions with the battery management host processor. In overload and short-circuit conditions, the bq29312 turns the FET drive off autonomously and dependant of the internal configuration setting.
The new bq29400 secondary protection IC, which incorporates an accurate, independent, precision over-voltage detection circuit, is also offered. With the secondary voltage protector, each battery cell in a multi-cell battery pack is compared to an internal reference voltage. If one cell gets into an over-voltage condition, the bq29400 will wait over a programmed period of time and set an output to drive an external FET, which can be used to burn a chemical fuse to further protect the system.
All three components of the chipset are available now. The bq2084 comes in a 38-pin, TSSOP package; the bq29312 in a 24-pin, TSSOP package; and the bq29400 comes in an 8-pin, TSSOP package. Suggested resale pricing in 1,000-piece quantities include $4.35 each for the bq2084, $1.20 each for the bq29312 and $0.45 each for the bq29400. A combined evaluation module is available for all three devices.