Chipset improves battery life and system protection for multi-cell battery packs

Texas Instruments Incorporated (TI) has launched 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 portable designers with 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 (Li-Ion) or lithium-polymer (Li-Poly) 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 (SMBus) interface. The host controller, such as a digital signal processor (DSP), manages remaining battery power to extend system run time.

The bq29312 AFE protection circuit provides protection against overcharge, overload, short-circuit, overvoltage and undervoltage conditions. In overload and short-circuit conditions, the bq29312 turns the FET drive off autonomously. The bq29312 integrates an I2C compatible interface to enable measurement of battery parameters such as cell voltages and pack temperature.

TI also offers the new bq29400 secondary protection IC, which incorporates an accurate independent precision overvoltage detection circuit. 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 overvoltage 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.
The bq2084 comes in a 38-pin TSSOP package and is priced at $4.35; the bq29312 in a 24-pin TSSOP costs $1.20; and the bq29400 an 8-pin TSSOP package is $0.45. All in quantities of 1000.

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