Battery fuel gauge for JEITA profile

Paul Boughton

Texas Instruments has developed a family of battery fuel gauge integrated circuits (ICs) with enhanced charging, including the Japan Electronics and Information Technology Association (JEITA) profile.

The new battery fuel gauges feature TI’s Impedance Track technology and provide the highest degree of capacity measurement for two- to four-cell battery packs used in next-generation notebooks and netbooks, portable industrial and medical equipment.

The bq20z4x and bq20z6x devices are pin-compatible with TI’s popular bq20z7x and bq20z9x series of products with Impedance Track. The bq20z45 and bq20z65 are single-package ICs with integrated battery protection, while the bq20z40 and bq20z60 are dual-package ICs requiring a companion bq29330 analogue front end device. The bq20z6x family supports LED functionality.

The devices support all the JEITA parameters and are configurable according to temperature, charging currents and charging voltages with support for charging voltage and cell over-voltage threshold varies with temperature. The charging current can also be adjusted based on battery voltage and temperature.

Additional features and benefits include accurate runtime prediction for batteries with extremely flat voltage profiles, cell voltage-based taper termination improves charge termination accuracy, enhanced cell imbalance detection in charge mode, two independent thermistor controls enable simultaneous monitoring of battery temperature and MOSFETs and access to lifetime battery data to simplify diagnostics.

The bq20z45 and bq20z65 single-chip fuel gauges come in a 38-pin TSSOP with a suggested resale price of $4.40 in 1,000-unit quantities. The bq20z40 and bq20z60 come in a 20-pin TSSOP and have a suggested resale price of $3.40 in 1,000-unit quantities. The bq29330 is available in a 30-pin TSSOP with a price of $1.00 in 1,000-unit quantities.

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