Two integrated Li-Ion fuel-gauge and -protection ICs from Texas Instruments feature the company's Impedance Track technology, which provides runtime prediction for batteries with flat voltage profiles. The bq20z4x and bq20z6x battery fuel-gauge ICs feature enhanced charging, including the JEITA (Japan Electronics and Information Technology Association) profile. They are claimed to provide the highest degree of capacity measurement for two- to four-cell battery packs used in next-generation notebooks, netbooks, as well as portable industrial and medical equipment. Both devices are pin-compatible with the company's bq20z7x and bq20z9x products, also with Impedance Track. Within the device families, 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. All devices are configurable to JEITA parameters—that is, according to temperature, charging currents and charging voltages. The devices have charging voltage and cell over-voltage thresholds that vary with temperature. Charging current can be adjusted based on battery voltage and temperature. The devices use cell voltage-based taper termination to improve-charge termination accuracy, says the company. The devices also provide enhanced cell-imbalance detection in charge mode. There are two independent thermistor controls to enable simultaneous monitoring of battery temperature and MOSFETs. The bq20z45 and bq20z65 single-chip fuel gauges come in a 38-pin TSSOP. The bq20z40 and bq20z60 come in a 20-pin TSSOP. The bq29330 is available in a 30-pin TSSOP.
