Gas-Gauge IC Takes A Ride On Power-Assisted Vehicles

Critical battery parameters in large-capacity packs used in high discharge-rate applications, such as power-assisted bicycles and other electric vehicles, are monitored by the bq2013H gas-gauge IC. The IC is designed for integration within NiCd, NiMH or lead-acid packs and accurately tracks the pack's voltage, temperature and remaining capacity.Battery data is transferred to a host system controller using a single-wire, bi-directional serial communication port. The chip outputs battery information in response to external commands sent by means of the serial link. Or, the IC can directly light five LEDs to indicate remaining battery power to the end user at the touch of a button.The chip integrates a highly sensitive voltage-to-frequency converter for current measurement, an A/D converter for battery temperature and voltage measurement, and a temperature-stable time base. The host of features offered by the IC makes it suitable for power-assisted vehicle applications. It accurately measures a wide dynamic current range of 100 mA to 100A. It accommodates large pack capacities of up to 2 Ah. In addition, automatic adjustments are made for pack self-discharge, circuit offset and battery charge efficiencies.Operation can be directly from four nickel cells or three lead-acid cells. The IC's voltage reference output can be used with an external transistor to build a simple, low-cost regulator to provide V_CC from a greater number of cells. Samples of the 16-pin, 150-mil SOIC are available now.