TI battery monitor calculates capacity, run-time

Designed for single-cell Li-ion and Li-polymer battery packs, the bgJunior (part number: bg270x0) battery fuel gauge from Texas Instruments Inc. is capable of calculating the remaining battery capacity and system run-time within a single chip.

This capability "simplifies the design of a cost-effective accurate battery fuel gauge in single cell applications by offering a solution that performs all the necessary intelligent calculations on-chip, significantly reducing the amount of calculations performed by the host-side microcontroller," said Peter Fundaro, worldwide marketing manager for TI's battery management products.

Unlike a standard battery monitor, the bqJunior incorporates an on-board processor to calculate the remaining battery capacity and system run-time (time-to-empty). The device measures the battery's charge and discharge currents to within one percent error using an integrated low-offset voltage-to-frequency converter.

A separate ADC is used to measure battery voltage and temperature. Using the measurement inputs, the bqJunior runs an algorithm to calculate remaining battery capacity and system run-time. The device compensates remaining battery capacity and run-times for battery discharge rate and temperature variations.

The fuel gauge also measures available power, average current, temperature, voltage, and time to empty and full charge. The bqJunior includes a single wire communications port (HDQ protocol) to communicate the data set to the system host controller.

Other features include internal time-base for reduced component count, on-chip configuration EEPROM for application specific parameters, and programmable I/O port.

The device operates directly from a single Li-ion cell and draws <100?A. It features three low power standby modes to minimize battery consumption during periods of system inactivity.

It is packaged in an 8-pin TSSOP or QFN (3-by-4mm) package and is priced at $2.55 per unit in quantities of 1,000.