Texas Instruments has developed what it claims is the industry’s first fully integrated battery fuel gauge IC for single-cell lithium-ion (Li-Ion) and lithium-polymer (Li-Polymer) battery packs.
Unlike a standard battery monitor, the bq270x0, or bqJunior, battery fuel gauge 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 1% error using an integrated low-offset voltage-to-frequency converter. A separate analog-to-digital converter on the integrated circuit is used to measure battery voltage and temperature. Using the measurement inputs, the bqJunior runs a proven algorithm to accurately calculate remaining battery capacity and system run-time.
bqJunior compensates remaining battery capacity and run-times for battery discharge rate and temperature variations. Because the device performs the algorithm and data set calculations, there is no need to develop and incorporate code to implement those tasks in the host system processor, which helps reduce development time and total implementation cost.
The host system processor simply reads the data set in the bqJunior to retrieve remaining battery capacity, run-time and other critical information that is fundamental to comprehensive battery and power management, including: 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, such as TI’s OMAP1510 and OMAP5910 application processors.
The fuel gauge operates directly from a single Li-Ion cell and operates at less than 100uA. It features three low power standby modes to minimise battery consumption during periods of system inactivity, on-chip configuration EEPROM for application specific parameters and a programmable input/output port.
Samples of the bqJunior battery fuel gauge are currently available to select customers. Volume production is scheduled for the second quarter.
The bqJunior device is packaged in an 8-pin TSSOP or QFN (3 mm x 4 mm) package. The part is priced at $2.55 per unit in quantities of 1,000.