Texas Instruments' bq28550 battery gas gauge provides current and voltage protection, and secure, SHA-1/HMAC authentication for single-cell Li-Ion battery packs. Designed for battery-pack integration, the bq28550 requires host microcontroller firmware support for implementation. A system processor communicates with the bq28550 using one of the serial interface configurations to obtain remaining battery capacity, system run-time predictions, and other critical battery information. The bq28550 uses an accurate gas-gauging algorithm to report the status of the cell. The gauge provides information such as state-of-charge (%), run-time to empty (min.), charge-time to full (min.), battery voltage (V), and pack temperature (°C).