STMicroelectronics has unveiled battery fuel-gauge IC STC3115 for battery operated mobile devices to measure energy left in the battery more accurately compared to previous technologies. ST says this devices is already been selected by Samsung for some of its recent smartphones. This device is suggested for portable electronics such as medical devices, where accurate battery level display is important.
To enhance fuel-gauging accuracy, ST has combined several important advances in its latest adaptive fuel-gauge IC, the STC3115. Until now, leading devices have used Coulomb counting to monitor energy entering and leaving the battery, and periodic voltage-mode state-of-charge measurements to adjust the Coulomb counter for accuracy.
The STC3115 uses both Coulomb counting and periodic voltage-mode state-of-charge measurements to accurately determine the amount of energy left in the battery. It uses an adaptive algorithm called OptimGauge to track the state of charge and corrects the battery model.
The STC3115 further enhances accuracy by measuring true initial battery open-circuit voltage and preventing measurement disruptions when connecting the charger or launching an app. The charging inhibitor is a patented feature that significantly improves accuracy. Aging and temperature compensation are built in, and the voltage measurement accuracy is 0.25%.
Additional value-added features of the new IC include a low-power mode that reduces operating current to only 45µA while continuing to monitor the battery, and a 2µA standby mode. An Under-Voltage Lockout (UVLO) filter prevents short-term fluctuations in battery voltage from causing unwanted system resets. In addition, the STC3115 saves bill-of-materials costs by operating directly from the battery voltage without requiring its own voltage regulator.
Other key features of STC3115:
• Industry-standard I2C connection to application processor
• Programmable with different battery profiles at manufacture, for flexibility
• Monitors batteries up to 4.5V
• Monitors multi-cell packs when used with TS941ILT low-power buffer
• Dedicated “battery-present” input simplifies battery replacement
• Dedicated alarm output, activated if battery voltage falls below threshold level
The STC3115 is in full production in a 1.4 x 2.0mm chip-scale package, priced from $.95 in quantities of 1,000 pieces.
For more info visit www.st.com