New Battery "Fuel Gauge" IC from STMicroelectronics Gives Reliable Runtimes for Mobile Users

Thu Feb 14, 2013 9:00am EST

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Innovative state-of-charge calculator maintains accurate fuel gauging with battery age and usage

Geneva, February 14, 2013 - STMicroelectronics (NYSE: STM), a global semiconductor leader
supplying customers across the spectrum of electronics applications and a leading manufacturer of
standard ICs, has unveiled its latest battery fuel-gauging device featuring patented innovations
that improve long-term accuracy. This tiny chip, the STC3115 , can be used in high-volume handheld
electronics, and has already been selected by Samsung for some of its recent smartphones. Battery
charge indicators - or fuel gauges - have become essential for managing devices such as
smartphones, laptops or digital cameras. Accurate "time-remaining" predictions enhance the user's
experience, and can be critical in certain types of portable electronics such as medical devices.
Even so, many of today's fuel-gauging electronics are susceptible to errors caused by battery
aging, reduced charging efficiency, leakage, variations in system power demand, and temperature

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 sets of
measurements continuously, with OptimGauge(TM), an adaptive algorithm that tracks 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 0.45µA 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.

Key features of STC3115:

*The OptimGauge algorithm, which adjusts the battery charge/discharge model over the battery's
*Industry-standard I2C connection to application processor
*Programmable with different battery profiles at manufacture, for flexibility
*Monitors batteries up to 4.5V
*TS941ILTMonitors multi-cell packs when used with  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. If your company has
high-volume requirements please contact your local ST sales office.

About STMicroelectronics
ST is a global leader in the semiconductor market serving customers across the spectrum of sense
and power and automotive products and embedded processing solutions. From energy management and
savings to trust and data security, from healthcare and wellness to smart consumer devices, in the
home, car and office, at work and at play, ST is found everywhere microelectronics make a positive
and innovative contribution to people's life. By getting more from technology to get more from
life, ST stands for life.augmented.

In 2012, the Company's net revenues were $8.49 billion. Further information on ST can be found at .

For Press Information Contact:
Michael Markowitz
Director Technical Media Relations
+1 781 591 0354 
Battery Fuel Gauge from ST 
Battery Fuel Gauge from ST_IMAGE 


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