Texas Instruments has announced a new battery management system with remarkably low quiescent current, 700-nA with the buck converter, operating at 1.8V. With this, TI claims that it has created the industry’s lowest quiescent current. With its programmable range of charging options, it is appropriate for wearables developers who want a battery that is both small in size and carries a high-capacity charge.
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The bq25120 battery management solution is always on, leveraging power path technology to maintain the 1.8V operation. A host microprocessor can also continue running during recharging, because it does not extract “empty energy.” A standby mode with quiescent current of 50-nA is also available to help designers achieve the longest possible battery shelf life. The batteries also include an accurate charge termination feature, which maximizes the energy delivered to the battery before completing the charging cycle, enabling it to draw a more robust charge.
An integrated battery voltage monitor indicates the state of charge, as well as a buck converter (which provides power to the MCU) and pushbutton control features. A configurable load switch/LDO output enables the system to shut off rarely-used functions in order to minimize battery drain.
Because the battery is small, with a 2.5-mm by 2.5-mm WCSP package, it is appropriate for integrating into wearables. More robust battery management can be enabled by including the CC2640 wireless MCU, which TI claims is the industry’s smallest QFN package solution with integrated Flash for Bluetooth Smart.
The bq25120 was built with designers in mind, and gives people the flexibility to set their own parameters. Using the I2C programming interface, designers can set the battery charger voltage, current, termination threshold, input current limit, load switch control, flexible timer and reset options, and more on their own.
The bq25120 charger is currently available from Texas Instruments at $1.60 in 1,000 unit quantities. An evaluation model optimized to evaluating the bq25120’s features and performance is also available at $99.
