700-nA Quiescent Current Enables Always-On Wearable Designs

Overview

TI introduced a compact, low-power battery management solution for wearable and IoT products. The bq25120 integrates a linear charger, configurable LDO, load switch, buck converter, push-button control, and battery-voltage monitor. It supports batteries from 3.6 V to 4.65 V and fast-charge currents from 5 mA to 300 mA, enabling wearable and industrial IoT devices to remain always-on without excessive battery drain.

Features

700 nA quiescent current: The bq25120 uses power-path management and a low-Iq buck converter to maintain a 1.8 V system rail with quiescent current as low as 700 nA. Host microprocessors, such as TI host processors or Bluetooth radios like TI SimpleLink CC2640 Bluetooth low energy MCU, can continue operating during charging without drawing idle energy. The device also provides a 50 nA standby-mode static current for extended battery shelf life.
High integration: Configurable load switch and LDO outputs allow the system to disable infrequently used functions, such as radios and displays, to reduce battery consumption. The solution also includes an integrated battery-voltage monitor for charge indicators, a buck converter, and push-button control functions.
Compact package: The device is offered in a 2.5 mm x 2.5 mm WCSP package, minimizing board area for integration into small wearable form factors. For more integrated designs, the CC2640 wireless MCU is available in a small QFN package with embedded Bluetooth low energy flash.
Precise charge termination down to 500 uA: Low termination thresholds maximize usable battery capacity before the charger completes a cycle, enabling fuller charges for small cells.
Programmable via I2C: The bq25120 provides an I2C programming interface to configure key parameters, including charger voltage, charge current, termination thresholds, input current limit, load-switch control, flexible timers, and reset options.
Expandable power architecture: The bq25120 can be combined with other devices for additional outputs. The ultra-low-Iq buck converter TPS62743 can provide extra buck outputs. Boost converters such as the TPS61046 (12 V boost) and TPS61240 (5 V boost for sensors or small displays) can be used for display or sensor integration.