The bq25122 is a highly integrated battery charge management IC that integrates the mostcommon functions for wearable devices: Linear charger, regulated output, load switch, manual resetwith timer, and battery voltage monitor. The integrated buck converter is a high efficiency, lowIQ switcher using DCS control that extends light load efficiency down to10-μA load currents. The low quiescent current during operation and shutdown enables maximumbattery life. The device supports charge currents from 5 mA to 300 mA. The input current limit,charge current, buck converter output voltage, LDO output voltage, and other parameters areprogrammable through the I2C interface.
The battery is charged using a standard Li-Ion charge profile with three phases:precharge, constant current and constant voltage. A voltage-based JEITA compatible battery packthermistor monitoring input (TS) is included that monitors battery temperature and automaticallychanges charge parameters to prevent the battery from charging outside of its safe temperaturerange. The charger is optimized for 5-V USB input, with 20-V tolerance to withstand linetransients. The buck converter is run from the input or battery. When in battery only mode, thedevice can run from a battery up to 4.65 V.
A configurable load switch allows system optimization by disconnecting infrequently useddevices. The manual reset with timer allows multiple different configuration options for wake arereset optimization.
Feature
- Increases System Operation Time Between Charges
- Configurable 300-mA Buck Regulator
(1.2-V Default)
- 700 nA (typical) Iq with Buck Converter Enabled (No Load)
- Configurable Load Switch or 100mA LDO Output (Load Switch enabled by default)
- Up to 300-mA Charge Current for Fast Charging
- 0.5% Accurate Battery Voltage Regulation (Configurable from 3.6 V to 4.65 V in 10-mV Steps)
- Configurable Termination Current Down to
500 μA
- Simple Voltage Based Battery Monitor
- Configurable 300-mA Buck Regulator
- Highly Integrated Solution with Small Footprint
- 2.5 mm x 2.5 mm WCSP Package and 6 External Components for Minimal Solution
- Push-Button Wake-Up and Reset with Adjustable Timers
- Power Path Management for Powering the System and Charging the Battery
- Power Path Management enables < 50 nA 150 nA Ship Mode Battery Quiescent Current for Longest Shelf Life
- Battery Charger Operates from 3.4 V – 5.5 VIN (5.5-V OVP / 20-V Tolerant)
- Dedicated Pins for Input Current Limit, Charge Current, Termination Current, and Status Output
- I2C Communication Control
- Charge Voltage and Current
- Termination Threshold
- Input Current Limit
- VINDPM Threshold
- Timer Options
- Load Switch Control
- Controls for Interrupts for Faults and Status
- System Output Voltage Adjustment
- LDO Output Voltage Adjustment
