The BQ25121AYFPT is a highly integratedbattery charge management IC that integrates the most common functions for wearable devices: Linearcharger, regulated output, load switch, manual reset with timer, and battery voltage monitor. Theintegrated buck converter is a high efficiency, low IQ switcher usingDCS-Control that extends light load efficiencydown to 10-μA load currents. The low quiescent current during operation and shutdown enablesmaximum battery life. The device supports charge currents from 5 mA to 300 mA. The input currentlimit, 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. A simple voltage basedmonitor provides battery level information to the host in 2% increments from 60% to 100% of theprogrammed V(BATREG).
Feature
- Increases System Operation Time Between Charges
- Configurable 300-mA Buck Regulator
(2.5-V Default)
- 700 nA (typical) Iq with Buck Converter Enabled (No Load)
- Configurable Load Switch or 100mA LDO Output (Load Switch 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
- Watchdog Timer Disabled
- 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 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
