The BQ24100RHLR is a single-cell Li-Ion/Polymer charger from the bqSWITCHER™ family, rated for a 2A max charge current and a 16V supply ceiling. That 2A limit is the practical charging speed for a single 18650 or pouch cell in a handheld or portable device — enough to charge a 2000 mAh cell in about an hour without pushing the thermal budget of the 20-VFQFN exposed-pad package.
Charge current set by external resistor — no I2C needed
The charge current is constant and programmable via an external resistor. That means you set the rate with a single passive component, not a serial bus — useful for designs where the charger runs autonomously from the system MCU. The programmable features also include a timer, which acts as a safety timeout if the battery never reaches the 4.2V full-charge voltage.