2-cell Li-Ion/Polymer charge controller in 8-TSSOP
The Texas Instruments BQ2057WTSTR is a constant-current programmable charger IC designed for 2-cell Lithium Ion or Lithium Polymer battery packs, with a target pack voltage of 8.4V. It handles the charge termination and safety timing for portable equipment where the battery stack is two series cells.
Programmable charge current and supply range
Charge current is set by an external resistor — the IC itself is a linear controller, so the power dissipation depends on the input-to-pack voltage differential and the programmed current. Maximum supply input is 15V, which gives headroom for common 12V or 9V wall adapters.