Single-cell Li-Ion linear charger with 500 mA ceiling
The Texas Instruments BQ24200DGN is a linear charger IC designed for single-cell Lithium-Ion and Lithium-Polymer battery packs, delivering a constant charging current up to 500 mA with a regulated battery voltage of 4.2 V. It integrates over-temperature and short-circuit fault protection, reducing the external component count for space-constrained portable designs.
500 mA charge current — thermal and layout implications
At 500 mA, the linear regulator dissipates power as (VIN - VBAT) × ICHG. With a typical 5 V input and 4.2 V battery, the drop is 0.8 V × 0.5 A = 0.4 W. The programmable current and timer features let the firmware tailor the charge profile without external resistors.
