Charger IC for two-series Li-ion packs — 1.2 A ceiling
The BQ24004PWPRG4 from Texas Instruments is a linear Li-ion charger IC designed specifically for two-series cells, delivering a constant charge current up to 1.2 A to a battery pack at 8.4 V.
Programmable current and timer — no I²C needed
Charge current and safety timer are set with external resistors, so the BOM stays simple and the firmware overhead is zero. The constant-current profile suits Li-ion chemistry; over-temperature protection shuts down the pass element if the die exceeds the safe limit.
Package and thermal: 20-HTSSOP with exposed pad
The 20-PowerTSSOP (4.40 mm width) includes a thermal pad on the underside. The datasheet's recommended PCB footprint ties the pad to the ground plane — without that thermal via array, the 1.2 A charge current will push the die temperature past the 70°C ambient rating in still air.