Single-cell Li-Ion charger, 1.5 A ceiling, 16 V input
The Texas Instruments BQ24070RHLRG4 is a linear Li-Ion/Polymer charger for single-cell packs (4.2 V termination). It delivers a programmable constant-current charge up to 1.5 A from an input supply as high as 16 V — useful when the rail is an unregulated 12 V brick or a 5 V USB port that needs headroom for the linear pass element. The charger integrates over-temperature, reverse-current, and short-circuit protection, so the BOM can skip a separate supervisory IC for fault detection.
1.5 A max charge current — what it buys you
At 1.5 A, a typical 2000 mAh single-cell Li-Ion pack charges in about 80 minutes from the constant-current phase alone, before the constant-voltage taper. That current is programmable via an external resistor; the timer fault-protection feature (programmable via the TIMER pin) prevents indefinite charging if the termination current is never reached.
Thermal and package reality
The 20-VFQFN with exposed pad (3.5x4.5 mm) is the thermal bottleneck. A linear charger dissipates (Vin - Vbat) × Icharge as heat. At 1.5 A from a 5 V input into a 3.7 V cell, that is nearly 2 W — the PCB copper area under the pad must be sized to keep the junction below 125°C.