4A programmable charger for 1-3 cell Li-ion packs
The Texas Instruments BQ24171RGYR is a constant-current, constant-voltage Li-Ion/Polymer charger IC that handles 1 to 3 series cells with a programmable charge current up to 4A. The 17V maximum input voltage lets it work off 5V USB, 12V automotive, or unregulated wall adapters without a pre-regulator — a practical fit for portable instruments, power tools, and medical equipment that share a common charger platform.
The 4A maximum charge current is programmable, so you can set the rate to match the cell capacity and thermal budget of your enclosure — a 2 Ah pack can charge at 0.5C (1A) or 2C (4A) depending on the cell datasheet limits and your cooling. The 1-3 cell support covers single-cell handhelds, two-cell power-tool packs, and three-cell medical or industrial battery stacks, all with the same IC and a resistor change. On-chip fault protection for over-current, over-temperature, and over-voltage reduces external monitoring circuitry and simplifies the safety review for battery-powered products that need UL or IEC 62368 compliance.