USB linear charger for single-cell Li-Ion/Polymer packs
The Texas Instruments BQ24027DRCT is a linear charger IC from the bqTINY™-II series, designed to charge single-cell (1-cell) Lithium Ion or Lithium Polymer battery packs from a USB power source. It delivers a programmable constant charge current up to 500 mA maximum, with a fixed battery regulation voltage of 4.2 V. The IC integrates fault protection for over-temperature conditions and offers programmable charge current and charge-timer features.
Charge current and timer programming — setting the charge profile
The charge current is constant and programmable via an external resistor, with a maximum of 500 mA. The safety timer is also programmable, allowing the designer to set a maximum charge duration that matches the battery capacity and C-rate. These two programmable features — current and timer — are the main configuration knobs for the charge profile; no I²C or SMBus interface is used. For a typical 500 mAh to 2000 mAh single-cell Li-Ion pack, the 500 mA ceiling means a charge current of 0.25C to 1C, which is within the standard charge-rate window for most consumer cells. The timer should be set to accommodate the full CC-CV cycle; a common starting point is 3 to 6 hours depending on the cell's charge acceptance at the C-rate.
Package and thermal management — 10-VSON with exposed pad
The BQ24027DRCT is supplied in a 10-pin VFDFN with an exposed pad (3 mm × 3 mm VSON package). Surface-mount assembly per standard MSL ratings applies; the package is RoHS-compliant and shipped in Tape & Reel (TR) format.
Lifecycle status — obsolete, sourced via independent distribution
The BQ24027DRCT is listed as obsolete by the manufacturer.