1A single-cell Li-ion charger with USB input and on-die protection
The Texas Instruments BQ24092DGQR is a linear charger IC for single-cell Lithium Ion or Lithium Polymer battery packs. It accepts power from a USB port and delivers a programmable constant charge current up to 1 A, with a regulated float voltage of 4.2 V. On-chip fault protection covers over-voltage, over-temperature, and short-circuit conditions — no external supervisor is required for the basic safety envelope.
Charge current and thermal budget
The 1 A maximum charge current is set via an external resistor — the constant-current loop is programmable, so the BOM engineer tailors the charge rate to the cell capacity. For a 500 mAh cell, a 0.5 C rate (500 mA) keeps the die temperature rise manageable in a sealed enclosure.
Protection set and supply range
The protection block monitors the input for over-voltage, the die for over-temperature, and the output for short-circuit — all three trip thresholds are fixed on-chip. The maximum supply voltage is 6.45 V, which covers a standard 5 V USB bus with margin for cable droop and hot-plug transients. No external OVP FET is needed for the USB input.
Package and footprint notes
The BQ24092DGQR is offered in a 10-PowerTFSOP / 10-MSOP package with a body width of 0.118 inches (3.00 mm). The PCB layout must include a thermal land and via array under the pad; the recommended footprint is in the TI datasheet.
Sourcing and lifecycle posture
No official second-source or cross-reference is listed in the TI documentation, so dual-sourcing depends on a functionally equivalent part from another vendor.