BQ24020

The bqTINY-II series are highly-integrated, flexible Li-Ion linear charge and system power management devices for space-limited charger applications. In a single monolithic device, the bqTINY-II offers integrated USB-port and ac-adapter supply management with autonomous power-source selection, power-FET and current-sensor interfaces, high-accuracy current and voltage regulation, charge status, and charge termination.

The bqTINY-II automatically selects the USB-port or the ac-adapter as the power source for the system. In the USB configuration, the host can select from two preset charge rates of 100 mA or 500 mA. In the ac-adapter configuration, an external resistor sets the system or charge current.

The bqTINY-II charges the battery in three phases: conditioning, constant current, and constant voltage. Charge is terminated based on minimum current. An internal charge timer provides a backup safety for charge termination. The bqTINY-II automatically restarts the charge if the battery voltage falls below an internal threshold. The bqTINY-II automatically enters sleep mode when both supplies are removed.

Different versions of the bqTINY-II offer many additional features. These include a temperature-sensor input for detecting hot or cold battery packs, a power-good output (PG) indicating the presence of input power, a TTL-level charge-enable input (CE) used to disable or enable the charge process, and a TTL-level timer and taper-detect enable input (TTE) used to disable or enable the fast-charge timer and charge termination.