The BQ24650 device is a highly integrated switch-mode battery charge controller. It
provides input voltage regulation, which reduces charge current when input voltage falls below a
programmed level. When the input is powered by a solar panel, the input regulation loop lowers the
charge current so that the solar panel can provide maximum power output.
The BQ24650 offers a constant-frequency synchronous PWM controller with high accuracy
current and voltage regulation, charge preconditioning, charge termination, and charge status
The BQ24650 charges the battery in three phases: pre-conditioning, constant current, and
constant voltage. Charge is terminated when the current reaches 1/10 of the fast charge rate. The
pre-charge timer is fixed at 30 minutes. The BQ24650 automatically restarts the charge cycle if the
battery voltage falls below an internal threshold and enters a low quiescent current sleep mode
when the input voltage falls below the battery voltage.
The BQ24650 supports a battery from 2.1 V to 26 V with VFB set to a 2.1-V feedback
reference. The charge current is programmed by selecting an appropriate sense resistor. The BQ24650
is available in a 16 -pin, 3.5 mm × 3.5 mm2 thin QFN package.