Description:

The BQ2404x series devices are highly integrated Li-Ion and Li-Polymer linear charger devices targeted at space-constrained portable applications. The devices operate from a USB port or AC adapter. The high input voltage range and input overvoltage protection support low-cost, unregulated adapters. The BQ2404x devices have a single power output for charging the battery. The system load can be placed in parallel with the battery if the average system load does not allow the battery to fully charge within the 10-hour safety timer period. Battery charging occurs through the following three phases: preconditioning, constant current, and constant voltage. During all charging phases, an internal control loop monitors the IC junction temperature and reduces the charge current if the internal temperature threshold is exceeded. The charger power stage and charge current sense functions are fully integrated. The charger offers high-accuracy current and voltage regulation loops, charge status display, and charge termination. The precharge current and termination current thresholds are programmed with external resistors on the BQ24040 and BQ24045. The fast-charge current value is also programmable with an external resistor.

Features：

• Charging

– 1% charge voltage accuracy

– 10% charge current accuracy

– Pin-selectable USB 100mA and 500mA maximum input current limit

– Programmable termination and precharge thresholds – BQ24040 and BQ24045

– BQ24045 supports high-voltage (4.35V) battery chemistry

• Protection

– 30V input rating; 6.6V or 7.1V input overvoltage protection

– Input voltage dynamic power management

– 125°C thermal regulation; 150°C thermal shutdown protection

– OUT short-circuit protection and ISET short detection

– JEITA-compliant operation via battery NTC

– 1/2 fast-charge current in cold, 4.06V in hot – BQ24040 and BQ24045

– Fixed 10-hour safety timer – BQ24040 and BQ24045

• System

– Automatic termination and timer disable mode (TTDM) for missing battery packs with thermistor – BQ24040 and BQ24045

– Status indication

– Charging and complete

– Available in a small 2mm × 2mm DFN-10 package

– Integrated automatic start-up for production line testing – BQ24041

• Functional Safety (BQ24040)

– Documentation available for functional safety system design

• Safety-related certifications:

– IEC 62368-1 CB certified (BQ24040, BQ24045)

Applications:

• TWS earbuds and headsets

• Smartwatches and wristbands

• Wireless speakers

• Mobile POS

• Portable medical devices