TI BQ24075TRGTR

The BQ2407xT series of devices are integrated lithium-ion linear chargers and system power path management devices, suitable for space-constrained portable applications. These devices are powered by a USB port or an AC adapter, support a charging current of up to 1.5A, and also feature input overvoltage protection, thus supporting unregulated adapters within the input voltage range. The USB input current limit accuracy and startup sequence of the BQ2407xT enable this device to comply with the USB-IF inrush current specification. Additionally, input dynamic power management (VIN-DPM) can prevent the charger from damaging a misconfigured USB power supply.

The BQ2407xT has a dynamic power path management (DPPM) function, which can charge the battery independently while powering the system. When the system output drops below the DPPM threshold due to the input current limit, the DPPM circuit will reduce the charging current; therefore, the charging current can be monitored at any time while powering the system load. This feature reduces the number of charge-discharge cycles on the battery, enables normal charging termination, and allows the system to operate when powered by a defective or incomplete battery pack.

Moreover, this series of chargers can provide a regulated system input, enabling the system to turn on instantly after connecting to the power supply even when the battery is fully discharged. This power path management architecture also allows compensating for the system current demand when the adapter cannot supply the peak system current, thus enabling the use of a smaller adapter.

Battery charging occurs in the following three stages: regulation, constant current, and constant voltage. During all charging stages, an internal control loop monitors the IC junction temperature and reduces the charging current if the internal temperature threshold is exceeded. The charger power stage and charging current sensing function are fully integrated.

This charger features high-precision current and voltage regulation loops, charging status indication, and charging termination functions. The input current limit and charging current can be programmed using external resistors.

• Fully compliant with USB charger standards
• Selectable maximum input current: 100mA and 500mA
• 100mA maximum current limit ensures USB-IF compliant charging
• Input-based dynamic power management (VIN-DPM) for protection against inadequate USB power sources
• 28V input rating with overvoltage protection
• Integrated dynamic power path management (DPPM) for simultaneous independent system power supply and battery charging
• System output tracks battery voltage (BQ24072T)
• Supports up to 1.5A charge current via current monitor output (ISET)
• Programmable input current limit up to 1.5A for wall adapters
• Battery disconnect via SYSOFF input
• Reverse current, short circuit, and thermal protection
• Voltage-based NTC thermistor flexible input
• Proprietary startup sequence to limit inrush current
• Status indication for charging/charge complete and power good
• Small 3mm×3mm 16-lead VQFN package

• Smartphones
• PDAs
• MP3 players
• Low-power handheld devices